Difference between revisions of "Run1 - January 2015"
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| − | = Shift Schedule = | + | = Shift Responsibilties = |
| + | |||
| + | == Schedule == | ||
[[File:140112_shifts.png|thumb|center|300px]] | [[File:140112_shifts.png|thumb|center|300px]] | ||
| − | = | + | == Duties == |
; Beam Driver | ; Beam Driver | ||
Beam setup: gun + laser + spin + beam to Mott | Beam setup: gun + laser + spin + beam to Mott | ||
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Elastic events counted for IHWP=IN/OUT | Elastic events counted for IHWP=IN/OUT | ||
| − | = Prep Work (through Tuesday Jan 13) = | + | =Experiment Goals and Plans= |
| + | == Prep Work (through Tuesday Jan 13) == | ||
#Make a photocathode – SL5247-1 made | #Make a photocathode – SL5247-1 made | ||
#Test IHA2D00 – wires & stroke good, but data file odd vs. others | #Test IHA2D00 – wires & stroke good, but data file odd vs. others | ||
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#Build qsUtility config file –documented below | #Build qsUtility config file –documented below | ||
| − | = Injector Setup and Mott Checkout (Wed Jan 14 - Fri Jan 16) = | + | == Injector Setup and Mott Checkout (Wed Jan 14 - Fri Jan 16) == |
#Restore beam to FC2 @ 6.3 MeV/c | #Restore beam to FC2 @ 6.3 MeV/c | ||
#Mott test: DAQ FADC/TDC synchronization | #Mott test: DAQ FADC/TDC synchronization | ||
| Line 41: | Line 44: | ||
#Calibrate BCM to FC2 | #Calibrate BCM to FC2 | ||
| − | = Mott Setup and Systematics Testing (Sat Jan 17) = | + | == Mott Setup and Systematics Testing (Sat Jan 17) == |
#Setup good orbit to Mott | #Setup good orbit to Mott | ||
#Set PMT HV | #Set PMT HV | ||
| Line 56: | Line 59: | ||
#Measure asymmetry vs. energy spread | #Measure asymmetry vs. energy spread | ||
| − | = Target Foil Extrapolation (Sat Jan 17 - Mon Jan 19) = | + | == Target Foil Extrapolation (Sat Jan 17 - Mon Jan 19) == |
; 14 foils to study + 1 thru hole | ; 14 foils to study + 1 thru hole | ||
spectra – with typical low ~2 MeV energy threshold | spectra – with typical low ~2 MeV energy threshold | ||
| Line 72: | Line 75: | ||
; [[File:140112_runtimes.png|center]] | ; [[File:140112_runtimes.png|center]] | ||
| − | = How to measure emittance = | + | =Procedures= |
| + | |||
| + | == How to measure emittance == | ||
; Beam Setup | ; Beam Setup | ||
We measure the beam emittance and Twiss at entrance of MQJ0L02 by varying MQJ0L02 and observing response on harp IHA0L03 | We measure the beam emittance and Twiss at entrance of MQJ0L02 by varying MQJ0L02 and observing response on harp IHA0L03 | ||
| Line 100: | Line 105: | ||
Use the BL calculation on the control screen of MDL0L02 | Use the BL calculation on the control screen of MDL0L02 | ||
| − | = How to use Elegant files = | + | == How to use Elegant files == |
Revision as of 15:11, 12 January 2015
Shift Responsibilties
Schedule
Duties
- Beam Driver
Beam setup: gun + laser + spin + beam to Mott BCM & target motion FSDs enabled Vacuum levels reasonable Magnet and RF setup saved PITA adjusted for IHWP IN/OUT
- DAQ Driver
Start/Stop DAQ entering correct run information Monitor event rates and maintain dead time <5% Coordinate run start/stop with Beam and Analysis Drivers
- Analysis Driver
Runs decoded, analyzed and promptly inspected Run # and information logged onto run sheets Elastic events counted for IHWP=IN/OUT
Experiment Goals and Plans
Prep Work (through Tuesday Jan 13)
- Make a photocathode – SL5247-1 made
- Test IHA2D00 – wires & stroke good, but data file odd vs. others
- Hi-Pot IP – FE’r potted, but high again, vac readback not good
- CHL 2K cooldown – maybe early, Monday Jan 12th
- Install laser – Tue or Wed
- Test laser RF trigger – after laser installed (1V, 10ns @ RF)
- Verify beam line layout –documented below
- Build elegant deck – working
- Build qsUtility config file –documented below
Injector Setup and Mott Checkout (Wed Jan 14 - Fri Jan 16)
- Restore beam to FC2 @ 6.3 MeV/c
- Mott test: DAQ FADC/TDC synchronization
- Mott test: event separation and transmission at 62MHz acceptable
- Quad center BPMs for momentum measurement
- Test harp IHA2D00 if ready for energy spread measurement
- Scale cryounit for p=5.487 MeV/c and minimize energy spread
- Precisely measure beam momentum
- Measure beam emittance
- Measure energy spread
- Calibrate BCM to FC2
Mott Setup and Systematics Testing (Sat Jan 17)
- Setup good orbit to Mott
- Set PMT HV
- Set PMT energy thresholds
- Set polarization vertically
- Calibrate PITA vs IHWP IN/OUT
- Finalize orbit w/ instrumental asymmetry, TOF and spectra
- Adjust target offsets per vertical instrumental asymmetry
- Measure dump rate fraction to determine run times
- Measure dead-time vs. rate
- Measure asymmetry vs. beam current
- Measure asymmetry vs. time (stability)
- Measure asymmetry vs. spot size
- Measure asymmetry vs. energy spread
Target Foil Extrapolation (Sat Jan 17 - Mon Jan 19)
- 14 foils to study + 1 thru hole
spectra – with typical low ~2 MeV energy threshold statistics – possibly higher ~3 MeV threshold to reduce dump events
- Deadtime
Semi-int mode we use w/ FADC/TDC/scalar is ~5% @ 1500 Hz
- Inelastic fraction
Worst case ~200 Hz/det (best case ~25 Hz/det) Energy threshold will be defined to set this value Time veto is tricky and too risky at 62 MHz
- Assuming I=5uA, R<1500Hz, 200Hz/det background
28 hours * 1.2 / 8 = 4-5 shifts dP/P sets N_elastic (using 1σ analysis cut of all 4 det) Measurement of of inelastic (dump) events figures into run time
Procedures
How to measure emittance
- Beam Setup
We measure the beam emittance and Twiss at entrance of MQJ0L02 by varying MQJ0L02 and observing response on harp IHA0L03 To simplify matters we turn off the intervening quadrupoles (MQJ0L02A = MQJ0L03A =MQJ0L03 = 0) Obviously, make sure beam can transports from MQJ0L02 to IHA0L03 w/ those quads off (use BPM's and viewers) The configuration changes MQJ0L02 B for 21 K1 values (-3.0, -3.2, … , -5.8, -6.0); this takes ~45 minutes, so a smaller data set could be used too
- qsUtility
We use program named qsUtility to automatically to make the measurements and analyze the data The measurement configuration file is here and can also be used as a template /cs/prohome/apps/q/qsUtility/pro/fileio/config/IHA0L03_jmg1.xml qsUtility is documented here
- qsUtility assumes v=c
One must scale the Energy [MeV] entry box as the tool uses this formula B'L [G] = K1[1/m^2] * L[m] * E[MeV] * 10/0.2998
How to measure momentum
- Before using absolute BPM's perform centering procedure to adjacent quadrupoles
MQJ0L02 = IPM0L02 MQJ0L03 = IPM0L03 MQD5D00 = IPM5D00 MQD5D01 = IPM5D01 Mike Spata suggests standard dithering, as we do for solenoids When complete update the BPM .SOF field and log result
- Beam steering
Earth’s field is likely too strong to turn zero intervening correctors Excite minimum number of correctors and record values p = sqrt [T*(2m+T)] so T = 5.0 MeV => p 5.487 MeV/c Check me: dT/T = (T+2m)/(T+m) * dp/p so dT/T=1.09 * dp/p @ T=5.0 Use the BL calculation on the control screen of MDL0L02