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Target Operations. A summary of Target Operation to Date Paul Hodgson The University of Sheffield . T1 Operation Dates. DAQ Timing Problem. Calibrations Taken. Target Parameters. Start position: x 1 Start time: t 1 Time beam on:TB 1 Time beam off:TB 2 BCD minimum:x 2 - PowerPoint PPT Presentation
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Target Operations
A summary of Target Operation to DatePaul Hodgson
The University of Sheffield
T1 Operation Dates
DAQ Timing Problem
Calibrations Taken
Shift Purpose Date N PulsesElectronics commissioning From 28-Aug 620
Beamloss/BCD scan 05-Sep 5364Beamloss/BCD scan plus delay 06-Sep 5819
50 Hz operation tests 08-Sep 1467
Beamline commissioning - 2V BL test 10-Sep 73331V beamloss for radiation survey 12-Sep 14644
Beamline commissioning - DAQ debugging 16-Sep 3218DAQ debugging 23-Sep 459
Beamline commissioning 25-Sep 1129Beamline commissioning 27-Sep 3465
Beamline commissioning 29-Sep 3818
Beamline commissioning 01-Oct 2549Beamline commissioning 03-Oct 5859
Beamline commissioning 04-Oct 6833Beamline commissioning 05-Oct 2150
Beamline commissioning 05-Nov 1920Beamline commissioning 06-Nov 2822
Beamline commissioning 07-Nov 5630Beamline commissioning 11-Nov 2178
DAQ commissioning 17-Nov 1906
TOF Calibration 18-Nov 2584TOF Calibration 02-Dec 2972
TOF Calibration 04-Dec 5946Emittance Measurements 07-Dec 5590
Emittance Measurements/TOF calibration 10-Dec 5582Emittance Measurements/TOF calibration 11-Dec 6152
108009
Target Parameters
Start position: x1
Start time: t1
Time beam on: TB1
Time beam off: TB2
BCD minimum: x2
Time BCD minimum: t2
Strike: s = x2 – x1
Strike time: t = t2 – t1
Acceleration: a = 4s/t2
Run reduction code over the raw data to parameterise
Can then plot interesting variables quickly
Interesting Parameters include
Target hold positionTarget BCD – Beam Centre DistanceTarget Acceleration
TB1 TB2
x1
x2
t1 t2
Target Hold Position
1 hour
Takes about 2 hours to warm up
2 populations a result of capture mechanism
Target BCD
Steering target into/out of beam
Stable running
Decreased BCD to increase particle rate
Target Acceleration
Takes about 2 hours to warm up
Rapid change – Ohmic heating of coils
Slower decrease over 2+ hours
Target Acceleration
Takes about 2 hours to warm up
Lots of stopping and starting
BCD HistogramsHistogram BCDs for a set value
Clear difference between the two distributions
Failing target has a much broader spread
T2 distribution 3-4 times as broad
Can be interpreted as a result of the target “sticking”
BCDs for T1 and T2In each case the test runs were setup to pulse with a nominal BCD of 19-20 mm
Very different appearance for BCD time series plots for T1 and T2
T1 very stable BCD does not vary over time
T2 BCD varies strongly over time
Plot very “spiky” after ~42k pulses
Clear signal for target failure
T2 Commissioning Run
Calibration Histograms
Fit double Gaussian to BCD by hand Why ?
Trying to account for second population usually seen
Calibration Histograms
Tricky to automate, usually need to tweak the fit start values by hand to get the fit to converge
Obvious 2nd peak More ambiguous case
Is it better to simply fit a single gaussian or do no fit at all and use RMS ?
Another view of the Calibration
Double Gaussian fitcan pick out second population and gives better resolution for spread
BCD Calibrations to date
All within narrow range ~ 0.6mm
No discernable changeover time
Conclusions
• Have a simple method of spotting potential breakdown of the target
• Target performance looks fine to date• This method is partially automated in current
target DAQ – Thanks James • Still needs an “experts eye”• Don’t want to define some arbitrary failure value
until we see how these measurements evolve