Particle identification in STAR (status and future) R.Majka, N.Smirnov. Yale University (for the STAR experiment) 5 th International Workshop on Ring Imaging Cherenkov Detectors. Playa del Carmen, Mexico, Nov. 30 – Dec. 5, 2004. STAR Detector at RHIC, BNL was designed primarily for measurements of hadron production over a large solid angle, featuring detector systems for high precision tracking, momentum reconstruction and particle identification. The hadron identification was done using dE/dX data, and topological identification of decaying particles by secondary vertices finding and/or reconstructing invariant masses. The CERN-STAR RICH Detector extended the particle identification capabilities for charged hadrons at mid-rapidity. ToF Detector (MRPC technology) construction and installation is in a progress. First results are available and will be presented. The simulated performance of a fast, compact TPC in combination with a Cherenkov CsI Pad Detector for enhanced e+/- identification will be discussed as a possible variant of a STAR upgrade
24
Embed
Particle identification in STAR (status and future) R.Majka, N.Smirnov. Yale University (for the STAR experiment) 5 th International Workshop on Ring Imaging.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Particle identification in STAR(status and future)
R.Majka, N.Smirnov. Yale University
(for the STAR experiment)
5th International Workshop on Ring Imaging Cherenkov Detectors. Playa del Carmen, Mexico, Nov. 30 – Dec. 5, 2004.
STAR Detector at RHIC, BNL was designed primarily for measurements of hadron production over a large solid angle, featuring detector systems for high precision tracking, momentum reconstruction and particle identification. The hadron identification was done using dE/dX data, and topological identification of decaying particles by secondary vertices finding and/or reconstructing invariant masses.The CERN-STAR RICH Detector extended the particle identification capabilities for charged hadrons at mid-rapidity. ToF Detector (MRPC technology) construction and installation is in a progress. First results are available and will be presented. The simulated performance of a fast, compact TPC in combination with a Cherenkov CsI Pad Detector for enhanced e+/- identification will be discussed as a possible variant of a STAR upgrade
STAR DetectorSTAR Detector
2 m
2 m
B = 0.5 T
dE/dx at low pT
On-line TPC track reconstruction
Time Projection Chamber: 45 padrow, 2 meters (radius), dE/dx)8%, -1<
Hadron identification: STAR Collaboration, nucl-ex/0309012
ToF + dE/dX: “Hadron-Blind Detector”
Electron identification: TOFr |1/ß-1| < 0.03 TPC dE/dx electrons!!!
electrons
nucl-ex/0407006
carbon composite (75 m)Young’s modulus 3-4 times steel
aluminum kapton cable(100 m)
silicon chips(50 m)
21.6 mm
254 mm
Mechanical and Mechanical and integration issues are integration issues are being addressed:being addressed:
Existing SiliconExisting Silicon
Two Two Layers of Layers of APSAPS
Integration volume and rapid Integration volume and rapid insertion/removal being studied insertion/removal being studied using modern 3-D modeling using modern 3-D modeling tools.tools.
Features of First Generation Design:Features of First Generation Design:
• 2 layers2 layers
• Inner radius ~1.8 cmInner radius ~1.8 cm
• Active length 20 cmActive length 20 cm
• Readout speed 4 ms (generation 1) Readout speed 4 ms (generation 1)
• Number of pixels 130 M ( 20 x 20 Number of pixels 130 M ( 20 x 20 μμm² pixel size)m² pixel size)
STAR Upgrades R&D Proposal • The broad strategy for upgrading the STAR Detector includes: “Improve the high-rate tracking capability and develop the
technology for eventual replacement of the Time Projection Chamber.”
STAR tracking issues that need to be addressed and solved ( at upgraded RHIC luminosity )
• TPC Event pile up• TPC Space Charge• Additional tracking, PID Detectors• Trigger power improvement• Increase data rate
Possible solution. Future STAR tracking / PID set up (TPC replacement )
16 identical miniTPC’s with GEM readout; “working” gas: fast, low diffusion, UV transparent. dR = 20-50 cm, dZ=+/-45 cm, maximum drift time – 4.5 μs. with enhanced e+/- PID capability (Cherenkov Detector in the same gas volume)
3-4 layers of Pad Detectors on the basis of GEM technology: needed space resolution, low mass, not expensive, fast (∆t ~ 10 ns )
Allows consideration to use the space for more tracking
Fast, Compact TPC with enhanced electron ID capabilities
2 x 55. cm
16 identical modules with 35 pad-rows, double (triple) GEM readout with pad size: 0.2x1. cm². Maximum drift: 40-45 cm. “Working” gas: fast, low diffusion, good UV transparency .
STAR tracking, proposed variant
Pad Detector III
Pad Detector II
Pad Detector I
Beam Pipe andVertex Detectors
miniTPC
ToF
EMC
Magnet
y
x
R
z
HBD PID, step 1 (for “low” Pt tracks)
For all found in miniTPC tracks dE/dX analysis/ selection were done;
then some number of tangents to selected tracks were calculated and “crossing” points with Pad Det (if it was possible) were saved,
“search corridor” was prepared.
Pad Det with CsI (GEM ?!)
y
xZ, cm
φ, rad
HBD PID, step 2, (for “high” Pt e+/-)
• For tracks that crossed Pad Detector I, a matching procedure was done ( TPC track – Pad Det Hit ), and an analysis took place to check the number of UV-photons hits inside of cut values (which are the function of Pt, Pz)
e-
miniTPC hits
Pad Det I hits
Pad Detector response simulation, and e+/- PID
Central Au+Au event (dNch/dY~750), simulated using HIJING event generator with “full scale” detectors response simulation,Reconstructed hit positions, Z-Rphi, cm