Brahms Update June 9, 2000
RHIC
The commissioning of the RHIC accelerator is moving forward, sometimes at a rapid pace and at other times seemingly with little to show for in terms of available beams, yet to collide, for the experiments use. It is though moving much closer. The very near term program is to establish collisions in the IR with the present luminosity (i.e. 6 bunches with about of total 3-5.10**8 Au ions with in general yellow beam lower than blue. At this kind of intensity the expectation is a collision rate of about 1 per 20-100 sec. This is clear not enough for a physics program, but good enough for publicity.
Once collisions are established work will continue of two main areas I) improving luminosity and stability and II) start commissioning the detectors. An open period for si-installation (Phobos, Phenix) and misc. installation (Brahms) is planned about 2 weeks after collisions are established. This Open period will most likely by now falls at end of June or early July.
BRAHMS
The front TPC was removed from the IR several weeks ago to undergo a simple repair for a shorten wire on the gating grid. It has been in the laboratory for a while and wasso used for testing and tuning the gating grid pulser. This now works satisfactory for MTP1. By chance RHIC needed an access to fix a cooling problem today e got a two-hour access. This allowed us to re-install TPM1, connect and check-out the readout. The gating pulser has yet to be installed.
The TOFW panels in the mid-rapidity has also been brought up, and incorporated in the readout and monitoring programs.
Single beam and dual beams both at injection and at gamma of 30 has been used to setup the trigger electronics, setting timing widths to create a trigger and scalar count that is both sensitive to collisions but relative insensitive to the beam gas interactions that dominate overall rates.
The experiment is increasingly being manned continuously primarily to tune and setup detectors and take runs under stable conditions. The runs at this point serve mainly to understand background and develop analysis software.
Example of background event in MTP2 (from yellow beam between Beam-Beam and DX).
Taken June 9, 2000 Run-1286. Event 83285.