TAU - status

August 17

Status

• Large panel (VP1) is working and producing fast clean signals.

• With 1, 2 or 4 HV channels signals look and behave exactly the same.

• First measurements of response to radiation – both electrons and muons.

• Small panel (BN01) was tested and found to hold vacuum, should be tested for signals tomorrow.

Our hodoscope

• Roughly 2.5 cm2 of active area.

• Overnight measurement of 13hours beneath the panel give 1509 cosmic triggers

• This corresponds to ~2muons per minute

Signal shape study (VP1) set-up

• Quench resistors: 20 Mohm (per line)• 4 RO lines: voltage divider (100:1 Ohm)• MDT gas (Ar-CO2 93%-7%) 600 Torr• RO lines connected to scope

100 Ohm

Ni – RO line

1 O

hm

For each RO line

1 HV line

2 HV line

4 HV line

Efficiency tests Set-up

Panel

Source

HodoscopeAND betw

een

the s

cintilla

tors

OR between

the RO lines

counter

counterAND

counter

•Quench resistors: 20 Mohm (per line)•4 RO lines: voltage divider (100:1 Ohm)•Every RO line into discriminator -> logic

First attempt – Voltage scan, MDT gas @600Torr

• More triggers as Voltage rises!!!

• -> BAD grounding

965 970 975 980 985 990 9950

100

200

300

400

500

600

700

800

900

Trigger & Panel (10 minutes)events

Volt

965 970 975 980 985 990 9950

2000400060008000

100001200014000160001800020000

Panel (10 minutes)events

Volt

965 970 975 980 985 990 9950

200

400

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1000

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1400

Trigger (10 minutes)events

Volt

Adjustments• Every ground in the system was

connected to the other grounds with a thick wire.

• Coincidents between panel & trigger almost stopped We raised the voltage without

improvement White discoloration of the active

pixels is visible. Gas was changed to the same gas

type and pressure. New working area in the panel. Hodoscope was raised closer to

the panel

Second attempt – Voltage scan, MDT gas @600Torr

• Trigger is constant regardless to panel Voltage

• Almost no coincident between trigger and signal

955 960 965 970 975 980 985 990 995 10000

0.5

1

1.5

2

2.5

Trigger & Panel (10 minutes)events

Volt

events

Volt

955 960 965 970 975 980 985 990 995 10000

5000

10000

15000

20000

25000

30000

35000

40000

Panel (10 minutes)events

Volt

events

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events

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events

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955 960 965 970 975 980 985 990 995 1000750

800

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1000

Trigger (10 minutes)events

Volt

events

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Background

• Without the source sitting on the panel there is almost no background.

• No coincident between signal and the trigger At all

984 986 988 990 992 994 996 998 1000 10020

0.5

1

1.5

2

2.5

3

3.5

BKG - Panel (10 minutes)events

Volt

events

Volt

events

Volt

events

Volt

0 200 400 600 800 1000 120010

15

20

25

BKG - Trigger (10 minutes)events

Volt

events

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events

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events

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Efficiency tests Set-up 2

Panel

Source

HodoscopeAND betw

een

the s

cintilla

tors

OR between

the RO lines

counter

counterAND

counter

•Quench resistors: 20 Mohm (per line)•4 RO lines: voltage divider (100:1 Ohm)•Every RO line into discriminator -> logic

• Rate of upper scintillation counter is ~15KHz

• Rate of trigger is ~25 • We believe that upper

scintillation pad is at it’s rate limit

Third attempt – Voltage scan, MDT gas @600Torr

978 980 982 984 986 988 990 992 994 99610

2010

4010

6010

8010

10010

12010

14010

16010

Trigger (10 minutes)events

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events

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events

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events

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events

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events

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events

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events

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978 980 982 984 986 988 990 992 994 9961060

110160210260310360410460510

Trigger & panel (10 minutes)events

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events

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events

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events

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events

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events

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events

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events

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978 980 982 984 986 988 990 992 994 99610

210

410

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1210

1410

panel (10 minutes)events

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events

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events

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Plans for next week

• Signal shape studies with BN01 panel

• Rates study - continue with PV1, start with BN01 panel

• Expand the study to CF4