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Charged Particle Tracker for a RHIC/EIC joint detector. Detector layouts based on EIC and NLC Physics drivers Silicon detector technologies Simulations based on different layouts. Rene Bellwied, Wayne State University RHIC/EIC joint detector discussion, BNL, Sept.19th.
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Charged Particle Tracker fora RHIC/EIC joint detector • Detector layouts based on EIC and NLC • Physics drivers • Silicon detector technologies • Simulations based on different layouts Rene Bellwied, Wayne State University RHIC/EIC joint detector discussion, BNL, Sept.19th
The EIC parton detector concept Magnetic field strength: ?
For comparison: two LC detector options Old B = 5 T B = 3 T Both detector options have now all calorimetry inside the magnet.
Silicon detector option for LCD(small detector, high field B=5T) Forward tracker: Silicon Strip Five disks uniformly spaced in z Radiation length / layer = 1.0 % Double-sided with 90 degree stereo, sigma = 7mm Inner radii Outer radii Z position ----------- ----------- ---------- 4.0 cm 20.50 cm 27.1 cm 7.9 cm 46.75 cm 62.1 cm 11.7 cm 73.00 cm 97.1 cm 15.6 cm 99.25 cm 132.1 cm 19.5 cm 125.50 cm 167.1 cm Vertex detector:CCD 5 layers uniformly spaced (r = 1.2 cm to 6.0 cm) Half-length of layer 1 = 2.5 cm Half-length of layers 2-5 = 12.5 cm sigma_rphi = sigma_rz = 5 microns Radiation length / layer = 0.1 % Central tracker: Silicon Drift DetectorsFive layers Radiation length / layer = 0.5 % sigma_rphi = 7 mm, sigma_rz = 10 mm Layer Radii Half-lengths ----------- ------------ 20.00 cm 26.67 cm 46.25 cm 61.67 cm 72.50 cm 96.67 cm 98.75 cm 131.67 cm 125.00 cm 166.67 cm 56 m2 Silicon Wafer size: 10 by 10 cm # of Wafers: 6000 (incl. spares) # of Channels: 4,404,480 channels (260 mm pitch)
The SCT Semiconductor Tracker Barrel diameters: B3: 568 mm B4: 710 mm B5: 854 mm B6: 996 mm 4088 Modules ~ 61 m2 of silicon 15,392 silicon wafers ~ 6.3 million of readout channels 5.6 m 1.04 m 1.53 m 9 wheels 4 barrels 9 wheels
CMS Silicon Detector 9,648,128 strips = electronics channel 440 m2 of Si wafers, 210 m2 of Si sensors
Stripixels:something new from BNL(why ? SDD’s might be too slow) Alternating Stripixel Detector (ASD) Interleaved Stripixel Detector (ISD) Pseudo-3d readout with speed and resolution comparable to double-side strip detector (Zheng Li, BNL report, Nov.2000)
The SVT in STAR The final device…. … and all its connections
STAR-SVT characteristics • 216 wafers (bi-directional drift) = 432 hybrids • 3 barrels, r = 5, 10, 15 cm, 103,680 channels, 13,271,040 pixels • 6 by 6 cm active area = max. 3 cm drift, 3 mm (inactive) guard area • max. HV = 1500 V, max. drift time = 5 ms, (TPC drift time = 50 ms) • anode pitch = 250 mm, cathode pitch = 150 mm • SVT cost: $7M for 0.7m2 of silicon • Radiation length: 1.4% per layer • 0.3% silicon, 0.5% FEE (Front End Electronics), • 0.6% cooling and support. Beryllium support structure. • FEE placed beside wafers. Water cooling.
Wafers: B and T dependence • Used at B=6T. B fields parallel to drift increase the resistance and slow the drift velocity. • The detectors work well up to 50oC but are also very T-dependent. T-variations of 0.10C cause a 10% drift velocity variation • Detectors are operated at room temperature in STAR. • We monitor these effect via MOS charge injectors
Present status of technology STAR • 4in. NTD material, 3 kWcm, 280 mm thick, 6.3 by 6.3 cm area • 250 mm readout pitch, 61,440 pixels per detector • SINTEF produced 250 good wafers (70% yield) ALICE • 6in. NTD material, 2 kWcm, 280 mm thick, 280 mm pitch • CANBERRA produced around 100 prototypes, good yield Future • 6in. NTD, 150 micron thick, any pitch between 200-400 mm • 10 by 10 cm wafer
Mature technology. <10 micron resolution achievable with $’s and R&D. Easy along one axis (anodes). <0.5% radiation length/layer achievable if FEE moved to edges. Low number of channels translates to low cost silicon detectors with good resolution. Detector could be operated with air cooling at room temperature Silicon Drift Detector Features
Tracking efficiencies LD vs. SD • Tracking efficiencies: • For 100% hit efficiency: (95.3±0.13)% • For 98% hit efficiency: (94.5±0.14)% • For 90% hit efficiency: (89.5±0.20)% • LD SD Tracking efficiencies: • For 100% hit efficiency: (97.3±0.10)% • For 98% hit efficiency: (96.6±0.12)% • For 90% hit efficiency: (92.7±0.16)%
Missing and ghost energies • For hit efficiency 100%: • Missing energy = (11.7±0.6) GeV = (7.1±0.3)% • Ghost energy = (19.6±0.8) GeV • = (13.1±0.6)% • LD SD For hit efficiency 100%: • Missing energy = (5.7±0.4) GeV = (3.3±0.2)% • Ghost energy = (4.8±0.4) GeV = (2.9±0.2)%
With the maximum of d3p distribution at ~(1.5-2)10-3, the data are consistent with the earlier momentum resolution simulations (B. Schumm, VR, et al): within a factor of ~2 in the momentum range of 0.5 GeV/c < pT < 20 GeV/c. Preliminary conclusions • Momentum resolution • With the existing 3d tracking and pattern recognition software (Mike Ronan et al.) the Silicon option has a slight advantage in tracking efficiency, shows less missing and ghost energy, and less ghost tracks)
Improve position resolution to 5mm Decrease anode pitch from 250 to 100mm. Stiffen resistor chain and drift faster. Improve radiation length Reduce wafer thickness from 300mm to 150mm Move FEE to edges or change from hybrid to SVX Air cooling vs. water cooling Use 6in instead of 4in Silicon wafers to reduce #channels. More extensive radiation damage studies. Detectors/FEE can withstand around 100 krad (g,n) PASA is BIPOLAR (intrinsically rad. hard.) SCA can be produced in rad. hard process. R&D for Large Tracker Application
The CLEO calorimeter Calorimeter specs: 7,800 Th doped CsI crystals (6,144 in barrel) Each crystal 5 by 5 by 30 cm Angular Resolution ~5-10 mrad Barrel resolution: sE/E (%) = 0.35/E0.75 + 1.9 - 0.1E Endcap resolution: sE/E (%) = 0.26/E + 2.5 = 2-3% for 1 GeV e- or g CLEO II quadrant view