The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 1

Development of RPCs for INO

B.Satyanarayana

TIFR, Mumbai, INDIAbsn@tifr.res.in

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 2

A passing charged particle induces an avalanche, which develops into a spark. The discharge is quenched when all of the locally ( ) available charge is consumed.

2cm 1.0r

The discharged area recharges slowly through the high-resistivity glass plates.

Before spark After spark

Signal pickup(X)

Signal pickup(Y)

GlassPlates

Graphite

Graphite

Spacer

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Principle of operation

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 3

RPC test setup

Telescope

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 4

P1P2

P3

P4P5

P6

RPC under test

Muon Trigger =654321 PPPPPP

Cosmic muon trigger and timing

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 5

NIM and CAMAC electronics

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 6

Telescope rate monitoring

215000

225000235000

245000

255000265000

275000

1 4 7 10 13 16 19 22 25 28 31 34 37 40

Time, Hours

Padd

le ra

tes

120000

125000

130000

135000

140000

145000

150000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Time, Hours

Padd

le ra

tes

32000

33000

34000

35000

36000

37000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39

Time, Hours

Pad

dle

rate

s

150

200

250

300

350

400

1 4 7 10 13 16 19 22 25 28 31 34 37 40

Time, Hours

Trig

ger r

ates

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 7

Gas mixing unit

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 8

Typical efficiency plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 9

Studies with gas mixtures

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 10

Typical timing distribution plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 11

Typical time response plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 12

Typical time resolution plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 13

Typical charge distribution plots

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 14

Typical mean charge plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 15

Typical noise rate plot

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 16

Typical cross-talk plots

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 17

Summary of cross-talk measurements

Gas Mixture Slit Size(mm) Cross talk(%)

62:8:30 10 6.8

62:8:30 15 6.7

62:8:30 20 6.2

57:8:35 20 6.5

52:8:40 20 5.9

46:8:46 20 6.3

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 18

Effects of wet gases

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 19

Recovering a damaged RPC

• Purging with pure Argon at high flow rate.• Bubbling pure Argon through pure ethyl

alcohol.• Bubbling pure Argon through 25% Ammonia

solution for 24 hours without electric field.• Recovers efficiency and brings down noise rate.• Detailed studies underway.

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 20

RPC recovery plots

No of hours of gas flow

The 6th ACFA Workshop on Physics and Detector at Linear Collider, TIFR, Mumbai, December 15-17, 2003 21

Future plans

• Study of effect of wet gases on RPC performance, aging etc.

• Study of pickup strip materials, geometries & pulse characteristics

• Long term studies with small chambers.• Improvements in the gas mixing unit, Cosmic test

setup, etc.• Procurement of dry gases.• Production of 120cm X 90cm RPCs for prototype

detector