managed by ut-battelle for the department of energy cern 4 th tlep mini-workshop 2013 longitudinal...
DESCRIPTION
3Managed by UT-Battelle for the Department of Energy Presentation_name Longitudinal beam-beam kick history 1) In 60 beam-beam colliders saw first beam-beam effects; 2) The origin was thought to be the transverse effects; 3) Then longitudinal modulation of the transverse kick was thought to be most important; 4) Derbenev, Skrinsky (around 1970) started to think if energy change is possible in beam-beam collisions; 5) 1972 – they publish the first paper on longitudinal beam-beam effects; 6) The effect was small for the first collider and then long forgotten; 7) The effect was recalled in 80s in Novosibirsk when high-luminosity colliders were considered; 8) My recollection – approximately the same time Koji Hirata (KEK) started the same development; 9) I was asked to advance the topic and get general formulas for the kick not only on axis (as in Derbenev, Skrinsky) – 1991 paper; 10) Below I follow its derivation of the kick extending calculations to flat beams;TRANSCRIPT
Managed by UT-Battellefor the Department of Energy
CERN 4th TLEP Mini-Workshop 2013
Longitudinal Beam-Beam
Effects at TLEP (Novosibirsk Phi factory experience
recollection)
Resistive wall instabilities (VLHC experience -gtTLEP
LHeC)
V Danilov
SNS AP group
2 Managed by UT-Battellefor the Department of Energy Presentation_name
Talk outline
History of the finding Underling physics Basic formulas big picture estimations for
LEP3 and TLEP Transverse resistive wall instabilities a) Closed Orbit Instability b) TMCI c) Other effects
3 Managed by UT-Battellefor the Department of Energy Presentation_name
Longitudinal beam-beam kick history1) In 60 beam-beam colliders saw first beam-beam effects
2) The origin was thought to be the transverse effects
3) Then longitudinal modulation of the transverse kick was thought to be most important
4) Derbenev Skrinsky (around 1970) started to think if energy change is possible inbeam-beam collisions5) 1972 ndash they publish the first paper on longitudinal beam-beam effects6) The effect was small for the first collider and then long forgotten7) The effect was recalled in 80s in Novosibirsk when high-luminosity colliders were considered8) My recollection ndash approximately the same time Koji Hirata (KEK) started the same development9) I was asked to advance the topic and get general formulas for the kick not onlyon axis (as in Derbenev Skrinsky) ndash 1991 paper10) Below I follow its derivation of the kick extending calculations to flat beams
4 Managed by UT-Battellefor the Department of Energy Presentation_name
Simplified physics
e-
e+
IP
E
On axis
Head of bunch energy decreased ndash acts like defocusing cavity for positive momentumcompaction
e+
IP
E
e-
Trailing particle energy Increased ndash valid only forelectron-positron collisions
General case1
2
1 2
Same particlesRed-gets energyBlue-gives energy to redThe exchange happens Not at the same time
5 Managed by UT-Battellefor the Department of Energy
Basic Formulas (1)
Presentation_name
Integrate with Gaussian transverse distributions
Round beam first term agrees with Derbenev Skrinsky (1972)
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
2 Managed by UT-Battellefor the Department of Energy Presentation_name
Talk outline
History of the finding Underling physics Basic formulas big picture estimations for
LEP3 and TLEP Transverse resistive wall instabilities a) Closed Orbit Instability b) TMCI c) Other effects
3 Managed by UT-Battellefor the Department of Energy Presentation_name
Longitudinal beam-beam kick history1) In 60 beam-beam colliders saw first beam-beam effects
2) The origin was thought to be the transverse effects
3) Then longitudinal modulation of the transverse kick was thought to be most important
4) Derbenev Skrinsky (around 1970) started to think if energy change is possible inbeam-beam collisions5) 1972 ndash they publish the first paper on longitudinal beam-beam effects6) The effect was small for the first collider and then long forgotten7) The effect was recalled in 80s in Novosibirsk when high-luminosity colliders were considered8) My recollection ndash approximately the same time Koji Hirata (KEK) started the same development9) I was asked to advance the topic and get general formulas for the kick not onlyon axis (as in Derbenev Skrinsky) ndash 1991 paper10) Below I follow its derivation of the kick extending calculations to flat beams
4 Managed by UT-Battellefor the Department of Energy Presentation_name
Simplified physics
e-
e+
IP
E
On axis
Head of bunch energy decreased ndash acts like defocusing cavity for positive momentumcompaction
e+
IP
E
e-
Trailing particle energy Increased ndash valid only forelectron-positron collisions
General case1
2
1 2
Same particlesRed-gets energyBlue-gives energy to redThe exchange happens Not at the same time
5 Managed by UT-Battellefor the Department of Energy
Basic Formulas (1)
Presentation_name
Integrate with Gaussian transverse distributions
Round beam first term agrees with Derbenev Skrinsky (1972)
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
3 Managed by UT-Battellefor the Department of Energy Presentation_name
Longitudinal beam-beam kick history1) In 60 beam-beam colliders saw first beam-beam effects
2) The origin was thought to be the transverse effects
3) Then longitudinal modulation of the transverse kick was thought to be most important
4) Derbenev Skrinsky (around 1970) started to think if energy change is possible inbeam-beam collisions5) 1972 ndash they publish the first paper on longitudinal beam-beam effects6) The effect was small for the first collider and then long forgotten7) The effect was recalled in 80s in Novosibirsk when high-luminosity colliders were considered8) My recollection ndash approximately the same time Koji Hirata (KEK) started the same development9) I was asked to advance the topic and get general formulas for the kick not onlyon axis (as in Derbenev Skrinsky) ndash 1991 paper10) Below I follow its derivation of the kick extending calculations to flat beams
4 Managed by UT-Battellefor the Department of Energy Presentation_name
Simplified physics
e-
e+
IP
E
On axis
Head of bunch energy decreased ndash acts like defocusing cavity for positive momentumcompaction
e+
IP
E
e-
Trailing particle energy Increased ndash valid only forelectron-positron collisions
General case1
2
1 2
Same particlesRed-gets energyBlue-gives energy to redThe exchange happens Not at the same time
5 Managed by UT-Battellefor the Department of Energy
Basic Formulas (1)
Presentation_name
Integrate with Gaussian transverse distributions
Round beam first term agrees with Derbenev Skrinsky (1972)
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
4 Managed by UT-Battellefor the Department of Energy Presentation_name
Simplified physics
e-
e+
IP
E
On axis
Head of bunch energy decreased ndash acts like defocusing cavity for positive momentumcompaction
e+
IP
E
e-
Trailing particle energy Increased ndash valid only forelectron-positron collisions
General case1
2
1 2
Same particlesRed-gets energyBlue-gives energy to redThe exchange happens Not at the same time
5 Managed by UT-Battellefor the Department of Energy
Basic Formulas (1)
Presentation_name
Integrate with Gaussian transverse distributions
Round beam first term agrees with Derbenev Skrinsky (1972)
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
5 Managed by UT-Battellefor the Department of Energy
Basic Formulas (1)
Presentation_name
Integrate with Gaussian transverse distributions
Round beam first term agrees with Derbenev Skrinsky (1972)
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
6 Managed by UT-Battellefor the Department of Energy
Basic Formulas (2)
Presentation_name
Important for simulations - not only to account for energy changeBut to preserve symplecticity
Recent addition ndash flat beamxy
On-axis result
)(2 yyxxreE
2 xy
yyNeE
Same as round beam with reduced number of particlesRatio of sizes is an extra factor that indicates which particles contribute to the energy change
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
7 Managed by UT-Battellefor the Department of Energy
Coherent Effects
Presentation_name
Consider short bunches (length shorter or comparable to the IP beta function
k is the coefficient of voltage reduction
The threshold for unstable coherent behavior twice as lower as in Incoherent motion ndash with the particle increase wersquoll see first the coherent instability
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
8 Managed by UT-Battellefor the Department of Energy
LEP3TLEP estimations
Presentation_name
880
6101271210
320430410910 196
129
MV
U
1
6101243210
220430410910 196
129
MV
U
For LEP3
For TLEP (given by F Zimmermann)The results are about 3 orders of magnitude lessThan the gradients of the planned RF
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
9 Managed by UT-Battellefor the Department of Energy
Synchro-betatron motion with e-kickTherefore the effect for TLEP from synchrotron motion is in
modulation of betatron phase with the longitudinal position and energy but the kick has to be always included into simulation to preserve symplecticity
Very peculiar growth of particle amplitudes was found and later described in ldquoNegative momentum compaction in the longitudinal beam-beam effectsrdquo
VV Danilov EA Perevedentsev DN Shatilov (Novosibirsk IYF) HEACC 1992
ds=dE db= -ds0 (dE is the energy change due to one collision particle has large angle)
Presentation_name
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
10 Managed by UT-Battellefor the Department of Energy
Resulting Loss of Particles (D Shatilov)
Presentation_name
Novosibirsk old phi-factory project Negative momentum compaction
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
11 Managed by UT-Battellefor the Department of Energy
Resistive wall instabilities
1 Type ndash Closed Orbit Instability ndash extreme number of particles (more relevant to LHeC)
Classical TMCI (more relevant to TLEP) Very Large Hadron Collider experience ndash
resistive wall wake is dominant because of general trend of size and cost reduction (its contribution grows like inverse cube of vacuum chamber radius)
All instabilities are most important and calculated at injection energy of 10 GeV
Presentation_name
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
12 Managed by UT-Battellefor the Department of Energy
Extreme case-closed orbit instability Fields so high they distort the orbit Discovered while we worked on SNS Ring
(Danilov et al PRSTAB 2001) The threshold LHeC Nth=71013 (nu=05) Design 61013 TLEP Nth=551012 (nu=004) Design 91012
ndash the working point has to be further away from integer
Presentation_name
grb
No
bbth
2 22
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
13 Managed by UT-Battellefor the Department of Energy
TMCI ndash Transverse Mode Coupling Instability
Presentation_name
VLHC mode diagramThis instability was present in LEP at injection energy
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
14 Managed by UT-Battellefor the Department of Energy
Basic TMCI ndash 1 bunch instability Short bunch ndash resistive wall wake
contribution is large 1sqrt(length) ndash probably dominant wake
Beam Stability Issues in Very Large Hadron Collider A Burov J Marriner V Shiltsev lowast FNAL Batavia IL 60510 V Danilov ORNL Oak Ridge TN 37831 G Lambertson LBL Berkeley CA 94720 NIM 2000
b- is the vacuum chamber radius ndash critical parameter (determines cost and stability)
Presentation_name
mkm
cmb
TeVE
mN slth
250520)90
(0050310
10241 310
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
15 Managed by UT-Battellefor the Department of Energy
TLEP threshold
Nth TLEP=181010 at injection ndash 40 times below the design value
Mitigation ndash injection synchrotron tune should be increased 10 times
The length at injection has to be larger Some other possibilities
Presentation_name
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
16 Managed by UT-Battellefor the Department of Energy
Other associated transverse problems
Since Closed Orbit Instability threshold is close no doubt there are multi bunch instabilities
Requires feedback VLHC problem ndash detuning wake cause large
spread of betatron tunes It could be fatal for the beam (important for LHeC and TLEP)
Shape of the vacuum chamber determines it and its important to optimize it
Presentation_name
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
17 Managed by UT-Battellefor the Department of Energy
Vacuum chamber ndash round or elliptical
To cope TMCI ndash synchrotrone tune asymp1 Betatron tuneshift asymp1 the betatron incoherent
tune spread due to detuning wake is around 1 Integer and half-integer resonance crossing- low beam lifetime
Round VC ndash no detuning wake But bad from dispersionenergy acceptance space consideration
Maybe there exist solution with round cavity and accordingly shaped poles
Presentation_name
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-
18 Managed by UT-Battellefor the Department of Energy Presentation_name
Conclusion Low IP beta high current factories encounter new
type of effects ndash large energy change due to fields of counter beams but because of very high RF gradients the energy change effect is negligible for TLEP as compared to low energy Phi-factory
Resistive wall wake become large for short bunches ndash the TLEP thresholds at injection are low the injection should be taken care of
Closed Orbit instability threshold is close to the design number of particles -an integer resonance should be avoided
Detuning wake can cause a large spread of particlersquos tunes ndash needs to be worked on
- CERN 4th TLEP Mini-Workshop 2013
- Talk outline
- PowerPoint Presentation
- Slide 4
- Basic Formulas (1)
- Basic Formulas (2)
- Coherent Effects
- LEP3TLEP estimations
- Synchro-betatron motion with e-kick
- Resulting Loss of Particles (D Shatilov)
- Resistive wall instabilities
- Extreme case-closed orbit instability
- TMCI ndash Transverse Mode Coupling Instability
- Basic TMCI ndash 1 bunch instability
- TLEP threshold
- Other associated transverse problems
- Vacuum chamber ndash round or elliptical
- Conclusion
-