Status report Dec 7 Yiftah Silver Dan Levin December 7 2010 1 Hardware progress We have managed to connect both DRS4 boards to the panel 4 RO channels and 4 HV channels at the same time ID: 217291
Download Presentation The PPT/PDF document "UM lab activity" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
UM lab activity
Status report Dec. 7
Yiftah Silver, Dan Levin
December 7, 2010
1Slide2
Hardware progress
We have managed to connect both DRS4 boards to the panel.4 RO channels and 4 HV channels at the same time.
A 4X4 array of pixels is available for measurements – a 2D detector.Same connectors as last week. Slide3
R
out=100[Ohm]
Yiftah Silver, Dan Levin
11/30/2010
3
HV
R
q
=22MOhm
SnO
2
Attenuators:
For HV line:20dB &inverter
For RO line 20dB+20dB
Ni
Set-Up
C
HV
=2pf
2 DRS4 boards
Discrimination threshold:
For
RO lines: -
0.5V
DRS4 trigger
Common trigger – OR on all RO channelsSlide4
Bkg measurements
A measurement of hit rate over time was made on one pixel (12X30) with the LabView program and the scope.
The measurement is of RO line 12 after a (10X attenuator).24 consecutive hit rate measurements were made, each 15 min long – total of 6 hours.Slide5
Hit rate over time (12X30)Slide6
From the same measurement:
Rise time distribution is obtained by subtracting the time of the point 10% of the peak from 90% of the peak, without any fits.Slide7
Few hits were at -20VSlide8
Measurements on 4X4 array
A set of measurements were made with the DRS4 boards.3 min measurement of bkg
Followed by a measurement when the collimated Sr90 is above the 4 center pixels.
Pulse height distributions were made for each pixel separately at each of the conditions.“Lego” plots were made for visualization.Slide9
Measurements on 4X4 array
PV1 99%Ar- 1%CF4 700 Torr , 850VSlide10
Subtraction of the
bkg from the source
The source is clearly seen in the center of the array of pixelsSlide11
Pulse height distribution 4x4
bkg
X axis – mV (this is after 2 attenuators X10 each)
Shown here are pixels (10,11)X(29,30)Slide12
Pulse height distribution 4x4
bkg
X axis – mV (this is after 2 attenuators X10 each)
Shown here are pixels (12,13)X(29,30)Slide13
Pulse height distribution 4x4
bkg
X axis – mV (this is after 2 attenuators X10 each)
Shown here are pixels (10,11)X(31,32)Slide14
Pulse height distribution 4x4
bkg
X axis – mV (this is after 2 attenuators X10 each)
Shown here are pixels (12,13)X(31,32)Slide15
Pulse height distribution 4 center pixel under source
X axis – mV (this is after 2 attenuators X10 each)
Shown here are pixels (12,13)X(31,32)Slide16
Bkg hit measurement on 4X4 array
We used the common trigger for counting the rate on the 16 pixels.60 consecutive measurements were made, each of 15 min (as before) total of 15hours.
Measurement started at Sat. Dec.3 at 6PMConnected pixels: RO lines: 10-13
HV lines: 29-32 As
before: 850VSlide17
Rate over time (16 pixels)
A few hours later, no pulses were seen at 850V at all.
When voltage was
raized to ~870 a fast rate was observed but coming only from one pixel (10X32)
The signal itself was different – lower &slower.
The beginning of the measurement shows the same behavior as the measurement of one pixel,
But,
Clearly something happened after ~7 hours Slide18
A few hours later and @870 VSlide19
Summery
Background needs to be further investigated, after a suck n’ bake we shall replace the current Gas with a new one (still Ar-CF4 at the same pressure and percents) and will try to repeat the hit rate over time experiment.
it seems that both the pulse height and rise time distributions are very narrow but a better examination is needed because of unexpected peaks.