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VTX. PHENIX Central Region. From VTX Proposal (dims in mm). HBD is standalone. VTX Barrel Geometry. 14 cm. 2.5 cm. GEANT by VR. VTX Barrel Specs. Not updated in proposal. VTX Endcap Geometry. How VTX fits. Lots of comments about this. VTX layout changed, but envelope remains the same.
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PHENIX Central Region From VTX Proposal (dims in mm) HBD is standalone
VTX Barrel Geometry 14 cm 2.5 cm GEANT by VR
VTX Barrel Specs Not updated in proposal
How VTX fits Lots of comments about this VTX layout changed, but envelope remains the same
h = 0.35 h = 0.70 h = 0.88 Planar GEM tracking chambers h = 1.17 h = 2.6 Provides tracking coverage over -2.6 < h < 2.6 Space for the TPC is being squeezed by the need to bring out services for the VTX and the need for space for the readout electronics From: C. Woody 10-15 cm
Mylar Sleeve • Proper grounding & isolation of Si detector • Image charge from circulating beam • Aluminized Mylar sleeve around Be beam pipe • Few mm’s thick to hold down material budget • Grounded w/ braid through magnet • No interference with other sub-systems; nothing else between beam pipe and 1st pixel layer • General agreement this is OK
VTX Mechanical Support Structure • Frame for barrel & end caps (HYTEC and LANL) • External support structure in central magnet (BNL) • Mechanical tolerances/distortions: • < 25 mm internally • ~4x this amount relative to the rest of the detector • From CAD Survey Group (F. Karl): • 50 – 100 mm on the bench • 100 – 200 mm in the hall
VTX Mech Support Structure (cont) • Modular design is necessary: • Easily removable from IR • Barrel and end caps mount separately • Mounted off of pole tips/nose cone calorimeter • To maintain specified tolerances • Alternate scheme proposed at Vanderbilt Meeting
Alternate Mounting Scheme From: van Hecke TPC mounts from top CM yoke. VTX Si detector comes in from bottom, much like MVD does now. Translate or clamshell?
Engineering for VTX • Decision on mounting scheme requires engineering • PHENIX hiring engineer to replace P. Kroon (retiring) • Work on PHENIX central region, which includes VTX • Engineering specific to VTX will be done at LANL(?) • In consultation with new PHENIX engineer • Point of contact with HYTEC
VTX Design Issues • Circulated spec sheet compiled by D. Lee for CDR: • Heat Load (mainly due to readout chips): • 0.35 W/cm2 for strip layers; Vince concurred • 0.70 W/cm2 for pixel layers; Hiroaki concurred • Consistent with nos. in proposal • Mechanical tolerances/distortions: < 25 mm • Disassembly/configuration options: D. Lee has discussed modularity with HYTEC • Need to finalize before next round with HYTEC
VTX Auxiliary Systems • Services routed radially at the pole tips: • Power for Si detectors (proper grounding & isolation): • Si HV & LV power supplies (Stony Brook & RIKEN) • UPS (BNL) • Cooling system for Si • Dry Air System • Bleed boil off from LN2 buggy into enclosure • Radiation Monitoring • TLDs & Chipmunks
Routing for Services From: van Hecke Power, cooling and signal services are brought in at both ends, using the entire perimeter.
Infrastructure for VTX • Electronics racks • Platforms above central magnet • Cooling for electronics • Power for aux sys (proper grounding &isolation): • Clean & dirty power • 110V & 208V • Ballpark estimate: pixels draw 60A and strips draw 400A • UPS
VTX Design Issues Revisited • Circulated revised spec sheet: • Cooling system operating temperature: < 10o C (Junkichi) • Current draw from Junji and Dave: What’s correct?