Target Operations A summary of Target Operation to Date Paul Hodgson The University of Sheffield

T1 Operation Dates DAQ Timing Problem Calibrations Taken Shift PurposeDateN Pulses Electronics commissioningFrom 28-Aug620 Beamloss/BCD scan05-Sep5364 Beamloss/BCD scan plus delay06-Sep Hz operation tests08-Sep1467 Beamline commissioning - 2V BL test10-Sep7333 1V beamloss for radiation survey12-Sep14644 Beamline commissioning - DAQ debugging16-Sep3218 DAQ debugging23-Sep459 Beamline commissioning25-Sep1129 Beamline commissioning27-Sep3465 Beamline commissioning29-Sep3818 Beamline commissioning01-Oct2549 Beamline commissioning03-Oct5859 Beamline commissioning04-Oct6833 Beamline commissioning05-Oct2150 Beamline commissioning05-Nov1920 Beamline commissioning06-Nov2822 Beamline commissioning07-Nov5630 Beamline commissioning11-Nov2178 DAQ commissioning17-Nov1906 TOF Calibration18-Nov2584 TOF Calibration02-Dec2972 TOF Calibration04-Dec5946 Emittance Measurements07-Dec5590 Emittance Measurements/TOF calibration10-Dec5582 Emittance Measurements/TOF calibration11-Dec

Target Parameters Start position:x 1 Start time:t 1 Time beam on:TB 1 Time beam off:TB 2 BCD minimum:x 2 Time BCD minimum:t 2 Strike:s = x 2 – x 1 Strike time:t = t 2 – t 1 Acceleration:a = 4s/t 2 Run reduction code over the raw data to parameterise Can then plot interesting variables quickly Interesting Parameters include Target hold position Target BCD – Beam Centre Distance Target Acceleration TB 1 TB 2 x1x1 x2x2 t1t1 t2t2

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 Histograms Histogram 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 T2 In each case the test runs were setup to pulse with a nominal BCD of 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 handWhy ? 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 2 nd peakMore 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 fit can pick out second population and gives better resolution for spread

BCD Calibrations to date All within narrow range ~ 0.6mm No discernable change over 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