STAR NEWSLETTER NUMBER 44

STAR Newsletter for May 1997

31 May 1997

Editor: Bill Christie, BNL

From the Spokesman:
STAR Project Summary (from the last monthly report)
Notice of Meetings
Christies Corner
Comings and goings at STAR
Employment opportunities
STAR notes since the last newsletter

1. From the spokesman:

Reported by John Harris

May was a very busy month for "official" STAR meetings. A meeting to discuss STAR Off-line Computing was held on May 8-9 at LBNL. This meeting of STAR experts and "would-be" experts was called to take a close look at the STAR Offline Computing Model and our potential Offline Computing resources, namely computing at individual STAR institutions, the RHIC Computing Facility and the LBNL NERSC facility. I found the presentations interesting and the discussion open and refreshing. It was good to see the experts in STAR deeply involved in this topic. As a consequence of the meeting, I have appointed a STAR Offline Computing Working Group of Torre Wenaus (chair), Bill Love, Doug Olson, Lanny Ray (secretary), and Thomas Ullrich. The charge to the working group is to evaluate the model (approach) for STAR Off-line Computing. This should include the plan for implementation of hardware at the RHIC Computing Facility (RCF), individual institutions of STAR and the proposed STAR Offline Facility at NERSC/LBNL. I requested that a recommendation be made to me of the model and plan that best suit the offline computing needs of STAR (using the STAR requirements presented in the ROCOCO II report) by the time of the pre-RCF-review meeting of the RCF with the RHIC experiments in mid-June. I expect that the productive work of this meeting will continue to the benefit of STAR.

On May 19, the Run-Time Committee (RTC) met at BNL. The Physics Working Group convenors (see next paragraph) made presentations on the run-time requirements necessary to take statistically meaningful data in the first year of the STAR experiment for the physics observables addressed by their working groups. Jim Carroll, chair of the RTC, presented an initial strawman run plan. Due to the limited luminosity in the first year or two of RHIC operation and the need for beam development time by the RHIC accelerator group, a STAR scenario is emerging for RHIC operation with full energy Au + Au (possibly at the beginning and at the end of the first year), and possibly a change to lower energy or lighter beam nuclei. The RTC is expected to present their report at the July Collaboration Meeting.

On May 20, the Physics Working Groups (PWGs) met at BNL. In the meeting most of the individual groups met in the morning. In the afternoon there was a plenary session with reports from the PWG convenors followed by the event-by-event working group meeting. It is obvious from the meeting that there is still a need for effort from the collaboration since many physics topics and general software items remain unaddressed. If you have any questions about topics, please contact the PWG convenors:

Spectra (W. Llope, Rice)
Strangeness (K. Wilson, Wayne State; P. Jones, Birmingham)
High Pt (T. LeCompte, ANL)
Spin (G. Eppley, Rice)
HBT (J. Cramer, Washington)
Peripheral Collisions - Two-Photon Physics (S. Klein, LBNL)
Event-by-Event (I. Sakrejda, LBNL)

For questions about simulations and applications software please contact Lanny Ray (Texas). Also, please note that there will be a plenary session featuring STAR simulation results at the upcoming STAR Collaboration Meeting at BNL in July.

The Open Discussion on the STAR Trigger was held at BNL on May 21. I would like to thank the STAR Physics Working Group convenors for their presentations of the trigger needs for the physics of interest to their working groups. I felt that it was very productive to put things out on the table and to discuss them. I have sent out my summary of the discussion to the STAR Council and have solicited their input and that of the Collaboration prior to June 13.

I would like to remind you of the STAR Collaboration Meeting which will be held July 20-26 at BNL. There will be a full week of activities. A preliminary calendar of events is:

Sunday, July 20 - STAR Software and Offline Computing
Monday, July 21 - Parallel Sessions
- STAR Detector Working Group Meetings
- STAR Primer for Students and New Junior Members
Tuesday, July 22 - Parallel Sessions
- Physics Working Group Meetings
Wednesday, July 23 - Plenary Sessions
Thursday, July 24 - Plenary Sessions
Friday, July 25 - Plenary Sessions

This calendar could still change in detail. A more detailed agenda will be s ent out in mid-June.

2. STAR Project Summary

Excerpted from the STAR Monthly Report for April 1997.

Project Management Summary and Highlights

While progress isn't as apparent as in month's past, assembly and installation efforts are still moving forward productively. The magnet steel got painted blue, but more importantly, it is ready to accept the coils when they begin to be installed in May. The TPC's IFC is off its mandrel and lots of small but important details are being successfully worked out. Sector installation and field cage hi-potting will begin shortly.

The magnet power supply contract was awarded this month. Pole tip trim coil bids are out and pole tip support drawings are soon to be complete. All of the FEE components, except the printed circuit boards, are on order now for the 96% build. The system test is progressing with more and more hardware being integrated all the time. Eight CTB trays were delivered at the end of April. These trays have production mechanical components but not quite production electronics.

An electrical safety review of STAR took place this month (April 22nd). There were no surprises during the review; we're waiting for the committee report.

Torre Wenaus has agreed to take over the role of computing subsystem manager from Bill Love in July. We are happy to have Torre join us.

TPC Summary and Highlights

The fabrication of the IFC is proceeding without major problems. All trace to trace resistances on the outer skin have been brought up to specification, > 2G-ohm. The IFC was successfully moved from the lathe to the cantilever support and subsequently the steel and foam mandrel were removed. Production of the laser raft covers has begun in earnest. Installation of the east side resistor cover, high voltage cable cover and one laser raft and cover has been completed successfully. The inert gas supply system is complete and operational. Contamination problems with the nitrogen and argon manifolds have been solved and the system has been thoroughly "canary" tested. The methane supply is complete, tested and operational. A schematic of the TPC cooling supply system has been completed. Component type, size and material selection for all major items except the reservoir and IFC air to water heat exchanger has been completed.

Magnet Summary and Highlights

Contracts have been awarded for the magnet power supplies with the transformers being supplied by NWL and the rectifiers by Microamp. Delivery of these components will meet the installation schedule. Pole tip trim coil bids are due the first week of May. Delivery of the pole tips continues to be a transportation problem for the vendor.

Electronics Summary and Highlights

Systems Test

Much time this month was spent taking data with the four readout boards, one of which includes a plug-in expansion to accommodate the full 36 FEE cards. The water chiller was connected and made operational, allowing for studies of electronics stability. Studies were done with cosmic rays and pulser data and no major problems were encountered. No excess noise was seen nor were there problems with crosstalk between boards. Studies were also done of the wire signals, and signal and noise measurements taken with a FEE card modified to read wire signals.

To simplify data taking and prepare for the cosmic ray tests, the trigger was greatly simplified. The STAR trigger hardware and processors for this case have been replaced with a NIM-based trigger.

Front End Electronics (FEE)

The first readout board plug-in expansion was debugged, and is now being used in the system test. The main readout board required a higher current regulator to handle the increased current draw. A decision was made to install an overtemperature switch on each board to protect the board against a loss of cooling water.

The other plug-ins are assembled but not yet tested. The full complement of 10 main readout boards has also been assembled, and are now being debugged.

All of the other parts for the 5000 FEE cards in the 96% build have been ordered. The circuit board order will await the completion of more detailed stability tests.

Data Acquisition (DAQ)

Extensive testing of the cluster finder ASIC prototype chips took place. As a result, an order was placed for enough of them to meet the needs of the TPC, SVT, and anticipated FTPC.

Prototyping of the high-speed data delivery system (fiber optic receiver to mezzanine cards) continues; the test board is in layout.

Testing of SUNNY, the prototype mezzanine card, continues. The SDRAM and CPU are completely functional. The CPU now boots a VxWorks image which has been placed in its memory (SDRAM) via the PCI bridge while it is held in reset. The control logic for the VRAM still needs to be debugged.

Trigger

Eight trays of CTB have been delivered to LBNL for the local cosmic ray tests. These trays each hold two scintillators, Hamamatsu photomultipliers, Cockroft-Walton type high voltage supplies, and simple anode outputs for coincidence triggering.

All trigger study software is now up and running in STAF. The xdf format events are ready to start production runs in GSTAR.

Slow Controls

Several EPICS databases pertaining to the TPC readout boards have been updated to accommodate the new "16-bit two's complement" data format representing the housekeeping voltages and temperatures. The converted data has also been placed into a separate set of EPICS process variables for readout by the system test data acquisition system.

A complete sample of fake ADC data (1.15 MB) was written to, and read back from the event buffer of the new readout board over the HDLC link. The read back was timed at exactly 3 minutes per readout board.

A prototype EPICS display screen has been developed to monitor the TPC resistor divider chain current. To enable proper functioning of the associated GPIB driver, a new vxWorks kernel that incorporates A24 memory management was created. The new system is stable and works in conjunction with other competing processes.

Computing Summary and Highlights

Simulations

A status report of the STAR simulations framework and several hot simulations topics was presented to the STAR Technical Committee by W.J. Llope and B. Christie. The simulations of the effects that the beam pipe design has on the TPC, SVT, and FTPC tracking performance are near completion and are presently being written up. The SVT standalone tracking and the SVT/TPC matching are now up and running in STAF, and work continues to 'fine-tune' these codes.

Both the TPC fast (tfs) and slow (tss) simulators have been tuned and reinstalled in order to better reproduce the space point position resolutions obtained for tracks with small to moderate pad crossing angles from analysis of the system test cosmic ray data. Both simulators now handle the zero magnetic field condition; both are considered ready for use in simulations for the upcoming cosmic ray tests.

A csh version of the GSTAR geometry setup script (setup_gstar.csh) is now available.

The TPC geometry (tpcegeo) was updated to fix problems in the number of pads specified for rows 10, 13, and 38.

A major bug that raised the mid-rapidity radiation length of the SVT by about 1% of a radiation length was fixed.

GSTAR was benchmarked on the new RHIC machine rsgi05 (and SGI Origin R1000) for central Au+Au events with all STAR detectors on and all physics on.

Analysis Software

A new version of the TPC pad monitor was installed which reads data from up to six RDO boards and which handles "black" events (from one RDO board) as well as zero suppressed events.

Two modules and their associated KUIP macros were developed and installed in package tfc (TPC data format I/O, gain corrections and pedestals) which provide pixel to coordinate space location mapping and which handles the new TPC System Test raw data format as defined in SN0282, as well as geometry events, pedestal calculation and subtraction, and gain calculation.

The TPC cluster finder and space point reconstruction package, tcl, was updated and installed in order to include a new weighted mean algorithm (in addition to the fixed 3-pad method) for determining space point positions across pad rows.

The TPC tracking and space point evaluation package, tte, was upgraded and installed in order to include better parameter initialization and calculation of the closest distance of tracks to the origin.

The SVT dE/dx and PID module, spr, was upgraded to gstar/g2t and STAF and installed in the library.

A new Forward TPC analysis package, fde, was created for the study of dE/dx and possible PID capabilities for low momentum pions.

The EMC simulations and analysis package, ems, was upgraded to include recent TPC and global tracking macros. Also an EMC/Shower Maximum detector electron and photon finder module was developed and installed in ems.

A feature was added to the global track refitter package, egr, to permit SVT space point removal (global fitting outliers) in the space point to global track fitting process.

Software Infrastructure

A talk on the STAR analysis framework was presented at the "Computing in High-Energy Physics, 1997" conference and was well received.

There was also development on interfacing between STAF and ROOT. Both an example program and an example STAF service package were developed which translate STAR data tables into ROOT objects and histograms.

On-line software

The on-line software group prepared for the cosmic-ray tests of the TPC at Berkeley. The run control program was modified to account for changes in the mini-daq which accommodate reading out a full sector's worth of electronics.

3. Notice of Meetings:

STAR Collaboration Meeting, July 20 - 26, at BNL. For further information, please contact John Harris at Yale.

4. Christies Corner

Greetings from Long Island. May has been a generally pleasant month here on Long Island. The temperatures were a few degrees cooler than normal for May and the precipitation was also a bit lower than normal. All of the deciduous trees now have their leaves and the Rhododendrons are in bloom.

In addition to the various STAR meetings that were held here at BNL in May the STAR Electromagnetic Calorimeter group was here to use the AGS test beam. The EMC tests included getting data with the new Megatile mechanical design for the barrel calorimeter and testing two variants of the Shower Maximum detector. By all accounts the test beam time went well, all of the detectors worked, and alot of data was collected.

The major activity at the assembly building during May was the start of the coil installation in the STAR magnet. So far this installation has gone very smoothly. If you look at the picture of the Assembly building (via the STAR WWW page) you can see that two of the main coils and one of the space trim coils have already been installed. The coil installation will continue to be the major activity at the assembly building through June and into the first few weeks of July. The first of the two large iron magnet poletips is sheduled to arrive at the assembly building the first week of June. The second of these 75 ton poletips is scheduled to arrive in the second week of June.