Notes on experimental program for the next about 10 days of RHIC beam development and experimental setup as was discussed during todays 1.30pm meeting. The plans for this weekend is to re-establish stables ramps, provide collisions for experiments with only minor beam-studies. This will be with 6 bunches in Y+B. Dear Collaborator, I am summarizing the discussion we had this afternoon for near term goals. It should be reviewed on the Monday meeting following the weekedns data collection, hopefully good. Flemming ---------------------------------- What rates can be expected? The approximate formulae for collision rates is N(ZDC)/sec == I(Blues)*I(Yellow)*Nbunches *3/40 where I(Blue) number of Ions per bunch For typical value achieved so far this will give N ~ 2-20 /sec; Once the machine goes to 60 bunches the intensity should be 20-200/sec. Last years rates at 10% luminosity was ~ 150/sec. Shifts should evaluate the rate from actual values given on screen i.e. I(Blue)= TV-value / Nbunches (6) If values are much smaller than this, and if smaller than other exp call main control and discuss issue (i.e. ask for MCR activity, request steering to up the rate) Run length To get a useable run for the spectrometers and DC one needs integrated zdc-triggers in orders or 200,000 to 400,000 i.e with 6 bunches hours of beam (1 hour may yield up to 36,000 events). First goals a) Zero field run for MRS @ 90 deg. Goal 1-2K tracks require ~400K events. b) Once completed same amount for A-polarity c) Collect data for DC in present FS configuration i.e. 6 deg, and FFS at 15 deg. All no field running to check all chambers T3-T5 and get straight througs. FFS is not so usefull for two reasons I) T1 is still in conditionin mode and ii) rates at 15 deg are very low. (400K events) Second Goal This second step is unlikely to be complete before end of weekend, but if goes well. Once c) is done move FS to 6 deg for both sections FFS and BFS. Goal is to commission t2-RICH; thus turn have magnets at 1/5 max field. Ramiro will provide proper values to set. At 6 deg this will pick the yield around <pt> of ~ 450 MeV/c. On MRS collect high statistics on 90 deg 2A/2B and 4A/4B to check out systematic features with new tof wall. By high statistics is meant about 1M events per setting. This is not quite enough for a physics result with the still wide vertex, but should enabled to setup timing for TOFW, check tracking etc. Once T1 is alive one can consider to move to 4 deg, to have at least acceptance overlap with the 2000 data settings both A and B polarity. One should record about a factor od two more statistics with A pol (i.e negatives) than for B positives. ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov
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