1 HFT, a High Resolution Vertex Detector for STAR Wieman RNC LBNL Thursday, May 17, 2006

2 Topics  Requirements and features of the HFT  CMOS APS Detector Technology uAPS Introduction uBasis for Technology Choice uR&D plan, a 4 ms chip followed by a 0.2 ms chip uDetector Verification in STAR Environment  DAQ readout approach  Mechanical Concept uMinimum mass ladders uSingle end support  Stable reproducible spatial alignment  Rapid insertion and removal uThin beam pipe system  Project Status  Latest TAC Review

3 Requirement Topologically detect low momentum D’s in the environment of high multiplicity heavy ion collisions and high luminosity at RHIC in the most effective manner consistent with available resources Special requirements prompts use of new technology

4 Some HFT features Pointing resolution(13  12GeV/p  c)  m LayersLayer 1 at 1.5 cm radius Layer 2 at 5 cm radius Hit resolution8.7  m Position stability10  m Radiation thickness per layer X/X0 = 0.28% Beam pipe radiation thickness X/X0 = 0.14% Number of pixels98 M Raw data rate31 GBytes/sec Stored data rate after sparcification 90 MBytes/sec Integration time (affects pileup) R&D phase 4 ms Final detector 0.2 ms Rapid installation and replacement Reproducible positioning

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6 Basis for CMOS Technology Choice  CMOS APS technology uAdvantages:  Relatively RAD hard  Available through multiple standard CMOS foundries  Inexpensive commercial thinning  Good success rate making working detectors by many institutions  Excellent position resolution and fine granularity  Partnered with the leading institution, IReS (now IPHC) in Strasburg  Young technology, can expect considerable growth in capability uDisadvantages:  Young technology for vertex detectors, currently no installed systems  Limited signal to noise  Current designs have relatively long integration times, i.e. potential pileup at highest luminosities

7 Si Pixel Developments in Strasbourg  Mimosa – 1 u4k array of 20  m pixels with thick epi layer  Mimosa – 4 uIntroduce Forward Biased Diode  Mimosa – 5 u1M array of pixels, 17  m pixels using AMS 0.6 process uUsed at LBNL for ladder development  Mimosa – 8 uFast parallel column readout with internal data sparsification  MimoSTAR – 1 128x128 pixels using TSMC 0.25  MimoSTAR – 2 128x128 pixels using AMS 0.35 –Duct tape these to the STAR Beam Pipe for 07 run  MimoSTAR – 3320x640 pixels using AMS 0.35  MimoSTAR – 4 640x640 pixels production run  Ultra – 1  Ultra – 2

8 IReS MIMOSTAR chips  MIMOSTAR1 (0.25  m TSMC) uReduced size prototype but sophisticated chip with complete functions for operation in a real detector system uEverything operating except pixel signal because of 0.25  m TSMC feature: Unexpected short signal decay time compared to theory and AMS experience.  MIMOSTAR2(0.35  m AMS optical process) uTested in beam u e most probable for Min-I u10-12 e-rms, noise. uSignal decay time 100 ms

9 Ultimate (fast APS detector) - good for high luminosity at RHIC  Submitted requirements list to IReS. In discussion Technology MIMOSA8 Ladder active area 2cm  20cm Pixel size 30  m  30  m ~Pixel mapping on the ladder 640  6400 Minimum operating distance from beam1.5 cm Power  100 mW/cm 2 Operating temperature  30  C Integration time[1][1]  0.2 ms Mean silicon thickness  100  m Readout time  1 ms Efficiency (min I)[2][2]  98% Accidental cluster density  50/cm 2 Binary readout, number of threshold bits[3][3] 2 Radiation tolerance [4][4]  124 kRad Number of conductors supporting the ladder (10 chips/ladder)[5][5]  140 Triggered readout, maximum trigger delay[6][6] 2  s

10 Readout system – Triggered - Standard STAR Structure – using existing daughter boards  In Beam System test, two partial ladders with MIMOSTAR2 chips next run (focus of this year’s effort)

11 Event size and data rate, data reduction crucial Some numbers: Item number bits/address18 inner ladders6 outer ladders18 half chips per ladder20 ave hits/half chip, inner, L = ave hits/half chip, outer, L = Only the hit addresses generate significant data volume. The totals are: Item number Event Size90 kBytes Data Rate at 1 KHz event rate90 Mbytes/sec The HFT event size is significantly smaller than the TPC which has an event size of 2 MBytes for central Au+Au Raw data rate: 31 GBytes/sec Reduction 1/340,000

12 Main R&D effort this year  Build two ladders with two MIMOSTAR2 chips each u( each chip 4 mm x 4 mm)  Install chip to chip (for coincidence) at an intersection region, preferably STAR  Operate with DAQ 1000 ALTERA/NIOS/SIU-RORC based system and STAR trigger interface  Gain operating experience and obtain track density numbers at small radius Our engineers working closely with STAR DAQ expert, a benefit to us as well as helping STAR by expanding DAQ expertise

13 Mechanical  Mechanical support  Beam pipe

14 HFT Mechanical requirements Full self consistent spatial mapping prior to installation Installation and removal does not disturb mapping Rapid replacement 10 Micron stability (mapping of BarBar with visual coordinate machine)

15 Conceptual mechanical design

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17 Kinematic mounts See: Record position reproducibility 1 nm 200 nm reasonable reproducibility expectation

18 Cost and Schedule/Availability of Funds  The BNL Mid-Term Plan includes funding for the HFT Proposed HFT Profile K 1M 800K+300K2.5M 2.5M R&D R&D R&D+Const Const Const  The proposed schedule of funds makes Mimosa-8 technology available in time to complete the project uThe project has the 200  sec readout chip as the final goal  The R&D profile allows us to complete the development of the MimoSTAR chips and to readout data with a 4 msec frame rate uDo extensive R&D and testing with MimoSTAR-4 chips uMount them in STAR uUse the real beam pipe, real beam rates, real background uUse the real mechanical insertion device  The Construction Profile allows us to complete the development of the Mimosa-8 style chips and readout with 200  sec frame rate uThe final detector will be based on Ultra-XXX chips

19 Project Labor Summaries  Engineering labor ~ 13.5 FTEs  Technical labor ~ 7.5 FTEs  Management & Management support ~ 3 FTEs  Costed Labor uProject~3M  Contributed labor uBNL ~1M uLBL ~2M

20 Project Status  Proposal submitted to STAR, waiting for go ahead  BNL management has penciled in a budget and time line  DOE is aware of plans for the HFT project

21 Report of the Technical Advisory Committee for RHIC Detector Upgrades March 14-16, 2006 Committee members: M. Cooper (LANL), C. Haber (LBNL), B. Mecking (JLab), J. Proudfoot (ANL), V. Radeka (BNL), R. VanBerg (U. Penn, not present at the review), J. Va’vra (SLAC) Heavy Flavor Tracker Physics Motivation The proposal to add a heavy-flavor tracker (HFT) to the STAR detector will significantly enhance the capabilities of STAR in the mid-rapidity range. The detection of a displaced secondary vertex will cleanly identify the production of heavy flavors from the topology of the event alone. For example, D-meson decays can be identified without the need for kaon identification and without combinatorial background. Detector Concept and Technology The proposed APS technology is the most promising choice for high granularity, low radiation length, and low power dissipation vertex tracking in an environment such as RHIC. The proposed design configuration maximizes the solid angle coverage while keeping the number of detector layers and the area of silicon at a minimum. It is assumed that the small beam pipe diameter will be consistent with reliable machine operation. The overall concept and implementation plan is well thought out. This is a cutting edge technology, and it will be used for the first time on a fairly large scale in a large physics experiment. If successful, it will have a significant impact on future experiments. Highlights from TAC review

22 Cost, Schedule, Manpower This is a well planned project which recognizes that it has limitations in the available manpower and funding, particularly with respect to mechanical engineering. Recommendations 1. This R&D effort should proceed. The proposed schedule for realizing a working detector is very tight, and, as the STAR project manager noted at this review, the funding profile shown in BNL’s Mid-Term Plan for RHIC is not well matched to the current plan for R&D activities. BNL and STAR should work with DOE to make realistic plans for this valuable project.