UM PPS Lab Activities Midsize Panel Tests PPS

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

MP 1 Tests • Panel re-baked over night at 100⁰C nd filled with 90%Ar 10%CF 4 at 600 Torr December 18, 2012. • 13 HV lines at 100 MΩ + 20 RO lines (attenuation~9. 4), discriminated at -150 m. V, 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-Sn. O 2 with line pitch 1 mm, with the high numbered channels toward R-quench January 15, 2013 UM PPS Activities 2

Initial Voltage Scans 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 880 V Rate(Bkg)~Rate(Src)! January 15, 2013 UM PPS Activities Working Region 3

Uniformity Scan – Many Voltages 865 V data bad (to be fixed!) 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 870 V January 15, 2013 UM PPS Activities 4

Uniformity Scan – 3 Positions Pos 2= Pos 1 + 5 mm Pos 3= Pos 1 - 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) January 15, 2013 UM PPS Activities 5

Position Scan Un-collimated Source moved by 2 mm/run Gaussian fit ± 8 bins around the max (First 3 runs eliminated, fit too poor at the edge) January 15, 2013 UM PPS Activities 6

Position Scan Un-collimated Results As in the Uniformity Scan, the number of event for higher numbered channel is larger Slope = 1/pitch èFit result not compatible with the hardware value 1 mm January 15, 2013 UM PPS Activities 7

Long Uniformity Scan This hit map gives channel by channel response correct ion factors respect to uniform distribution January 15, 2013 UM PPS Activities 8

Channel Response Relevant -20% +25%, with a few jumps between nearby channels! January 15, 2013 UM PPS Activities 9

Hourly Hit Map Limited difference It seems stable January 15, 2013 UM PPS Activities 10

Normalized Hourly Hit Map January 15, 2013 UM PPS Activities 11

Uniformity in Time 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 (Sn. O 2) degradation or is it just an initial effect? January 15, 2013 UM PPS Activities 12

Hourly Rate The rate decrease does not seems to stabilize Later as in the first test January 15, 2013 Weekend long run UM PPS Activities 13

Hourly Channel Rate 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 January 15, 2013 UM PPS Activities 14

Hourly Correction Variation January 15, 2013 UM PPS Activities 15

Position Scan Collimated Movement every 1 mm New fit function Gaussian + Linear over then whole range A few runs eliminated (edge effect) January 15, 2013 UM PPS Activities 16

Fit of the Mean Fit Not OK The quadratic fit has a better reduced χ2 than the simple linear function and the slope is close to 1. But why ? January 15, 2013 UM PPS Activities 17

Fine Position Scan Collimated • 72 runs with source moved by 0. 25 mm each time Before and after correcting channel by channel the hit maps The correction makes the peak amplitude more stable! January 15, 2013 UM PPS Activities 18

Lin Vs Quad Fit of the Mean Fit Once more the quadratic fit has a much better χ2/#dof than the linear function In both cases the slope is far from 1 by many time the error on the fit January 15, 2013 UM PPS Activities 19

Lin Vs Quad Fit of the Mean Fit (2) 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. January 15, 2013 UM PPS Activities 20

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 860 V • Uniformity Scan: MP 1 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 870 V to be analyzed to see any voltage effect • We have more results than what has been presented here. . . January 15, 2013 UM PPS Activities 21

Conclusion (2) • Ethan & Riley contributed on taking the scan runs • Cabinet with doors to shield the Ni-Sn. O 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 DT 5472 default software is only an example of DAQ, we need to invest time/effort to have a solid code for taking data January 15, 2013 UM PPS Activities 22