Objectives Determine Detector offsets in hall B
reference frame and thus absolute beam position at Hycal
Examine Flux calculation and see if beam trips can be eliminated more effectively by changing parameters within existing software
Beam PositionMathew Reece amp Dustin Woolford
Beam Position Ideally to find the absolute beam position two
BPMs can be used and then offsets determined from the projection of that line to other detectors
However there is a magnetic field present between the two BPMs in hall B Is it negligible
There is a single run (4943) where the beam position is known to change abruptly midway through the run at BPM1 and at Hycal but very little at BPM2
Whats known BPM data suggests that readouts are in the
hall B frame HYCAL x = 002 mm beam right y = 009
mm high relative to CLAS center line Gamma Profiler needs to be determined
Linearity By using only data from (4349)
the unknown detector offsets do not affect the calculations
We assume that the beam is linear between the BPMs and compare every other event in the run with the first event
The angles are determined by the arctangent of the difference between the measured points on a detector for the first event and a later event divided by the distance between that detector and BPM 2 As shown on the previous slide α1 is for BPM 1 and α2 is for the γ profiler
By our conventions the ratio α2α1 will be -1 if the beam is linear [since arctan x = -arctan (-x)]
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Beam PositionMathew Reece amp Dustin Woolford
Beam Position Ideally to find the absolute beam position two
BPMs can be used and then offsets determined from the projection of that line to other detectors
However there is a magnetic field present between the two BPMs in hall B Is it negligible
There is a single run (4943) where the beam position is known to change abruptly midway through the run at BPM1 and at Hycal but very little at BPM2
Whats known BPM data suggests that readouts are in the
hall B frame HYCAL x = 002 mm beam right y = 009
mm high relative to CLAS center line Gamma Profiler needs to be determined
Linearity By using only data from (4349)
the unknown detector offsets do not affect the calculations
We assume that the beam is linear between the BPMs and compare every other event in the run with the first event
The angles are determined by the arctangent of the difference between the measured points on a detector for the first event and a later event divided by the distance between that detector and BPM 2 As shown on the previous slide α1 is for BPM 1 and α2 is for the γ profiler
By our conventions the ratio α2α1 will be -1 if the beam is linear [since arctan x = -arctan (-x)]
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Beam Position Ideally to find the absolute beam position two
BPMs can be used and then offsets determined from the projection of that line to other detectors
However there is a magnetic field present between the two BPMs in hall B Is it negligible
There is a single run (4943) where the beam position is known to change abruptly midway through the run at BPM1 and at Hycal but very little at BPM2
Whats known BPM data suggests that readouts are in the
hall B frame HYCAL x = 002 mm beam right y = 009
mm high relative to CLAS center line Gamma Profiler needs to be determined
Linearity By using only data from (4349)
the unknown detector offsets do not affect the calculations
We assume that the beam is linear between the BPMs and compare every other event in the run with the first event
The angles are determined by the arctangent of the difference between the measured points on a detector for the first event and a later event divided by the distance between that detector and BPM 2 As shown on the previous slide α1 is for BPM 1 and α2 is for the γ profiler
By our conventions the ratio α2α1 will be -1 if the beam is linear [since arctan x = -arctan (-x)]
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Whats known BPM data suggests that readouts are in the
hall B frame HYCAL x = 002 mm beam right y = 009
mm high relative to CLAS center line Gamma Profiler needs to be determined
Linearity By using only data from (4349)
the unknown detector offsets do not affect the calculations
We assume that the beam is linear between the BPMs and compare every other event in the run with the first event
The angles are determined by the arctangent of the difference between the measured points on a detector for the first event and a later event divided by the distance between that detector and BPM 2 As shown on the previous slide α1 is for BPM 1 and α2 is for the γ profiler
By our conventions the ratio α2α1 will be -1 if the beam is linear [since arctan x = -arctan (-x)]
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Linearity By using only data from (4349)
the unknown detector offsets do not affect the calculations
We assume that the beam is linear between the BPMs and compare every other event in the run with the first event
The angles are determined by the arctangent of the difference between the measured points on a detector for the first event and a later event divided by the distance between that detector and BPM 2 As shown on the previous slide α1 is for BPM 1 and α2 is for the γ profiler
By our conventions the ratio α2α1 will be -1 if the beam is linear [since arctan x = -arctan (-x)]
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Important note It is important to verify
that the beam position on BPM 2 does not vary significantly in order for this method to be valid As the graph shows the location where the beam passes through BPM 2 does not move more than 02 mm during the run
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Now that the constancy of BPM 2 has been verified let us look at the α2α1 ratio
Ratio of Change in Beam Angles for run 4349
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 60000 120000 180000 240000 300000
Event
Ra
tio
Ratio
Ideal Ratio
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Determining offsets A Java program that will use BPM2 and Hycal to
determine (xy) at the gamma profiler is written Average offsets for each run must be determined
and then entered into the MySQL database The same program must be re run for BPM2 and
Gamma Profiler to determine (xy cos(x) cos(y) Yet to be completed
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
LuminosityDustin Woolford
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
General Idea Tagged Yield = Cross Section x target thickness x
solid angle x Nγ tagged (exp) Nγ tagged (exp) = Ne (exp) x Tagging ratio Tagging ratio = Nγ tagged (cal) Ne (cal) Given a Tagged yield target thickness solid angle
and the flux the Pi0 cross section can be extracted
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Flux Nγ tagged (exp)
(Flux) Tagged photons per run per T channel Nγί = Neί x Rί where N and R are the number of electrons per T
channel and the tagging ratio respectively Rί is determined during the TAC runs
Neί = ( ηeί w x ηtrigs) x live 1
- ηeί = e- in a T channel in a given window
- w = size of the TDC window
- ηtrigs = of trigger events
Basically average e- rate for a T channel x live time
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Live Time of DAQ Dead time = Live 1 Live 2 Both Live 1 and Live 2 are driven by a 195316 +-
00045 kHz internal clock Live 1 is gated Live 2 is free TDC start is attached to the tagger and the stop is
initiated by a Pi0 event Trigger is also activated by a Pi0 event in hycal There is a 25 ns internal dead time for the TDC separate
from the trigger dead time Donrsquot need to correct for dead time because only tagged
Pi0 event go to elastic scattering
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Considerations Two types of tagging ratios
1) Absolute ndash uses lead glass solid block and is assumed to have 100 efficiency at low photon intensities (TAC)
- given by Rabs = N γTAC e- Ne-
2) Relative ndash uses the pair spectrometer to monitor the tagging ratio during runs but has 006 efficiency
-given by Rrel = N pse+e- - e- Ne-
Method 1 must be used to calibrate 2
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Considerations contrsquod Effects that may reduce the Absolute tagging ratio
from 1 three primary factors1) photon is produced but absorbed before reaching the TAC ( effect is reduced by helium baghellipbut not corrected for )
2) electron decelerates in the target without producing a photon 3) extra electrons in the tagger (effect gets large at high beam intensities so Rrel must be corrected for )
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Corrections (brief list non-exhaustive) Relative tagging ratio has back ground that
must be accounted for (background = Integral of events w)
Rrel is intensity independent at the at low beam intensity ( 01 ndash 100 nA
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Corrections contrsquod To correct for dependence at high beam intensity the relative
tagging ratio per T counter was averaged for all runs Then for each affected run Rrel was normalized to its corresponding average per T counter
Collimators 86 mm and 127 mm were found to cut 4 and 1 of the beam respectively
Run to run stability ( good up to run 5100) Live time problem ( implemented algorithm to solve )
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Tagger Detector Rate 3 ways ( Integral exponential and Poisson method) Integral is primary means The time distribution is integrated over a range which
excludes the triggering events and depletion from LIFO limits The integral is divided by the product of integration interval and of events over which the distribution was accumulated (Aramrsquos luminosity monitoring Primex notes)
Independent of TDC dead time due to using Live 1 Can be used for high and low rate detectors Tosses a lot of data and abstract coincidence detectors are
affected subtly by the LIFO limit and dead time
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Pflux package Prim_ana has Pflux package that links data analysis with the luminosity Attempts to identify and eliminate beam trips Run is pre-segmented into 5 second intervals Pflux Uses the integral
method to calculate tagging rate and live time for each segment Averages live time for all segments and fits Gaussian to the ldquoavg
histogramrdquo Identifies everything outside 3 σ as a beam trip cuts 2 five second intervals following identified beam trip Configurations
- beam_trip activates beam trip cuts - num_bad of 5 second intervals cut after beam trip- livetime_sigma number of standard deviations that contain ldquogoodrdquo data
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
Live Time Study ( courtesy of Eric Clinton and Aram Teymurazyan)
Uses Pflux package to output flux per run per T channel per E channel live time and average flux and live time for each run
Standalone from prim_ana Use Root and excel to graph flux as a
function of sigma and of cut intervals
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
flux vs sigma
0
05
1
15
2
25
3
35
0 2 4 6 8
varied sigma
tota
l F
lux
avg
li
ve t
ime
5003
498850505059
4981
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)
fluxlive t vs number of intervals cut
y = -02219x + 29384
y = -00139x + 20943
y = 0011x + 10802
0
05
1
15
2
25
3
0 2 4 6
of intervals cut after identified beam trip
flu
x l
ive
t
4981
5003
4988
Linear (4988)
Linear (5003)
Linear (4981)