Proposed detector and data readout system
for the
India-based Neutrino Observatory(INO)
B.Satyanarayana
(For INO collaboration)
Department of High Energy Physics
Tata Institute of Fundamental Research
Homi Bhabha Road, Colaba, Mumbai, 400 005
E-mail: bsn@tifr.res.in
Plan of the talk
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Introduction
Proposed detector
RPC basics
RPC test stand
Gas mixing and distribution system
RPC R & D results
Electronics for the prototype detector;
Thoughts for the final detector
Status and future plan
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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What and Why Neutrinos?
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Neutrinos are one of the fundamental particles of matter.
Electrically neutral and were initially thought to be mass-less.
Three types or flavors of neutrinos known.
Recent evidence indicates that neutrinos have mass and also
experience mixing among these flavors.
Neutrino oscillations can explain the discrepancy between theory
and observations about its flux.
Neutrino mass can also be indirectly estimated by detecting its
eventual oscillations.
Non-zero mass for neutrino has profound implications on fields as
varied as nuclear physics, particle physics, astrophysics and
cosmology.
Pioneering experiments at the KGF underground laboratories
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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INO Collaboration
B.S.Acharya, Sudeshna Banerjee, P.N.Bhat, S.R.Dugad, P.Ghosh, K.S.Gothe, S.K.Gupta, S.D.Kalmani, N. Krishnan, N. K Mondal, B.K.Nagesh ,
P.Nagaraj, Biswajit Paul, A.K.Ray, Probir Roy, B.Satyanarayana, S.Upadhaya, P.Verma
Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai
V.M.Datar, M.S.Bhatia, S.K.Kataria
Bhabha Atomic Research Centre, Mumbai
P. Bhattacharya, S.Bhattacharya, S. Chattopadhyay, A.Ghoshal, A.Goswami K. Kar, D.Majumdar, P.B.Pal, S. Saha, M. Sharan, S.Sarkar, S.Sen
Saha Institute of Nuclear Physics, Kolkata
S. Chattopadhyay, M.R.Datta Mazumdar, P.Ghosh, G.S.N.Murthy, T.Nayak, Y.P.Viyogi
Variable Energy Cyclotron Centre, Kolkata
Amitava Raychaudhuri
Calcutta University, Kolkata
M.V.N.Murthy, D.Indumathi
Institute of Mathematical Sciences, Chennai
A. Datta, R.Gandhi, S.Goswami, S. Rakshit, P.Mehta
Harish Chandra Research Institute, Allahabad
S.C.Phatak, D.P.Mahapatra
IOP, Bhubaneswar
41 Experimentalists & Engineers
Amit Roy
22 Theorists
Nuclear Science Centre, New Delhi
J.B.Singh, M.M.Gupta, V.Bhatnagar
Panjab University, Chandigarh
S.D.Sharma
Himachal Pradesh University, Simla
A.Joshipura, S.Rindani
P.R.L., Ahmedabad
A.Bhadra,B.Ghosh,A.Mukherjee,S.K.Sarkar
North Bengal University
S.Umasankar
IIT, Mumbai
S.K.Singh
AMU
B.Satyanarayana,
Kalpakkam, February 17-20,
2004Amit Roy
Scientific
Advisors: TIFR, Mumbai
G.Rajasekaran, Bikash Sinha,NSNI-2004,
Ramnath Cowsik,V.S.Narasimham,
H.S.Mani,
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Proposed INO detector
Magnetised iron
calorimeter
• RPC dimension: 3m X 2m
• No of chambers: 11K
• No of channels: 220K
RPC
Iron
140 layers
• No of TDC channels: 3K
35KTons
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC principle of operation
Signal pickup(X)

Graphite
Glass
Plates
Signal pickup(Y)
Spacer
Graphite
A passing charged particle induces an avalanche, which develops into
a
2
spark. The discharge is quenched when all of the locally r(  0.1 cm )
available charge is consumed.
Before spark
++++++++++++++++++++
-------------------------
After spark
++++++
----------
++++++
-------
The discharged area recharges slowly through the high-resistivity glass
plates.
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC rate capability
Each discharge locally deadens the RPC.
The recovery time is approximately
+++++++
------------
+++++++
--------
  l    A 
  RC  
   

 A  l 
Numerically this is (MKS units)
 ( x 101 0 ) x 4 x (8.85 x 10-1 2 )  2 s
0.1 cm 2
2 discharge deadens an area of
Assuming
each
, rates of
500 Hz/m
upto
can be handled with 1% deadtime or less.
This is well below what is expected in our application.
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC construction
Two 2 mm thick float Glass
Separated by 2 mm spacer
Signal
pickup strips
2 mm thick spacer
Glass plates
Graphite coating on the outer surfaces of glass
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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A small area RPC prototype
Gas
inlet
Graphite
coat
Spacer
Gas
outlet
HV terminals
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Cosmic muon trigger and timing

P1
B.Satyanarayana, TIFR, Mumbai
P2
P3
P5
Muon Trigger =
Glass RPC under test
P4
P6
P1  P2  P3  P4  P5  P6
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC test setup
Cosmic muon
telescope
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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NIM and CAMAC electronics
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Telescope rate monitoring
280000
Telescope paddel rates
260000
240000
220000
P1
P2
200000
P3
180000
P4
160000
140000
120000
100000
1
2
3
4
5
6
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9
10
11
12
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14
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Time, Hours
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Schematic of gas mixing unit
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Gas mixing unit
Argon
Iso-butane
R134A(Freon)
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Schematic of digital gas bubble counter
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Digital gas bubble counter
Temperature
and RH meter
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical RPC pulse profiles
Trigger pulse
X-Strip
In streamer mode of operation,
pulses are large (>100 mV into
50) and fast (tr < 1ns)
Y-Strip
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical RPC efficiency plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical timing distribution plots
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical time response plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical time resolution plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC typical charge distributions
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC typical mean charge plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC pulse height Vs timing plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC typical noise rate plot
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Typical cross-talk plots
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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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
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Gas mixtures’ study plots
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Effect of water vapour in gas
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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Effect of water vapour in gas
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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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.
• Detail studies underway.
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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RPC recovery plots
No of hours of gas flow
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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New RPC test setup
8020
Sections
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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INO prototype detector
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Detector and signal specifications
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Trigger information
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Expected trigger rate is few Hz
Required Trigger logic is m X n fold, where
m = 1 to 4; no. of consecutive channels in a layer
n = 5 to 1; no. of consecutive layers with m fold in each layer
ie m x n = (1 x 5) OR (2 x 4) OR (3 x 3) OR (4 x 2)
Information to be recorded on a trigger
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Detector dimensions: 1m X 1m X 1m
14 layers of RPCs with 6cm iron plates interleaved.
Two signal planes orthogonal to each other and each having 32 pick-up strips
Total channels = 32 X 14 X 2 = 896
Pulse height = 100 to 300mV; Rise time = < 1 ns
Pulse width = ~50ns; Rate ~ 1KHz
Absolute arrival time of the trigger
Track identification (XYZ points in RPC layers)
Direction of track ( TDC information)
Miscellaneous information and calibration data
Monitoring health of the detector
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
35
Readout scheme for prototype
X-plane
Y-plane
Front End
Electronics
Y
X
1
CAMAC
RTC
Final
Trigger
TDC
2
1
Event Scalers
2
FEE
8
9
Control Logic
Read Data &
Monitor
Monitor
Scalers
8
9
10
10
14
CAMAC
Controller
14
Trig & TDC
Router
LAN
B.Satyanarayana, TIFR, Mumbai
PC
(LINUX)
NSNI-2004, Kalpakkam, February 17-20, 2004
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32-channel front-end module
1 2 3 ……………………………………………………………32
Trigger 0
Logic (ECL)
&
Trigger 1
M fold Logic
( CPLD )
LVDS
32 ECL Comparators
Threshold
Timing signal
Level Translator & Wave shaper (32+8)
Mon SI
EVE (SW4)
Board ID (SW8)
Monitor
MUX unit
( 40 : 1 )
MON(SW4)
Mon SO
Addr & Control
Module
Selection
Counter
Event Trig
SHIFT REGISTER ( 48 bit )
Eve SI
Eve SO
FPGA
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
37
Prototype detector trigger logic
Front End Electronics
Level-0
X-Plane
Y-Plane
S1=1+9+17+25
S2=2+10+18+26
……….
S8=8+16+24+32
S1….S8
Level 1
S1…S8
L14P1
(mF)
L1P1
(mF)
S1…S8
L14P2
(mF)
L1P2
(mF)
1F,2F……4F
1F,2F……4F
(LVDS interface)
1F,2F……4F
Trigger & TDC signals
Router
1F,2F……4F
Trigger & TDC signals
Router
Level-2 ( Back end )
F1(14)…………..F4(14)
F1(14)…………..F4(14)
(
P1
(m x n fold)
P2
(m x n fold)
OR
Final Trigger
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
38
Readout scheme for final detector
The keywords are channel count and fast timing
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
39
Current status and future plan
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Production and study of small area RPCs successful
Detailed study of effect of water vapour in gas
Repeatability of results and long term stability of RPC
Study of pickup strip materials and geometries
Production of prototype chambers (4 ft X 3 ft)
Gas mixing and distribution system for the prototype detector
Prototype electronics finalised
Production of circuit boards and other components in progress
Initial thoughts given on final electronics and DAQ schemes
Cooperative VLSI and ASIC development programmes explored
B.Satyanarayana, TIFR, Mumbai
NSNI-2004, Kalpakkam, February 17-20, 2004
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