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Start Detector for TOF@CBM@FAIR observation simulation realisation. P.Koczo ń / DetLab GSI Helmholtzzentrum für Schwerionenforschung GmbH. Piotr Koczoń,GSI. ADAMAS Dec 2012. CBM@FAIR 2018?. Piotr Koczoń,GSI. ADAMAS Dec 2012. Compressed Baryonic Matter exp. Reaction products.
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Start Detector • for TOF@CBM@FAIR • observation • simulation • realisation P.Koczoń / DetLab GSI Helmholtzzentrum für Schwerionenforschung GmbH Piotr Koczoń,GSI ADAMAS Dec 2012
CBM@FAIR 2018? Piotr Koczoń,GSI ADAMAS Dec 2012
Compressed Baryonic Matter exp. Reaction products TOF Target MVD+STS TARGET Piotr Koczoń,GSI ADAMAS Dec 2012
OBSERVATION:backward hemisphere is full of reaction products outside of acceptance in acceptance R=30mm BEAM TARGET Beam pipe: 2.5° Yoke: 25° Piotr Koczoń,GSI ADAMAS Dec 2012
Simulations to investigate • time resolution of the first hit • suitable detector geometry • hit density • Details of the FAIR-Root simulations : • event generators: • FAIR–IonGunAu on Au (for δ-electrons) • Urqmd (2 – 10 AGeVAuAu, NiNiMB and Central events) • detector: two discs or a tube- like or sphere cutout (R=30 mm) • ALLWAYS with an opening allowing for 25 deg acceptance cone • - sensor material: Si (just because available as activ mat.) • target Au, Ni, C • - projectile Au, Ni, p Piotr Koczoń,GSI ADAMAS Dec 2012
Simulations: central events D = 0 fm peripheral events (MB) events with impact parameter D larger than 10 fm (selected from the mbias urqmd-files) y empty events 99% HI produce only delta electrons D = impact_parameter 10 fm urqmd.auau.2gev.mbias.0021.ftn14 UQMD version: 10035 1000 10002 output_file… transformation betas (NN,lab,pro) 0.0000000… impact_parameter_real/min/max(fm): 10.98 0.00 15.82… equation_of_state: 0 E_lab(GeV/u): 0.1271E+01 sqrt(s.. event# 1 random seed: 67008028 (fixed) op 0 0 0 0 1 * 0 0 0 0 0 0 0 0 0 0 op 0 0 0 0 0 0 1 0 1 0 0 0 0 2 1 op 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 x Piotr Koczoń,GSI ADAMAS Dec 2012
28 mm Ideal spherical detector BEAM Piotr Koczoń,GSI Piotr Koczoń,GSI ADAMAS Dec 2012
FIRST particle RMS=4ps curling δ’s 2AGeV Au @ Au δ + Urqmd 2AGeV Au on 0.25mm Au (centr+MBias) Detector can distinguish between central, min bias and empty events (δE<10keV, holds also for a ring, or 2 discs shape) δ’s MinBias Central Tot Eloss [keV] time [ps] 25° Φ[deg] ALL Θ [deg] time [ps] HOTTEST area opening circumference of 88 mm ADAMAS Dec 2012 Piotr Koczoń,GSI
Sphere cutout (crown) geometries 16fold 2rings Θ=25-90 deg 8fold 1ring Θ=25-60 deg 60fold 1ring Θ=25-35 deg 120fold 2rings Θ=25-45 deg 300fold 6rings Θ=25-65 deg 240fold 4rings Θ=25-55 deg Piotr Koczoń,GSI ADAMAS Dec 2012
Urqmd pC @ 30 GeV (central), 8-fold crown Detector can deliver start signal for TOF with RMS ~ 20ps and efficiency ~ 50 % Timing: 18ps Eff=50% Piotr Koczoń,GSI ADAMAS Dec 2012
Realisation (possible sensors): price time res. rate cap. rad hardefficiency a) MCP discs of R=30mm + 70ps ++ + HI? >90% HI? b) Si detectors R=30mm + + + - >90% c) Diamond det. -- <5ps ++ + >90%? d) RPC barrel/discs ? <40ps 20kHz cm2 ++ >90 % e) DIRC barrel -- 50ps? ? +/- >90%? (highly) segmented detectors!!! Piotr Koczoń,GSI ADAMAS Dec 2012
Conclusions: presented results let us hope that it is possible to construct a detector - which can be used as START for TOF@CBM (with time res. ~ 20 ps and 50% efficiency for p+C) - at the same time it would be a reaction detector for AuAu, NiNi (distinguishing central and min-bias react’s from empty events) - could be used as reaction tag (data flow reduction est. by factor 2 – 3!) Piotr Koczoń,GSI ADAMAS Dec 2012
Outlook: Having a segmented detector in the vicinity of the target it should be possible to measure the reaction plane as well (subject for further smulations) Thank You Piotr Koczoń,GSI ADAMAS Dec 2012
Piotr Koczoń,GSI ADAMAS Dec 2012
Piotr Koczoń,GSI ADAMAS Dec 2012
Hit density Φ[deg] Θ [deg] in the HOTTEST (red) area (in the cell of 5x10deg ->2.6x5.2 mm = 13.6 mm2 size) 800 hits out of 1500 events -> 3.9 MHz/1 mm2 @ 1x109 s-1 Au on Au Piotr Koczoń,GSI ADAMAS Dec 2012
Z[mm] X [mm] For completeness: 2 discs of R=30mm Φ[deg] Θ [deg] Piotr Koczoń,GSI ADAMAS Dec 2012
start detector properties • - size: R~30 mm • rate capability: several MHz / mm2 (worst case) • first particle arrival time: RMS=10 ps • having energy resolution of ~ 10 keV it can be • used for discrimination between empty events • (only delta electrons) and nuclear reactions • and • for centrality selection Piotr Koczoń,GSI ADAMAS Dec 2012