STAR Logo

STAR Newsletter #83

August 2001
Star Home Page
Editor: Howard Matis

Contents

  1. Spokesman's Column
  2. STAR Operations
  3. Detectors and Subsystems
  4. Period Coordinators Report
  5. Physics Working Groups (protected area)
  6. People: Comings and Goings
  7. Announcements
  8. Employment Opportunities

Spokesman's Column (John Harris)

No contribution this month.

STAR Operations (Bill Christie)

Collider update - The commissioning of the RHIC collider is progressing. As of late last week (~Aug. 3rd) the collider can routinely accelerate 56 bunches of Au ions into each of the RHIC rings. With the current intensity in the bunches, this produces interaction rates at STAR of about 100 Hz.

The next commissioning goal for the collider is to bring the storage Radio Frequency (RF) cavities online. Once completed, these storage RF cavities will shrink the length of the interaction diamonds in the interaction regions by about a factor of seven. This commissioning, while started as a background activity a week or so ago, got started in earnest today (Aug. 6th).

Once the storage RF cavities are commissioned, the final step for the collider this year will be to increase the intensity in the collider, to get the luminosity up near the design value. This will likely be a process that will extend for much of the run.

The Alternating Gradient Synchrotron (AGS) experienced a problem last Friday, as they had a mechanical failure in one of their motor generator (MG) sets. The diagnosis of the severity of the problem is underway. There is a backup MG set which is capable of fullfilling the needs of the RHIC program, but it can not support a parallel fixed target program with as high a performance specification as the MG set which was damaged. The impact on the fixed target program is presently being discussed.

STAR Update - The commissioning of the STAR detector has also been progressing. One of the items still to be finished is the gain calibration of the Central Trigger barrel. The process of taking a data set, getting it passed through reconstruction, getting it passed through Herb Ward's CTB calibration code, and getting a new set of HV values, takes about one day per iteration. It is estimated that about two more iterations are necessary.

The next item still to be brought online is the ability to place a vertex cut on the events accepted by the trigger at Level 0. This will be accomplished using the Time to Amplitude Converter (TAC) signals that we get this year from the first module on each of the ZDC detectors. The estimate is that it will take about one day to get this feature functional.

The last major task to commission is the final setting of the Multi Wire Chamber (MWC) readout used for the peripheral collisions program. The final timing of the signals into the trigger from the MWC electronics has to be determined. I'd estimate that this will take at least a few days, as it requires that we get access to the detector.

The commissioning of the EMC is not complete. The plan for completing this commissioning will be discussed, with the likely outcome that this commissioning will be done with a series of breaks in data taking as the Physics run gets going. A plan needs to be developed which will accomplish this efficiently.

Detectors and Subsystems

  • FTPC (from Volker Eckardt)

    • No contribution this month.

  • Slow Controls (from Mike Cherney)

    • No contribution this month.

  • EMC (from Thomas Cormier)

    • The first full crate of EMC electronics arrived at BNL last week. After final testing in the DAQ lab we will seek access to install this and whatever additional crates become available over the next few days. Each crate services 160 EMC towers producing digitized energies for Level-0 trigger and DAQ. A picture of the crate is below.

  • TPC (from Blair Stringfellow)

    • No contribution this month.

  • Level 3 Trigger (from the commissioning contingent)

    • No contribution this month.

  • Endcap EMC (from Will Jacobs)

    • Megatile production started again following an evaluation of first test production period in June.

    SMD module gluing and strip assembly began after successful review at ANL in early July. Test module fully instrumented with readout for comic ray tests.

    A successful review was held at TAMU concerning the PMT and MAPMT boxes to be located on the back of the STAR poletip. Pre-production PMT housings and prototype MAPMT housings have been assembled. It was hot in Texas.

    Plans for the final mechanical design review has initiated along with detailed discussions with anticipated manufacturer of Endcap hub and back plate. Right now we are shooting for a September start.

    Further prototyping of MAPMT FEE components and design of 4-card FEE_ADC and FIFO board assembly integral with prototype MAPMT housing and shielding box has been done this month.

  • SVT

    • No contribution this month..

  • RICH

    • No contribution this month.

    Period Coordinator Reports

    Useful resolutions for sane STAR running

    Don't be too cocky : you're going to get screwed Don't be too glum : things are going to improve

    Accelerator:

    Lots of problems and lots of unfulfilled plans. 14 out of 21 shifts- NADA for STAR. But ...Two great stores ( 6 bunches ) each lasting at least 5 hours with initial intensities at STAR of about 15-20 minbias triggers. Also, fast ramping to 100 GeV with acceptable losses not routine but not rare. To be done before STAR/RICH research plan can go into production:

    Go from 6 bunch to 56 bunch operation. On this Thursday afternoon (8/2) during Gary Westfall's watch there was a spectacular store at 56 bunches. The initial event rate at STAR was more than 100 minbias triggers per second. This store lasted 5.5 hours and near the end of the store the beam lifetimes were 1.5 days.

    RHIC is working with the RF to reduce the z length of bunches. The time estimate for this operation is about 2 weeks.

    STAR:

    Considerable progress on trigger issues over the past week. CTB calibration in progress.

    STAR magnet is running steady at full field. Cooling system yet to be tested under very adverse conditions (temperature and humidity ).

    - Chuck Whitten (22 July through 30 July)

    Physics Working Groups - (See the protected area)

    No contributions this month.

    This section contains summaries of the status of the physics working groups. These articles are in a protected area for STAR collaboration members only. This link uses the standard STAR account and password for physics results. If you do not have this information, please contact your council representative.

    People

    Announcements

    The Online operations web page, http://online.star.bnl.gov contains links used in the control room including ones to the RunLog Browser and an auto-updating page showing the current/latest run. Some of the links are likely not be viewable from outside BNL. As I find these out, I'll put a note to that effect beside the link.

    Jeff Porter

    Employment Opportunities

    Return to the Newsletter Index - Last Modified: Tuesday, August 14, 2001