From: Dana Beavis (Beavis@sgs1.hirg.bnl.gov)
Date: Fri May 23 2003 - 14:56:57 EDT
----- Original Message ----- From: "Flemming Videbaek" <fvidebaek@optonline.net> To: "Dana Beavis" <beavis@bnl.gov> Cc: "Jens Jorgen Gaardhoje" <gardhoje@nbi.dk> Sent: Friday, May 23, 2003 1:54 PM Subject: Fw: Decision on Final FY03 Polarized Proton Running Conditions > Hi Dana > Could you forward this message to brahms-l@bnl.gov > I cannot o this from home > Flemming > > ------------------------------------------------------ > Flemming Videbaek > Physics Department > Brookhaven National Laboratory > > tlf: 631-344-4106 > fax 631-344-1334 > e-mail: videbaek@bnl.gov > > ----- Original Message ----- > From: "Kirk, Tom" <tkirk@bnl.gov> > To: "Busza, Wit" <busza@mit.edu>; "Hallman, Tim" <Hallman@bnl.gov>; "Videbaek, Flemming" <videbaek@bnl.gov>; "Zajc, Bill" > <zajc@nevis.columbia.edu>; "Lowenstein, Derek" <lowenstein@bnl.gov>; "Roser, Thomas" <roser1@bnl.gov>; "Pile, Phil" > <Pile@bnl.gov>; "Rusek, Adam" <rusek@bnl.gov> > Cc: "Steadman, Steve" <Stephen.Steadman@science.doe.gov>; "Aronson, Sam" <aronson2@bnl.gov>; "Chaudhari, Praveen" > <chaudhari@bnl.gov>; "Paul, Peter" <ppaul@bnl.gov>; "Kirk, Tom" <tkirk@bnl.gov> > Sent: Friday, May 23, 2003 11:53 AM > Subject: Decision on Final FY03 Polarized Proton Running Conditions > > > | . May 23, 2003; 11:50 am > | > | To: RHIC Spokespersons and RHIC Program C-AD Managers > | > | From: T. Kirk, ALD-HENP > | > | Subject: Final FY03 Polarized Proton Running Conditions > | > | The FY03 Polarized Proton RHIC run has been extended by > | two weeks from the planned duration of 8 weeks to 10 weeks > | total. The net data gain was NOT two weeks but was an attempt > | to achieve two incremental data weeks for the spin measurements > | and secure a successful physics yield of events for the FY03 run. > | > | Very recently, the machine physicists have clearly established > | that the per-IP luminosity depends inversely on the number > | of IPs in collision. Specifically, it will be possible > | to achieve a factor of two in the integrated luminosity of > | STAR and PHENIX, the two experiments that are performing > | longitudinal polarization experiments, for the remaining run > | time if the IPs at PHOBOS and BRAHMS are taken out of collision. > | > | A decision to terminate PHOBOS and BRAHMS running at this point > | and continue only STAR and PHENIX for the last week of the run > | was contemplated by me and communicated to the spokespersons > | of BRAHMS and PHOBOS for their comments. The meeting to discuss > | this change in running was carried out with Wit Busza (by phone), > | Flemming Videbaek, Derek Lowenstein, Thomas Roser, Phil Pile, > | Dave Hofman and myself this morning from 9:30 - 10:00 am. Both > | PHOBOS and BRAHMS spokespersons made convincing statements about > | the value of continued running for their experiments. This > | value was not contested but had to be compared with the loss > | of spin physics for STAR and PHENIX that the factor of two loss > | of luminosity would obtain if the run continued with 4 IPs active. > | > | After considering all the technical points and the statements of > | the spokespersons, I have decided to terminate PHOBOS and BRAHMS > | running today in order to maximize the integrated luminosity > | of STAR and PHENIX for the remainder of the run. PHOBOS requested > | a three-hour run with their magnet off to make some critical > | measurements. This request will be honored during the next store. > | After that, both PHOBOS and BRAHMS will shut down and end this > | run. > | > | This decision was taken with the sober realization that it has > | made a significant negative impact of the outcome of the physics > | that can be realized by PHOBOS and BRAHMS, but with the belief that > | the gains for STAR and PHENIX more than offset this loss given the > | initial physics results they can reasonably expect to make with > | the additional integrated luminosity using longitudinally polarized > | beams. > | > | The decision was also taken in recognition that the reduced number > | of running weeks foreseen in the FY04 President's Budget will likely > | allow only a single beam species to be run next year and that this > | run is likely to be using Au-Au. This second observation emphasizes > | the importance of reaching as far a possible this year in obtaining > | spin physics results in STAR and PHENIX. > | > | This message may be distributed as desired by the addressees. > | >
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