UM PPS Lab Activities Mid-size Panel Tests PPS meeting January 15, 2012 Claudio, Curtis, Dan, Ethan, Riley

MP1 Tests January 15, 2013UM PPS Activities2 Panel re-baked over night at 100⁰C nd filled with 90%Ar 10%CF 4 at 600 Torr December 18, HV lines at 100MΩ + 20 RO lines (attenuation~9.4), discriminated at -150mV, to the Wiener 20 channels counter (the other 4 lines of the RO card are masked) Three types of test: – Voltage Scan, with/without Source at fixed R-quench – Position Scan: (un)collimated source moved across RO lines – Uniformity: un-collimated source at 19 cm above the panel  uniform spray of betas over the instrumented region Remember: This panel is Ni-SnO 2 with line pitch 1mm, with the high numbered channels toward R-quench

Initial Voltage Scans January 15, 2013UM PPS Activities3 Top two plot scans with lights ON - left HV always ON - right 1’ off before run The panel is light sensitive! From next test on, all runs under a cardboard box At 880V Rate(Bkg)~Rate(Src)! Working Region

Uniformity Scan – Many Voltages January 15, 2013UM PPS Activities4 The two position are different by 10 mm toward the low numbered channels RESULT#1) Very Low background RESULT#2) Hit map substantially flat RESULT#3) Rate scale with Voltage (if the bkg remains low!) RESULT#4) The rate on the second scan is much lower at 870V 865V data bad (to be fixed!)

Uniformity Scan – 3 Positions January 15, 2013UM PPS Activities5 Pos2= Pos1 + 5 mm Pos 3= Pos1 - 5 mm In all cases, there is an increases for channel #1 and for the higher numbered channels (#19 is less responsive of the nearby ones)

Position Scan Un-collimated January 15, 2013UM PPS Activities6 Gaussian fit ±8 bins around the max (First 3 runs eliminated, fit too poor at the edge) Source moved by 2mm/run

Position Scan Un-collimated Results January 15, 2013UM PPS Activities7 As in the Uniformity Scan, the number of event for higher numbered channel is larger Slope = 1/pitch  Fit result not compatible with the hardware value 1 mm

Long Uniformity Scan January 15, 2013UM PPS Activities8 This hit map gives channel by channel response  correct ion factors respect to uniform distribution

Channel Response January 15, 2013UM PPS Activities9 Relevant -20% +25%, with a few jumps between nearby channels!

Hourly Hit Map January 15, 2013UM PPS Activities10 Limited difference  It seems stable

Normalized Hourly Hit Map January 15, 2013UM PPS Activities11

Uniformity in Time January 15, 2013UM PPS Activities12 Is the performance (hit rate) of the panel constant in time? The quadratic fit works better  the hit rate is not constant, it decreases in time! Is this a measurement of the panel (SnO 2 ) degradation or is it just an initial effect?

Hourly Rate January 15, 2013UM PPS Activities13 The rate decrease does not seems to stabilize Later as in the first test Weekend long run

Hourly Channel Rate January 15, 2013UM PPS Activities14 Analysis in progress: it will be interesting to see if the decrease rate trend is the same for all the channels or higher for the more responsive

Hourly Correction Variation January 15, 2013UM PPS Activities15

Position Scan Collimated January 15, 2013UM PPS Activities16 Movement every 1 mm New fit function Gaussian + Linear over then whole range A few runs eliminated (edge effect)

Fit of the Mean Fit January 15, 2013UM PPS Activities17 The quadratic fit has a better reduced χ 2 than the simple linear function and the slope is close to 1. But why ? Not OK

Fine Position Scan Collimated 72 runs with source moved by 0.25 mm each time January 15, 2013UM PPS Activities18 The correction makes the peak amplitude more stable! Before and after correcting channel by channel the hit maps

Lin Vs Quad Fit of the Mean Fit January 15, 2013UM PPS Activities19 Once more the quadratic fit has a much better χ 2 /#dof than the linear function In both cases the slope is far from 1 by many time the error on the fit

Lin Vs Quad Fit of the Mean Fit (2) January 15, 2013UM PPS Activities20 Now the pure linear function fits better the data, but the slope is still far from the unity Now the quadratic function fits quite well the data, and the slope is not too far from the unity.

Conclusions A lot of new data on the Mid-size panel. It responded very nicely! Significant photo-sensitivity forced us to cover the panel Voltage Scan: with 90%Ar 10%CF 4 at 600 Torr and quench resistor 100 MΩ the working region is limited around 860V Uniformity Scan: MP1 has channel by channel different response  correction deduced from a long run Long Uniformity Scan: the acquisition rate is not exactly linear, but it tends to slowly decrease in time. The very long run over the weekend will allow to better check rate (and corrections) stability Position Scans: thanks to the corrections the data seems better, but the correlation of the source Vs reconstructed position seems to be more slightly quadratic than linear. Even with small source movements we were not able to see the inter-strip spaces (drop in the acquisition rate, broader peak distribution...). We have also a new position scan at 870V to be analyzed to see any voltage effect We have more results than what has been presented here... January 15, 2013UM PPS Activities21

Conclusion (2) Ethan & Riley contributed on taking the scan runs Cabinet with doors to shield the Ni-SnO 2 panels from the lights is ready to be installed Progress on the gas mixing station leak fixing and on starting our gas chromatography (Curtis and Riley) The CAEN DT5472 default software is only an example of DAQ, we need to invest time/effort to have a solid code for taking data January 15, 2013UM PPS Activities22