Transcript Slide 1

CBM – Russia meeting at ITEP, Nov 5th, 2004
ITEP participation
to the CBM TOF project
ITEP ALICE - TOF group
ITEP background in gaseous TOF technology
ITEP
Moscow
Long-Term R&D Experience
on Avalanche Gaseous Detectors
for TOF Applications
since 1990
1991 - ITEP Proposal for HI
Proto Collab. – then ALICE:
to develop new technology of
avalanche gaseous detectors
with planar electrodes for high
precision large area TOF
ITEP – since 1991 – key participant of the ALICE PID/TOF project based on this
technology : initially PPC, then RPC (DRPC, GRPC) – for sparks suppression,
for construction – MRPC - all in the avalanche mode
ITEP - key participant in the discovery of new TOF technology
~ 50 psec resolution for MIP in ‘98
ITEP now – deeply involved in the ALICE TOF construction :
- technology of the TOF strips assembly
- different types of the equipment/tooling needed for the assembly
- TOF strips and modules tests with beam and cosmic
- ALICE TOF Cosmic Test Facility at CERN
( in part. muon trigger system)
ALICE TOF Tooling
Test assembly of a TOF strip
involving new ITEP equipment
ITEP
A new ITEP device for vacuum handling
of a 1.2 m-long TOF strip elements
(containing PCBs and thin glass plates)
ITEP specialists have just positioned
a thin glass plate on a PCB surface
by means of the vacuum handler
ALICE TOF Tooling
Test assembly of a TOF strip
involving new ITEP equipment
ITEP
TOF group members, discussing the
technology of the TOF strips assembly
A device for film gluing
and a special table for precision
fixation of the strip elements
ALICE TOF Tooling
ITEP
A-A
ITEP technicians,
working on the
technology of the
TOF strips assembly
A
A
Different types of devices to
be used in uniform covering
of the TOF strip glass plates
with insulating films
ИТЭФ
Close ITEP plans on the CBM TOF
: simulations & RD
2004 - newcomer
a)
Optimization of the structure of TOF
systems
b) Influence of the time resolution to
physics
Simulations of TOF performance
c)
Tests of RPC with the Russian lowresistivity glass at ITEP PS
d) PID performance
Data analysis
a)
Efficiency, matching, contamination
Tests of glass RPC in laboratory and
by beam
b) Optimization of the detector design
2005
c)
Optimization of FEE, other electronics
More simulations of TOF performance
Enhanced TOF contribution to
physics
Further R&D on TOF by RPC
More R&D
Surface resistivity instead of volume
- for instance - ITEP DRPC
(Dielectric – Resistive Plate Chamber)
TOF occupancy
•
•
•
•
•
1325 tracks cross TOF:
433(33%) primaries 892(67%)
secondaries
Composition of secon.: 62% e±,
16% p, 13% π±, 9% µ±
Origin of secondaries: 4% from
ECAL range, 37% - TOF, 12% TRD3, 9% - TRD2, 7% - TRD1,
6% -vertex
Max. occupancy: ~0.45 prim.
tracks, ~0.65 secon. tracks per
dm**2 at beam pipe
With 10 cm**2 cell size max.
occupancy ~ 11%
02.06.2004
ee+
p
± π±
TOF
TRD1
ITEP meeting
TRD2 TRD3
S.Kiselev ITEP
ECAL
10
TOF occupancy
02.06.2004
ITEP meeting
S.Kiselev ITEP
12
TOF RPC at the ALICE conditions
TOF efficiency v.s. electric field.
TOF resolution v.s. electric field.
120
100
110
95
100
September test
 TOF , ps
TOF , %
90
85
September test
80
200m 6 gaps
230m 6 gaps
260 m 6 gaps
310m 6 gaps
310m 4 gaps
75
70
200m 6 gaps
230m 6 gaps
260 m 6 gaps
310m 6 gaps
310m 4 gaps
90
80
70
60
50
65
40
7.5
8.0
8.5
9.0
9.5
10.0
E , kV/mm
10.5
11.0
11.5
12.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
E , kV/mm
Glass resistance R 1013-12 Om cm, rate limit - less 1kHz/cm2
11.0
11.5
12.0
CBM TOF
~ up to 150 m**2,
up to 150 K Chan.
RPC TOF rate capability
ALICE
-
CBM -
50-100 Hz/cm**2
up to 50 kHZ/cm**2 !
x 1000 times !
HADES test
normal glass
~ 10**12 Om cm
High-Rate Low-Resistive-Glass RPC for
TOF Measurements
A. Akindinov ITEP (Moscow) for collaboration:
IHEP (Protvino) – INR (Moscow) – ITEP (Moscow)
CBM Collaboration Meeting
October 6-8, 2004, GSI Darmstadt
Glass Resistivity
10
10
Glass by INR
• phosphate
• low-resistive
9
10
0
0.2
0.4
0.6
0.8
1
U, kV
• electron type of conductivity
as a function of high voltage
• produced in Moscow
• plates thickness – 2 mm
• plates : cut and polished
U = 1 kV
10
10
9
10
02
468
10
Time, h
as a function of time
RPC by IHEP
lemo type
connector
HV
• gaps – 4  0.3 mm
• plate size – 50  55 mm2
• readout pad – 40  40 mm2
• HARP type
• spacers – fishing lines Ø 0.3 mm
signal pad
2mm glass
graphite
maylar
box
spacer
• tight aluminum gas box
Beam tests
•10 GeV ITEP proton synchrotron
• protons, p = 1.7 GeV/c
• up to 0.5106 particles/spill
• spill duration – 300 ms
• beam spot – 5  5
cm2
• trigger – 6-fold coincidence of
scintillator counters + MWPC
tracking
• two TOF systems (5m base and
13 m base)+ Cherenkov detector
Gas supply
85% tetrafluorethane
10% SF6
5% i-C4H10
5 l/h
gas box volume – 1 l
Front-End Electronics
• single-channel card with
discrete surface mounted
elements
• put outside the gas box
• based on MAX3760 amplifier
• gain – 2.5 V/pC
• rise-time – 1.4 ns
Beam test facility
• start system timing resolution
– 70 ps (50 ps for start signal)
• trigger size at the RPC plane
– 1.2  1.2 cm2
• studied occupancies – 2.25,
4.5, 9.0, 18.0 kHz/cm2
• statistics – 105 events/point
• linearity – up to 100 fC
• noise – 1200 e- + 300 e-/pF at
the input
• threshold – 10 fC
• σnoise < 20 ps
Data acquisition and analysis
TDC LeCroy 2228
ADC LeCroy 2249
offline analysis with polynomial T-A correction
Beam tests at ITEP PS (June 2004)
100
200
180
98
160
96
140
120
94
100
● — TOF resolution
80
60
92
■ — efficiency
02468
10
12
14
2
Occupancy, kHz/cm
16
18
20
90
TOF resolution
σ = 99 ps
Occupancy — 2.25 kHz/cm2
σ = 112 ps
Occupancy — 9 kHz/cm2
σ = 106 ps
Occupancy — 4.5 kHz/cm2
σ = 125 ps
Occupancy — 18 kHz/cm2
Main RD direction:
to build functional detector with a glass with
enough low resistivity.!
Bulk or Volume resistivity
Special low resistivity glass:
well known problem since RD on Pestov
Another way – surface resistivity
Example :
- DRPC invented by ITEP in 1998
DRPC (Dielectric-Resistive Plate Chamber)
In reality – the very first example of novel TOF
technology:
~ 80 psec in 1998
Patent of Russia :
№ 2148283, 1998
Preprints ITEP 45-98, 1998
20-99, 1999
46-00, 2000
13-02, 2002
NIM A494, pp 474-479, 2002
ITEP DRPC
as a very high rate
TOF detector . ?
4 x 0.3 mm gaps
ceramic + SiC electr.