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TAU - status TAU - status

TAU - status - PowerPoint Presentation

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TAU - status - PPT Presentation

September 7 Status We are on our way to better characterize the Panel background We see some strange behavior which might shad some light on the subject Sensitivity is being explored ID: 419797

time panel tau status panel time status tau 2011 report hodoscope amp rate background measurement decay minute people measurements

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Slide1

TAU - status

September 7Slide2

Status

We are on our way to better characterize the Panel background.

We see some “strange behavior” which might shad some light on the subjectSensitivity is being exploredWe see cosmic muons with VP1.An accurate apparatus to hold the hodoscope and the source above the panel is in final stages of preparationA complete voltage scan is still missing…

9/7/2011

2

TAU - status reportSlide3

Panel

Source

Hodoscope

COUNTER

Discriminator

Threshold = 500 mV

Discriminator

Threshold = 50 mV

OR

AND

AND

Hodoscope

16 pixels

Quench resistors: 20

Mohm

(per line)

4 RO lines: voltage divider (100:1 Ohm)

Every RO line into discriminator -> logic

Set-UpSlide4

Hit rates in the panel

Rate rises with voltage

Every entry in the histograms is a 5 minute counting experiment

9/7/2011

4

TAU - status reportSlide5

Coincident rate between the panel and the hodoscope

Does electron induced rate reach a plateau???

9/7/2011

5

TAU - status reportSlide6

Excess of panel hits

Bkg rate in the panel is ~

1 per minute

At 990 Volt we see: ~12 per minute in the panel~1.4 per minute trigger && panel

If only charged particles induce signals than:Bkg

+ Trigger&&panel = total panel rate

Where does the extra 10 hits per minute come from???

9/7/2011

6

TAU - status reportSlide7

Panel response to Xray

?

Instead of the hodoscope we placed a 3mm lead plate between source and panel

Background and X-ray response measurements were done separately the setup is slightly different so the exact rate values are meaningless…

Unrelated

measurements

9/7/2011

7

TAU - status reportSlide8

Rate decay – panel relaxation time after HV off time

HV

Time

Off time

Measurement

Measurement

Off

time = 1 hour

Off

time = 30 min

9/7/2011

8

TAU - status reportSlide9

Rate decay – panel relaxation time after HV off time

???

Off

time = 45 min

Off

time = 15 min

9/7/2011

9

TAU - status reportSlide10

Rate decay –

panel relaxation

time after

HV off time All measurements were done exactly in the same wayWe did not touch the system between the measurementsThe 45 minutes measurement was the last oneMaybe its important how long was the system running before the shut-down

9/7/2011

10

TAU - status reportSlide11

Muon detection

Large variations in background

needs

to be better monitoredTotal of: 12783 hodoscope triggers

5848 panel signals20 coincident signals (panel && hodoscope)

Panel active area ~16mm

2

Hodoscope active area ~2.5cm

2

Naive efficiency calculation:

Panel efficiency for muons ~2.5%

First 100 hours of measurement

9/7/2011

11

TAU - status reportSlide12

Beam test preparations

who is coming, minimal staff:

1 technician

2 physicists 1 electronics expertEquipment requirements:Vacuum pump & Gas systemGassesTrigger systemElectronic ROPanelsComputersTools

Physics study: all with two gasses and different panel areas

Detector check (background, HV scan and reproduce known results)Pulse shape study (scope/DRS4) Time arrival study

Rates and efficiencies

Tracking (two panels) – ambitious

Time

requirement

One week of physics (4 people)

5 days installation (2 people)

3

days unplug & packing (2 people)

9/7/2011

TAU - status report

12Cost estimations (no flight tickets – 4 people)

~9K$Slide13

conclusions

A monitoring system (Temperature, HV, pressure etc.) should be installed in our lab.

A long cosmic/background measurement is needed in order to reproduce the large variations in background rate

Temp and HV should be monitored during the measurementRate decay after some HV off time can mean:A characteristic of the panel which should always be taken into account in future experimentsA Temperature/HV related effect which was also manifested in the long cosmic measurementX-ray – we have a beam in TAU and we shall check their schedule and beam proparties

.

9/7/2011

13

TAU - status report