rpc upgrade for the hades tracking: mdc e -,e + identification with rich- tof/preshower 0.4 gev/c...
TRANSCRIPT
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RPC RPC upgradeupgrade for the HADES for the HADES
Tracking: MDC
e-,e+ identification with RICH- TOF/PreShower
<450 and p>0.4 GeV/c TOF is not sufficient- Pre-Shower
p, identification TOF-Tracking
RICH
MDC I/II
coils
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HADES’2003 TOF walls
Outer TOF wall >450:
6 * 64 scintilator rods. TOF & position measurement
t : 120 ps , x2cm dE/dx measurement
TOFINO
Pre-Shower
target
Inner TOF wall <450:
6 * 4 scintilator paddles TOF measurement
t : 550 ps, no x dE/dx measurement
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p [MeV/c]
Fra
ctio
n o
f id
enti
fied
π+
π+
pfakefake π+
other
Inner Inner TOF performanceTOF performance in in C+C@2AGeVC+C@2AGeV
TOF [ns] TOF [ns]
Hadron id Lepton id
q*p
[M
eV
/c]
RICH
Pre-Shower
Pion id
double elec. hits
• no e/ separation by TOF : only with RICH+PreShower: e+ for p<0.4 GeV/c )
• TOF measurement limited to light systems (C+C)-double hits!
• no spatial resolution (pair analysis!)
• /p separation for p< 1 GeV/c
• no K/ separation
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Resistive Plate Counters for HADESResistive Plate Counters for HADES
Requirements for an RPC TOF detector for HADES:
-Adequate granularity (HI collisions)- double hit probability<10%
6 sectors: 660 counters with 4 gaps (99% efficiency)
-Time resolution below 100 ps :
e/ separation for p<0.4 GeV/c (95% CL)
/p separation
/K separation for p<1.GeV/c (99% CL)
-Space resolution around S=3 cm2
electron pair analysis.
-Stable behaviour at rates of few hundreds of Hz/cm2 and in presence of high ionising particles
high resistive glass (2.5mm thick)
Negligible cross talk
Isolated detector modules
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Physics cases for new TOFPhysics cases for new TOF• High intenisty pion beams:
o continuation of HADES pion programme : dielectron production in -p (proposal S262): -pe+e-n, -pR / n (/ coupling to S11(1535),
D13(1520))
Beam intenisty I- = 4*106/spill(4s)
to exclusive +p reactions: +pR / p +
@1.3 GeV/c „subthreshold omega”- „deflation” D37(1930),F37(1930)
@ 2.35 GeV/c electromagnetic 0e+e- form-factor (VDM „puzzle”)
Beam intenisty I+ =5.2*106/spill (4s) @1.3 GeV/c, 3.6*106/[email protected] GeV/c
p/ separation at high momentum
o @ 1.3 GeV/c Recoiless production in - Pb collisions (in-medium effects)
o Weak-electromagnetic structure of hyperons
+ pK++ K+ Xe+e- (1.8 GeV/c) Kaon tagging ! Increase of pion beam intensity
physics. OZI rule violation in pion and proton induced reactions.
identification via kaon decays
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Physics cases with new TOFPhysics cases with new TOF
• HI collisions above C+C @1-2 AGeV
• HI collisions at new SIS facility C+C @ 8AGeV
• same detector geometry
• Similar LVL1 rate
• Slightly higher p/+ momenta in forward TOF
• 15k /5 day run
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RPC geometryRPC geometry
Top view of one sector
• electron identification > 0.9 even for 1 AGeV Au+Au
• Rate < 700 Hz/cm2 for Au+Au 108 ions/spill
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RPC prototype performance @2AGeV RPC prototype performance @2AGeV C+CC+C
Gas admixture: 98.5% C2H2F4 + 1% SF6 + 0.5 isoC4H10
160cm long
4 gaps
0.3cm gap
Cross talk < 0.4%
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RPC read-outRPC read-out
Front-end on detector (preamp, shaper,discriminator) – commercial components-tested in beam
2 time read-out/ module (1320 TDC channels)
1 charge /module (660 ADC or Time over Threshold)
CAEN 132 channel multi-hit TDC („plug and play”)
F1-TDC multi-hit digital TDC + fast internet controler (development)
GSI TAQUILA (development)
Proposals in evaluation by HADES DAQ (decision about prototypes in February 2003)
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Project organisation and cost Project organisation and cost estimateestimate
• Detector construction: LIP Coimbra, Univ. Santiago, INR Moscow
• Front-end :Univ. Santiago, CIEMAT-Madrid
• Digitial read-out and DAQ: GSI, Univ. Giessen, Univ. Cracow
1 sector prototype scheduled on autumn 2004
Detector mat. 100 k€
Machining 80 K€ 180 k€ Det.mechanics 30 k€
LV,HV 35 k€
Gas system 15k€ 80 k€ Front-end 60 k€
Digitizers+DAQ 120 k€ 180 k€ 440 k€ + 2Phd positions
Investment: