Hi, The instruction just call for one polarity I absolutely agree with this - see my earlier estimates as of a few days ago (based on the 1/2 field spectra)- I do not think there is much discussion about that. In regard to the 22 GeV it should be pointed out that it is not so likely one can get results out of that. Let me point out a few issues that make it very difficult. This does not mean we might not try but do not expect anything -- beam quality Intensity ~ 100-500* 100+100 gev -> a few collisions per second. Store time ~ 20-30 minutes -- The ZDC effeciency is much lower - The fermi cone is ~ 15cm radius and ZDC coverage +-5 cm. The beam beam counters sit at eta > y(beam) and the effeciency is not really known. Since the ZDC will be in-efficient means one has to trigger on beam-beam alone? (tr-1) So how can one normalize when you have an unkown trigger effeciency ?? Idea's (that only involves existing setup are welcome. Flemming ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov ----- Original Message ----- From: Jens Jørgen Gaardhøje To: brahms-l@bnl.gov Cc: gardhoje@nbi.dk Sent: Saturday, November 17, 2001 2:41 PM Subject: Re: run status Hello friends As concerns the run. -Ian and I discussed the 12 deg statistics yesterday based on a fisrt analyis of a run at the present setting. It is still to early to really evaluate the present run, but it seems likely that we will not have time to do 2 polarities at this angle and high field setting. We will need to make a final decision by monady or tuesday. -I would think that we should run at 22 GeV. If nothing else we should be able to get the multiplicity distributions. regards JJ ________________________________ Jens Jørgen Gaardhøje Assoc. prof. Dr. Scient. Chair Ph.D: school of Physics NBI.f.AFG. (secretariat. 35 32 04 41) Chair science committee. UNESCO Natl. Commission. (secretariat. 33 92 52 16) Office: Niels Bohr Institute, Blegdamsvej 17, 2100, Copenhagen, Denmark. Tlf: (+45) 35 32 53 09 Fax: (+45) 35 32 50 16 ________________________________ ----- Original Message ----- From: Flemming Videbaek To: brahms-l@bnl.gov Sent: Saturday, November 17, 2001 5:10 PM Subject: run status The AuAu running is going into the last 8 days of running. The machine has run fairly well in recent eve+nights and this is expected to continue over the weekend. The yellow beam still has lifetime problems, and and 12 hour beam development period is scheduled from Monday morning 6.00 am. - Please turn magnets to 0 field, and standby at that time. - The running at 12 deg 2/3 fields has started (.66 M) collected aim up to 810M at 2/3 field (and at least 4M) - 40 deg 1.5 M for HBT is complete. - The high statistics program at 90 deg has started - there is an issue if the retracted position (i.e. reduced solid angle by 25%) is an issue. In the previous e-mail I requested, and will like to repeat a call for un-finished business. e.g angles, fields in the exsisting program that needs repeating, or special runs that enhanches our understanding of present data or in preparation for upcoming runs. So far there are a couple of items - Michael M. requested a short run ~100K minbias data with reduced ZDC HV to understand tube saturation. - I will like to take a several hours to develop the H1/H2 trigger setup, probably middle of the week (though not Thursday) - Michael suggested we study the 22GeV beam, not so much to take physics data, but to gain insight how to deal with lower energy beams in preparation for the future. E.g. ZDC threshold/settings/response triggering. He is planning to come to BNL for the weekend for this purpose.
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