FOPITOF Upgrade

1
FOPI-TOF Upgrade

• A.Schüttauf GSI

2
Outline

• FOPIs TOF Upgrade
• RPC-Hardware
• RPC-Electronic
• RPC-Interface
• Test beam results
• Summary Outlook

3
FOPI TOF-Upgrade
Physics case K- flow to determine in-medium
potential Needs improved TOF in the lt 100 ps for
kaon identifica-tion up to 1 GeV/c
4
Why RPCs ?
For high granularities experiments price is an
issue. FOPI TOF Size 5 m2 Channels
5000 ?tlt100 ps ??lt0.5 cm
Central Au-Au collision at 1.45 AGeV has
60- particles in the acceptance of the proposed
RPC barrel This needs a granularity of 700 cells
(2500 strips)
5
Strip Anode RPCs
6
TOF Detector Layout
1 Super module (SM) 5 RPCs 16 strips/RPC
7
Double hit capability
During the test beam in May 2002 we encountered
a problem with enhanced hit multiplicities in
the RPC. This could later be attributed to
internal reflections inside the counter.
Solution Adapt your counter to 50 1 ?
We went thru a painful review of our counter
impedance.
K.Hildenbrand, V. Simion
8
Electronic Design
Old
TAC
9
Electronic Resolution
10
RPC-Electronic Interface
Flexible kapton cable 3 layer design in 250
?m 16 strips with 50 ? lines
M. Ciobanu, S. Häussler
11
Test Setup Oct. 2003
Beam Protons at 1.0 2.0 AGeV Rate 20-80
Hz/cm2 Gas C2F4H2/isobutane/SF6 85/5/10
Setup
12
Reflections
Counter reflections are below 1 Reflection at
the Lemo? MEC1 adapter will disappear with new
interface.
13
Voltage Scan 90 cm RPC
Slewing correction
14
Voltage Scan 20 cm RPC
Strips wise
15
Summary Outlook

• Reflections solved ! r lt 1
• Intrinsic electronic resolution ?I lt 30 ps
• Clock distribution is working !! ?CS lt 15 ps
• Time resolution per module DaL 11a (14) ?t lt 80
  ps DaS 6a (12) ?tlt 70 ps
• Efficiency per module DaL 11a (14) eff.
  95 DaS 6a (12) eff. 99
• Flex. cable possible for timing.

• Double hit resolution !!!
• Two counter matching.
• Flex cable anode sandwich.
• 90 cm 6 gaps 50 ?.
• Fishing rod ? glass fiber ?
• From 1.1 mm ? 0.5 mm glass.
• From 300 ?250 ?m gap.

GSI-Future Compressed Bayonic Matter
(CBM) European JRA FEE-ASIC Readout (TAC)
Highly segmented anode structures.
16
People
GSI-KPI M.Ciobanu K.Hildenbrand
M.Marquardt A.Schüttauf V.Simion A.Weinert Forme
r C.Finck A.Gobbi GSI-ELEX E.Badura H.Hardel K.K
och R.Schulze
HD-University E.Cordier N.Herrmann
IPNE, Bucharest M.Petrovici
17
Reflections I
May-June 2002 Test Beam
N.Herrmann
18
Reflections II
Talk
?-Setup Coincidence of plastic and RPC
19
Double hit capability
Solution Adapt your counter to 50 1 ?
K.Hildenbrand, V. Simion
20
Dark rate

• Takes 3 day under high voltage.
• Does not scale with border length
• but with the area.
• Low value 1 Hz/cm2.

90 cm counter
20 cm counter
21
TAC Principal
TALK
22
OLD Tac-Quilo-Quisa
C.Finck, A.Gobbi
TALK
GSI-ELEX R.Schulze,H.Hardel K.Koch,E.Badura
23
Cluster Timing
TALK
DaS 6a 12 strips 6 gaps 9.6 kV
Time resolution per strip
Cluster parameters
24
Slewing Correction
Uncorrected TOF spectra for all strips.
Determined walk correction Twalk 100 ps
Corrected and normalized TOF
TALK
25
Setup Oct. 2003
Trigger ? PM1 PM2 Efficiency ? PM1 PM2
PM3
Talk