UM PPS Lab ActivitiesMid-size Panel Tests

PPS meeting January 15, 2012Claudio, Curtis, Dan, Ethan, Riley

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MP1 Tests

January 15, 2013

• Panel re-baked over night at 100⁰C nd filled with 90%Ar 10%CF4 at 600 Torr December 18, 2012.

• 13 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-SnO2 with line pitch 1mm, with the high numbered channels toward R-quench

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Initial Voltage Scans

January 15, 2013

Top two plot scans with lights ON- left HV always ON- right 1’ off before runThe panel is light sensitive!From next test on, all runs undera cardboard boxAt 880V Rate(Bkg)~Rate(Src)!

WorkingRegion

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Uniformity Scan – Many Voltages

January 15, 2013

The two position are different by 10 mm toward the low numbered channels

RESULT#1) Very Low background RESULT#2) Hit map substantially flatRESULT#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!)

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Uniformity Scan – 3 Positions

January 15, 2013

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)

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Position Scan Un-collimated

January 15, 2013

Gaussian fit ±8 bins around the max(First 3 runs eliminated, fit too poor at the edge)

Source moved by 2mm/run

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Position Scan Un-collimated Results

January 15, 2013

As in the Uniformity Scan, thenumber of event for higher numbered channel is larger

Slope = 1/pitchFit result not compatible with the hardware value 1 mm

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Long Uniformity Scan

January 15, 2013

This hit map gives channel by channel response correct ion factors respect to uniform distribution

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Channel Response

January 15, 2013

Relevant -20% +25%, with a few jumps between nearby channels!

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Hourly Hit Map

January 15, 2013

Limited difference It seems stable

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Normalized Hourly Hit Map

January 15, 2013

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Uniformity in Time

January 15, 2013

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 thepanel (SnO2) degradation or is it just an initial effect?

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Hourly Rate

January 15, 2013

The rate decrease doesnot seems to stabilize Later as in the first test

Weekend long run

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Hourly Channel Rate

January 15, 2013

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

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Hourly Correction Variation

January 15, 2013

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Position Scan Collimated

January 15, 2013

Movement every 1 mmNew fit function Gaussian + Linear over then whole range

A few runs eliminated(edge effect)

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Fit of the Mean Fit

January 15, 2013 UM PPS Activities

The quadratic fit has a better reduced χ2 than the simple linear function and the slope is close to 1. But why ?

Not OK

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Fine Position Scan Collimated• 72 runs with source moved by 0.25 mm each time

January 15, 2013

The correction makesthe peak amplitudemore stable!

Before and after correcting channel by channel the hit maps

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Lin Vs Quad Fit of the Mean Fit

January 15, 2013

Once more the quadratic fit has a much better χ2/#dof than the linear function

In both cases the slope is far from 1by many time the error on the fit

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Lin Vs Quad Fit of the Mean Fit (2)

January 15, 2013

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.

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ConclusionsA 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%CF4 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, 2013

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Conclusion (2)• Ethan & Riley contributed on taking the scan runs• Cabinet with doors to shield the Ni-SnO2 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, 2013