beam current measurements - cern · 2011-07-08 · beam current measurements the state of art d....
TRANSCRIPT
Beam Current MeasurementsThe State of Art
D. BelohradCERN, Geneva, Switzerland
May 18, 2011
PART I
What is the beam current/charge
What is its origin
The Intensity Measurement
3
· Movement of electrically charged particles generates a current· Beam = charged particles which move around the accelerator
I Beam intensity / Beam charge:I either an equivalent DC currentI or number of charged particles in a ’region of interest’
I Region of interest (ROI):specific time interval corresponding to a measured
structure→ next slide
I The number of charges:
NP =Q
e=
∫ROI ibeam(t)dt
e≈ I · t
e(1)
Q is a measured charge, e = 1.602× 10−19 C.
ibeam is the beam current intercepted by measurement device
Region of interest
4
Repetition rate
t [µs]
Batch length
Fine structure t [µs]
• Repetition rate = CW to seconds
• Batch length = ns to ms or CW
• Bunch spacing = ps to ms
• Bunch length σ = fs to nsσ
IDC,eq
IDC
Bunch spacing
Q =∫
ROI ib(t)dt
Bunch pattern example
Repetition rate
t [µs]
Batch length
Fine structure t [µs]
• Repetition rate = CW to seconds
• Batch length = ns to ms or CW
• Bunch spacing = ps to ms
• Bunch length σ = fs to nsσ
IDC,eq
IDC
Bunch spacing
Q =∫
ROI ib(t)dt
Bunch pattern example
I LINACs: equivalent DC current in a batch
I electron machines/fine structure: bunch charge
I circulating beam: bunch charge / DC beam current
I other, e.g. total charge over a revolution period
Additional information, e.g. amount of debunched beam
Region of interest
5
Repetition rate
t [µs]
Batch length
Fine structure t [µs]
• Repetition rate = CW to seconds
• Batch length = ns to ms or CW
• Bunch spacing = ps to ms
• Bunch length σ = fs to nsσ
IDC,eq
IDC
Bunch spacing
Q =∫
ROI ib(t)dt
Bunch pattern example
Repetition rate
t [µs]
Batch length
Fine structure t [µs]
• Repetition rate = CW to seconds
• Batch length = ns to ms or CW
• Bunch spacing = ps to ms
• Bunch length σ = fs to nsσ
IDC,eq
IDC
Bunch spacing
Q =∫
ROI ib(t)dt
Bunch pattern example
I LINACs: equivalent DC current in a batch
I electron machines/fine structure: bunch charge
I circulating beam: bunch charge / DC beam current
I other, e.g. total charge over a revolution period
Additional information, e.g. amount of debunched beam
PART II
What measurement methods are available?
What can measure the charge
7
What can give precise information about the charge?I a measurement instrument:
I provide deterministic absolute measurement valueI must be calibrated
I direct calibration - not many devices availableI indirect calibration - uses directly calibrated devices
I uncertainty of the measurement and calibration standards
I dynamic range and noise levels are of utmost importance
I Can provide: instant current, average current, bunch charge,turn charge etc.
I used for machine protection (e.g. Reeg, H. et al., EPAC2006)
Charge measurement devices
8
I non-intercepting - inductive/capacitive coupling to the beam
→ insignificant impact on the beam→ couple to EM image current ’treatment’I inductive: FBCTs, DCCTs, WCMs, striplines (EM coupling)I capacitive: BPMs, all sorts of button-style pick-upsI magnetic sensors: SQUIDs, Magneto-resistive sensors, CCCs,
nDCCT
I intercepting - direct interaction with the beam
→ absorption of significant part of the energyI Faraday cups (beam stoppers), SEM grids, screens, Ionisation
chambersI even Wire scanners can provide intensity
Charge measurement devices
9
I non-intercepting - inductive/capacitive coupling to the beam
→ insignificant impact on the beam→ couple to EM image current ’treatment’I inductive: FBCTs, DCCTs, WCMs, striplines (EM coupling)I capacitive: BPMs, all sorts of button-style pick-upsI magnetic sensors: SQUIDs, Magneto-resistive sensors, CCCs,
nDCCT
I intercepting - direct interaction with the beam
→ absorption of significant part of the energyI Faraday cups (beam stoppers), SEM grids, screens, Ionisation
chambersI even Wire scanners can provide intensity
Charge measurement devices
10
I non-intercepting - inductive/capacitive coupling to the beam
→ insignificant impact on the beam→ couple to EM image current ’treatment’I inductive: FBCTs, DCCTs, WCMs, striplines (EM coupling)I capacitive: BPMs, all sorts of button-style pick-upsI magnetic sensors: SQUIDs, Magneto-resistive sensors, CCCs,
nDCCT
I intercepting - direct interaction with the beam
→ absorption of significant part of the energyI Faraday cups (beam stoppers), SEM grids, screens, Ionisation
chambersI even Wire scanners can provide intensity
PART II
What measurement methods are available?
A) Non-DC beam current measurementsWhat is needed to get the beam signal?
How to process the beam signal?Calibration?
B) DC beam current measurementsDCCT and its calibration
MR sensors
PART II
What measurement methods are available?A) Non-DC beam current measurements
What is needed to get the beam signal?How to process the beam signal?
Calibration?
B) DC beam current measurementsDCCT and its calibration
MR sensors
PART II
What measurement methods are available?A) Non-DC beam current measurements
What is needed to get the beam signal?How to process the beam signal?
Calibration?
B) DC beam current measurementsDCCT and its calibration
MR sensors
Non-DC: What is needed to get the beam signal
14
A) Non-DC beam current measurements
We might use these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
Note:Faraday cups measure down to DC as well, but ...
Non-DC: What is needed to get the beam signal
15
A) Non-DC beam current measurements
We might use these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
Note:Faraday cups measure down to DC as well, but ...
Faraday cups
16
Measurement of low to mA currents
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
Faraday cup
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
Faraday cup
Provides pA resolution with excellent absolute accuracy
Faraday cups
17
Generated secondary particles can escape the cup
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
Faraday cup
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
Faraday cup
Install longer cup, or ...
Faraday cups
18
Generated secondary particles can escape the cup
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
HV
Electrostatic deflector
Ibeam
Rl Vout ≈ Rl · Ibeam
Long transmission line
I → U
HV
Electrostatic deflector
deflect them back using HV higher than mean SE energy
Implementations
19
SE deflection using electrostatic shieldingSE deflection using electrostatic shielding
SE deflection using electrostatic shieldingSE deflection using electrostatic shielding
I USR/FLAIR anti-protonstorage
I mainly for proton beams
I p− measurements limited dueto 100 MeV+ p-p−
annihilation
I 1 µA down to fA, res. < 5 fA
Harasimowicz, J. et al., BIW2010
Properties
20
Extremely accurate measurements down to pA levels, used asabsolute calibration standard
I cup heat-load with intense beams require active cooling
I emission of secondary particles
I may have problems with attraction of particles flying around(e.g. electron showers)
Signal transmission bandwidth in hundreds of MHz. For electronmachines/fine beam structures appropriate HIBW connection tothe current meter must be provided to tens of GHz
→ Fast Faraday Cups (FFC), e.g. ELETTRA
FFC principle of operation
21
2.4mm Vacuum Feedthrough
Beam attenuators
Bellows for Fine Tuning
Faraday Cup
Stripline Circuit
C. Deibele, Fast Faraday Cup, SNS
2.4mm Vacuum Feedthrough
Beam attenuators
Bellows for Fine Tuning
Faraday Cup
Stripline Circuit
C. Deibele, Fast Faraday Cup, SNS
Ferianis., M. et al. DIPAC 2003Up to 40 GHz transmission bandwidth
Implementations
22
C. Deibele, Fast Faraday Cup, SNSC. Deibele, Fast Faraday Cup, SNS
Non-DC: What is needed to get the beam signal
23
We might use these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
Wall image current
24
Any moving charged particle is accompanied with EM field:
FWHM ≈ 1.4a
γ
l [m]
λb[C
m−1]
2av
r [mm]
B[T]
Skin depth dependent
Distribution of the mirror charge and flux lines
FWHM ≈ 1.4a
γ
l [m]
λb[C
m−1]
2av
r [mm]
B[T]
Skin depth dependent
Distribution of the mirror charge and flux lines
E field looks as a pillbox for relativistic speeds and causes a chargedeposit on the inner wall of the vacuum chamber. Depositedcharge moves with particle and generates current = Wall ImageCurrent (WIC). B field gets attenuated
Non-intercepting & Wall image current
25
As beam signal is “the source” of the information about the beamcharge, we need to intercept it
I couple to EM field produced by the beam currentI diverge the wall image currentI install the detector in the vacuum chamber
I Why?I Electric field: cancelledI Magnetic field: Attenuation by ≈ 8.7 dB by one skin-depth
length: non-magnetic conductor→ δ =√10·1032π
√ρf :
1 kHz 10 kHz 100 kHz 1 MHz 10 MHz
Copper [mm] 2.1 0.66 0.21 0.066 0.021
I 3mm copper tube: A≈50 dB @ 10MHzI radio with ≈30dB dynamic range to intercept weakest beam
signal attenuated by 50 dB?
Non-intercepting & Wall image current
26
As beam signal is “the source” of the information about the beamcharge, we need to intercept it
I couple to EM field produced by the beam currentI diverge the wall image currentI install the detector in the vacuum chamber
I Why?
I Electric field: cancelledI Magnetic field: Attenuation by ≈ 8.7 dB by one skin-depth
length: non-magnetic conductor→ δ =√10·1032π
√ρf :
1 kHz 10 kHz 100 kHz 1 MHz 10 MHz
Copper [mm] 2.1 0.66 0.21 0.066 0.021
I 3mm copper tube: A≈50 dB @ 10MHzI radio with ≈30dB dynamic range to intercept weakest beam
signal attenuated by 50 dB?
Non-intercepting & Wall image current
27
As beam signal is “the source” of the information about the beamcharge, we need to intercept it
I couple to EM field produced by the beam currentI diverge the wall image currentI install the detector in the vacuum chamber
I Why?I Electric field: cancelledI Magnetic field: Attenuation by ≈ 8.7 dB by one skin-depth
length: non-magnetic conductor→ δ =√10·1032π
√ρf :
1 kHz 10 kHz 100 kHz 1 MHz 10 MHz
Copper [mm] 2.1 0.66 0.21 0.066 0.021
I 3mm copper tube: A≈50 dB @ 10MHzI radio with ≈30dB dynamic range to intercept weakest beam
signal attenuated by 50 dB?
Capacitive pick-up
28
is(t)
Vo(t) R
ba
C
h
ib(t)
+++++--------
+++++--------
Principle of capacitive pick-up
is(t)
Vo(t) R
ba
C
h
ib(t)
+++++--------
+++++--------
Principle of capacitive pick-up
I conductive electrode subjected to charge deposit → chargeflows through R
I RC filter limits the BW (C includes cables if electrodeimpedance not matched!)
I split the electrodes and you get capacitive BPM
Capacitive pick-up
29
I sensitivity ≈ 10 nV/nA, resolution down to 20 pA/e
I Intensity measurement using sum signal:∫v(t)dt = Q · Z2 · Φ
2πI sum suppresses first order position dependenceI using math third and fifth order can be eliminated as well, but:
Pick-up electrode size mattersPick-up electrode size matters
I Pickups/BPMs are many. Averaging over a ring increasesresolution (e.g. ESFR storage ring 224 BPMs factor of 15,Scheidt, MOPD64)
Button pick-up
30
Possible realisationsPossible realisations
Non-DC: What is needed to get the beam signal
31
We might use these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
To measure intensity using WCMs
32
is(t) R
ib(t)
Ceramics insertion
vs(t)
2a
FWHM ≈ 1.4a
γ
LHF
LLF
Cgap
Wall Current Monitor
is(t) R
ib(t)
Ceramics insertion
vs(t)
2a
FWHM ≈ 1.4a
γ
LHF
LLF
Cgap
Wall Current Monitor
I Direct measurement of a wall current
I Bandwidth from few kHz to tens GHz range (e.g. RHIC 3 kHzto 6 GHz, Cameron, PAC99)
Practical implementation ...
33
WCM for CERN CTF3, Odier, P. DIPAC2003, D’Elia, EPAC08WCM for CERN CTF3, Odier, P. DIPAC2003, D’Elia, EPAC08
I BW≈100kHz-20GHzI Ferrite to diverge LF via external bypassI signal from 8 feedthroughs combined using resistive combiners
Practical implementation ...
34
Suwada, T., KEKSuwada, T., KEK
I 2.5Ω ceramics resistance (Alumina+carbon powder)I 4 pick-up electrodes + combinerI up to 2.5GHz BW
Non-DC: What is needed to get the beam signal
35
We might use these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
To measure intensity using FBCTs
36
R0
Ns
RF connection
Measurement output
ib(t)
Ceramic gapNp
50ΩCalibration input
Fast Beam Current Transformer
R0
Ns
RF connection
Measurement output
ib(t)
Ceramic gapNp
50ΩCalibration input
Fast Beam Current Transformer
I Bandwidth from few Hz to GHz rangeI typ. resolution 2-5 pC, but sub pC optimisations ongoing
(< 1 pC see Werner, MOPD65)I measurement winding optimised to match cable on HFI Not always High-µ material (ex. Reeg, H., GSI, FCT using
Ferroxcube 3E25, τ ≈ 1 µs)
To measure intensity using FBCTs
37
ib(t)
Ls = L0 · n2
R
CVc
I(t) = c1e−λ1t + c2e
−λ2t, λ1,2 =R
2Ls±
√√√√√√√R2
4L2s
− 1
LsC
is(t)
1 : n
FBCT equivalent lumped circuit
ib(t)
Ls = L0 · n2
R
CVc
I(t) = c1e−λ1t + c2e
−λ2t, λ1,2 =R
2Ls±
√√√√√√√R2
4L2s
− 1
LsC
is(t)
1 : n
FBCT equivalent lumped circuit
Works as RLC circuit, can be used in two measurement modes:
I R2
4L2s− 1
LsC> 0: time constant τ = Ls/R,
Is = Ib/n→integrated signal related to charge
I R2
4L2s− 1
LsC< 0: C charged during pulse, then resonant
discharge→ discharge amplitude proportional to # of charges(e.g. Clarke-Gayther, EPAC96)
Practical implementation ...
38
Resonant-mode FBCT:
Reeg, H., Resonant mode BCT for GSI HEBT linesReeg, H., Resonant mode BCT for GSI HEBT lines
I peak detector to detect the voltage over capacitorI 4 dynamic ranges down to 10 pC resolution
I offset/zero value fluctuations due to noise rectification of thepeak detector circuit
I precision of calibration due to uncertain coupling efficiency ofsingle turn cal. winding
Non-DC: What is needed to get the beam signal
39
We have used one of these to get the beam signal:
Faraday cupsBPMs and capacitive pick-ups
WCMsFBCTs
and we get this ...
Missing DC component must be compensated
t [ns/µs]
I b[A]
Beam signal provided by above devices, τ short wrt beam repetition
Missing DC component must be compensated
t [ns/µs]
I b[A]
Beam signal provided by above devices, τ short wrt beam repetition
and then we have to process it by the electronics ...
Non-DC: processing electronics
40
like this ... (electronics guy prefers FPGA over Matlab)
Numericprocessing
BLRADC ApplicationFPGA
Memory
VME64xcontroller
Signal processing
Numericprocessing
BLRADC ApplicationFPGA
Memory
VME64xcontroller
Signal processing
Note: BLR = Base Line RestorerThis method work only if sampling rate is appropriate.
Non-DC: processing electronics
41
ADC BLR
Dynamic rangenon-linearity
residual offsetslew-rate and BW
Dynamic rangeINL & DNL
sampling rateresolution
Based on beamtemporalproperties
(e.g. bunch pattern)
NOISESystematic
ApplicationFPGA
Memory
VME64xcontroller
Signal processing
ADC BLR
Dynamic rangenon-linearity
residual offsetslew-rate and BW
Dynamic rangeINL & DNL
sampling rateresolution
Based on beamtemporalproperties
(e.g. bunch pattern)
NOISESystematic
ApplicationFPGA
Memory
VME64xcontroller
Signal processing
Base line restorer must be based on temporal properties of thebeam: one must know, where the beam cannot be. However,working with integrated value makes restoration more difficult →maybe doing that before integration is a good idea ...
BTW: this is the LHC FBCT system
Non-DC: processing electronics
42
ADCBLR
Dynamic rangenon-linearity
residual offsetslew-rate and BW
Dynamic rangeINL & DNL
sampling rateresolution
NOISESystematic
ApplicationFPGA
Memory
VME64xcontroller
Signal processing
ADCBLR
Dynamic rangenon-linearity
residual offsetslew-rate and BW
Dynamic rangeINL & DNL
sampling rateresolution
NOISESystematic
ApplicationFPGA
Memory
VME64xcontroller
Signal processing
BLR & integrator are analogue processing blocks, difficult to tune...
Non-DC: analogue BLR example
43
Schottky diode based analogue BLRSchottky diode based analogue BLR
t[ns]
t[ns]
t[ns]
Vc(t)
Von(t)
Vt(t)
Sampling points
BLR signals
t[ns]
t[ns]
t[ns]
Vc(t)
Von(t)
Vt(t)
Sampling points
BLR signals
Non-DC: analogue integrator example
44
Clockand
synchronisation
Beam synchronous timing
CfRg
−
+
Vout = −∫ t0
Vin
RgCf± VIQ1 ∓ VIQ2
Vin ADCIib & Vio
compensation
MOSFETdriver
VIQ2
Ccomp
MOSFET driver
VIQ1
CfRg
−
+
Vout = −∫ t0
Vin
RgCf± VIQ1 ∓ VIQ2
Iib & Vio
compensation
MOSFETdriver
VIQ2
Ccomp
MOSFET driver
VIQ1
ADC
FPGAprocessingof
twoparalleldatastream
s
Streaming data integration
Clockand
synchronisation
Beam synchronous timing
CfRg
−
+
Vout = −∫ t0
Vin
RgCf± VIQ1 ∓ VIQ2
Vin ADCIib & Vio
compensation
MOSFETdriver
VIQ2
Ccomp
MOSFET driver
VIQ1
CfRg
−
+
Vout = −∫ t0
Vin
RgCf± VIQ1 ∓ VIQ2
Iib & Vio
compensation
MOSFETdriver
VIQ2
Ccomp
MOSFET driver
VIQ1
ADC
FPGAprocessingof
twoparalleldatastream
s
Streaming data integration
Well, very complex for such small thing as integrator
Devices calibration
45
Faraday cups electronics chain calibration by DC currentPickups compared to DCCTs or FBCTs, or to Faraday cupWCMs compared to DCCTs or FBCTs, or to Faraday cupFBCTs absolute calibration using current or charge source
Matching the measurement result with known current/chargepermits to calculate gain.DC current sources of no-use for FBCTs → require pulsed source,calibration signal discharged into calibration turn.
t [µs]
V [V ]
∆t
NP =∫∆t0 i(t)dt
e = C·Vce = k · 〈acquired value〉
Charge mode calibration
Vc
t [µs]
I [mA]
∆t
Ic
NP = Ic·∆te = k · 〈acquired value〉
Current mode calibration
Two pulse-mode calibration methods
t [µs]
V [V ]
∆t
NP =∫∆t0 i(t)dt
e = C·Vce = k · 〈acquired value〉
Charge mode calibration
Vc
t [µs]
I [mA]
∆t
Ic
NP = Ic·∆te = k · 〈acquired value〉
Current mode calibration
Two pulse-mode calibration methods
Absolute accuracy of 1 to 5 % of the measurement full scale.
Pulsed current source
46
for those interested, e.g.:
VHV
HV off
ADC
HV
Lx
RlRel
Rc
Cc
Rd
Q2Q1
ADC
Ic
Rm
IcalibVcalib
LoadInPrecharge
Rc
Cc
t[ns]
ILx[A]
Pulsed current sink
VHV
HV off
ADC
HV
Lx
RlRel
Rc
Cc
Rd
Q2Q1
ADC
Ic
Rm
IcalibVcalib
LoadInPrecharge
Rc
Cc
t[ns]
ILx[A]
Pulsed current sink
Calibration by charge
47
for those interested:
t[ns]
iLx[A]
Q = Cc ·HV
VHV
HV off
ADC
HV
Q2
LoadIn
Rc
Cc
Lx
RlRel
Charge-type calibrator
t[ns]
iLx[A]
Q = Cc ·HV
VHV
HV off
ADC
HV
Q2
LoadIn
Rc
Cc
Lx
RlRel
Charge-type calibrator
Concluding Non-DC electronics components
48
There are of course other methods how to obtain the chargeinformation from the beam signal acquired by discussed devices,e.g.:
I observation of initial amplitude of resonant-mode transformer
I observation of specific harmonic frequency of the beam
I integrating current transformer (e.g. Vos., SL/94-18, CERN)
I dark current monitor (see today’s talk of D. Lipka, WEOC03)
See the references section at the end of this presentation ...
PART II
What measurement methods are available?A) Non-DC beam current measurements
What is needed to get the beam signal?How to process the beam signal?
B) DC beam current measurementsHow DCCTs and Magneto-resistance sensors work
DCCT - principle of operation
50
t
B[T ] B[T ]
H [Am−1] H [Am−1]
−Imod[A] Imod[A]
t[s]
t[s]
|A| |A|
1 3 5 7 f
fmod
f
fmod
1 3 5 72 4 6
Vmod[V ]
~
+
-
+
-
+ -
+
-
f2
Ib = q · pulse length
βc
f1
I/V generator
Vdc
Idc
Ib = 0 Ib > 0
Saturationthreshold
Harmonics production
DCCT: principle of operation
t
B[T ] B[T ]
H [Am−1] H [Am−1]
−Imod[A] Imod[A]
t[s]
t[s]
|A| |A|
1 3 5 7 f
fmod
f
fmod
1 3 5 72 4 6
Vmod[V ]
~
+
-
+
-
+ -
+
-
f2
Ib = q · pulse length
βc
f1
I/V generator
Vdc
Idc
Ib = 0 Ib > 0
Saturationthreshold
Harmonics production
DCCT: principle of operation
DCCT design issues
51
I Modulation current/voltage:I what signal: triangular, sine, squareI high voltage/current amplitude to drive cores into saturationI generator signal purity (minimise even components of fmod)
when non-linear loadI Choice of modulation frequency limits the modulator BW:
I crystalline material (NiFe): few hundreds HzI amorphous/nanocrystalline material (Fe, Co-based): few kHz
I Magnetic material used:I µr ≥ 50000
I low BH curve area
I low coercive fieldHc ≈ 1 A/m
I wound using combinationof mg. material + Mylar(typ. 20/5 µ ratio) tominimise eddy currentlosses
I low magnetostriction
I small magnetic domains tominimise Barkhausen noise
B-H granularity ! mg. domains sizeB-H granularity ! mg. domains size
DCCTs usage & limitations
52
To be used for precise DC current measurements
I measures everything: debunched, ghost and satellites,circulating beams
I due to feedback linear over 6 decades
I FS=〈10mA; 100A〉, resolution down to 1 µA, BW≤50 kHz
Calibration mostly using commercial DC current sources:
I Yokogawa GS200: accuracy ±0.03 % of setting + 5 µA
I Keithley 224: accuracy ±0.05 % of setting + 10 µA on 20 mA
Development heading to resolve:
I offset suppression & temp. dependence (≈ 5 µ A/K)
I material procurement
DCCT - material procurement is fancy stuff
53
H. Reeg: B-H curve measurements, Vitrovac 6025FH. Reeg: B-H curve measurements, Vitrovac 6025F
Vitrovac ordered with the same specification at different time.(VacuumSchmelze production technology didn’t change!)
Interesting study: MR sensors
54
Usage of magneto-resistance (GMR, AMR) andmagneto-impedance sensors to get the beam info: GSI novel-DCCT
Hape, M. et al., DIPAC2005Hape, M. et al., DIPAC2005
Beam currents in hundreds-A range, clip-on configuration
Invite you to see next talk by Wolfgang Vodel
Overview on Cryogenic Current Comparators for Beam Diagnostics
THANK YOU FOR YOUR ATTENTION
This presentation would not be possible without kind participation of manypeople around the world - thanks a lot:
P. Cameron, M. Heron, K. Scheidt, H. Reeg, D. Lipka, P. Forck, M. Wendt,A. Peters, M. A. Ibrahim, M. Wilinski, W. Vodel, P. Odier, S. Smith,
M. Ferianis, E. C. Deibele, M. Werner, K. Wittenburg
PART III
References used
Faraday cups
57
I Yu. Antipov et al.: “THE COMPACT FARADAY CUP FOR RADIOBIOLOGICAL RESEARCHES IN IHEPACCELERATORS BEAMS”, Institute for High Energy Physics, Protvino, Moscow region, Russia
I J. Harasimowicz, C. P. Welsch: “FARADAY CUP FOR LOW-ENERGY, LOW-INTENSITY BEAMMEASUREMENTS AT THE USR”, Cockcroft Institute, Warrington WA4 4AD, UK, and Department ofPhysics, University of Liverpool, Liverpool L69 7ZE, UK.
I T. Houck et al.: “FARADAY CUP MEASUREMENTS OF THE PLASMA PLUME PRODUCED AT ANX-RAY CONVERTER”, Lawrence Livermore National Laboratory, Livermore, California 94550 USA
I A.F.D. Morgan: “DESIGN OF THE FARADAY CUPS IN DIAMOND”, Diamond Light Source, UK
Wall Current Monitors
58
I T. Suwada et al.: “RECALIBRATION OF A WALL-CURRENT MONITOR USING A BEAM-INDUCEDFIELD FOR THE KEKB INJECTOR LINAC”, KEK, 1-1 Oho, Tsukuba-shi, Ibaraki-ken, 305, Japan
I A. D’Elia et al: “HIGH BANDWIDTH WALL CURRENT MONITOR FOR CTF3”, CERN, Geneva,Switzerland
I P. R. Cameron et al.: “THE RHIC WALL CURRENT MONITOR SYSTEM” , BNL, FNAL, USA
I A. D’Elia et at: “High Bandwidth Wall Current Monitor”, EUROTEV report, September 1, 2008
I C. D. Moore et al.: “Single Bunch Intensity Monitoring System Using an Improved Wall Current Monitor”,FERMI, USA
Fast Beam Current Transformers
59
I A. Burns et al.: “NOISE REDUCTION ON THE LEP BUNCH CURRENT MEASUREMENT SYSTEM”,CERN, CH–1211 Geneva 23, Switzerland
I Michael A. Clarke-Gayther: “A HIGH STABILITY INTENSITY MONITORING SYSTEM FOR THE ISISEXTRACTED PROTON BEAM”, RAL, Didcot, United Kingdom
I A. Higashiya et al.: “DEVELOPMENT OF A BEAM CURRENT TRANSFORMER FOR THE X-FELPROJECT IN SPRING-8”, SPring-8, JAPAN
I H. Reeg et al.: “CURRENT TRANSFORMERS FOR GSI’S KEV/U TO GEV/U ION BEAMS - ANOVERVIEW”, GSI, Germany
I M. Kesselman et al.: “BEAM CURRENT MONITOR CALIBRATOR FOR THE SPALLATION NEUTRONSOURCE”, Brookhaven National Laboratory, Upton NY 11973, USA
DCCTs
60
CARE-N3 EU sponsored workshop on DC current transformers, in particular:
I P. Odier: “DCCT TECHNOLOGY REVIEW”, CARE Workshop, Lyon, France
Intensity measurements talks
61
I Robert C. Webber: “Tutorial on Beam Current Monitoring”
I F. Gougnaud et al.: “THE FIRST STEPS OF THE BEAM INTENSITY MEASUREMENT OF THESPIRAL2 INJECTOR”, CEA, IRFU, SIS / Saclay, France
Other Intensity Measurements
62
I C. R. Rose et al.: “DESCRIPTION AND OPERATION OF THE LEDA BEAM-POSITION / INTENSITYMEASUREMENT MODULE”, Los Alamos National Laboratory, Los Alamos, NM 87545
I A.G.Afonin et al.: “WIDE RANGE EXTRACTED BEAM INTENSITY MEASUREMENT AT THE IHEP”,IHEP, Protvino, Russia
I R. Thirman-Keup et al.: “MEASUREMENT OF THE INTENSITY OF THE BEAM IN THE ABORT GAPAT THE TEVATRON UTILIZING SYNCHROTRON LIGHT”, FNAL, Batavia, IL 60510, USA
I P.-A. Duperrex et al.: “CURRENT AND TRANSMISSION MEASUREMENT CHALLENGES FOR HIGHINTENSITY BEAMS”, PSI, Villigen, Switzerland
I T.J. Ma et al.: “BUNCH-BY-BUNCH BEAM CURRENT MONITOR FOR HLS”, NSRL, School of NuclearScience and Technology, University of Science and Technology of China, Hefei 230029, P. R. China
I M. Dehler et al.: “STRIPLINE DEVICES FOR FLASH AND EUROPEAN XFEL”, PSI, Switzerland,DESY, Hamburg, Germany
I P. Moritz et al.: “Diamond Detectors with Subnanosecond Time Resolution for Heavy Ion SpillDiagnostics”, GSI, Germany
Squids / MR sensors
63
I T. Sieber et al.: “INTENSITY AND PROFILE MEASUREMENT FOR LOW INTENSITY ION BEAMS INAN ELECTROSTATIC CRYOGENIC STORAGE RING”, MPI-K Heidelberg, Germany
I M. Schwickert et al.: “BEAM DIAGNOSTIC DEVELOPMENTS FOR FAIR”, GSI, Darmstadt, Germany
I Markus Hape et al.: “HIGH DYNAMIC MAGNETIC BEAM CURRENT MEASUREMENTS BY MEANSOF OPTIMISED MAGNETO-RESISTANCE (MR) SENSOR ENGINEERING”, GSI Darmstadt, Germany
I W. Vodel et al.: “CURRENT STATUS OF THE SQUID BASED CRYOGENIC CURRENTCOMPARATOR FOR ABSOLUTE MEASUREMENTS OF THE DARK CURRENT OFSUPERCONDUCTING RF ACCELERATOR CAVITIES”, DESY Hamburg, Germany
I A. Peters et al.: “RECENT IMPROVEMENTS OF A CRYOGENIC CURRENT COMPARATOR FOR nAION BEAMS WITH HIGH INTENSITY DYNAMICS”, GSI, Darmstadt, Germany
I T. Watanabe et al.: “DEVELOPMENT OF BEAM CURRENT MONITOR WITH HTS SQUID AND HTSCURRENT SENSOR”, RIKEN Nishina Center for Accelerator-Based Science, Wako-shi, Saitama 351-0198Japan
I T.Tanabe et al.: “A CRYOGENIC CURRENT MEASURING DEVICE FOR THE LOW-INTENSITY BEAMAT THE STORAGE RING TARN II”, KEK, Tanashi, Tokyo, Japan
I T. Watanabe et al.: “DEVELOPMENT OF BEAM CURRENT MONITOR WITH HIGH-Tc SQUID ATRIBF”, RIKEN Nishina Center for Accelerator-Based Science, Wako-shi, Saitama 351-0198, Japan
PART IV
Extras
Intensity measurements during LHC orbit bump
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×1011 LHC Beam 2 Intensity measurement during the orbit bump
DCCTFBCT, varies by ≈1 %/mm with respect to the DCCT
≈1 %/mm bunch position dependency of the FBCT toroid
0 200 400 600 800 1000 1200 1400 1600
t [s]
7.7
7.8
7.9
8.0
8.1
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mIn
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ity[-]
×1011 LHC Beam 2 Intensity measurement during the orbit bump
DCCTFBCT, varies by ≈1 %/mm with respect to the DCCT
≈1 %/mm bunch position dependency of the FBCT toroid