Nuclear Phase Transition Diagram Mar RHIC Monday Meeting T. Satogata DOE NSAC Long Range Plan … a whole page! (one out of 14)

Apr Time Meeting T. Satogata2 Low Energy Parameters Au nom injection Au Au 2008/10 Au 2010  s NN [GeV] Baryochemical potential μ B [MeV] Beam energy [GeV/u] Beam kinetic energy [GeV/u] Relativistic  Relativistic  Momentum [GeV/c] Rigidity B  [T-m] RF harmonic number RF frequency [MHz] Max beam size (95%) [mm] Beam/ring time available--27/30.5h(1-2d?)4wks(2wks) Luminosity [x10 23 cm -2 s -1 ](20-80) (~10)(~30) RHIC full aperture at  max is 113 mm; at 7.7 GeV this is ±3.3 σ max (95%)  B from Andronic, Braun-Munzinger, Stachel, Nucl Phys A 772, 2006)

7.7 GeV Low Energy Program Schedule  Sun Apr 18 eve: AGS E=3.85 GeV/u setup (on synchro) Mon Apr 19: RHIC TPL, checkoff list in progress  Thu Apr 22 08:00  s NN =7.7 GeV start 12h+ maintenance: Q7/defoc sext reversals, RF work, etc First collisions seen early Fri Apr 23  ~Sat Apr 26: Start  s NN =7.7 GeV physics (4 weeks) Limited APEX: no RHIC beam above E~5 GeV/u Collisions at both STAR/PHENIX (h=369) Expected refills every ~20 min; event rates of “a few Hz” Will be using collimators for first time in low energy ops Will use refill time, # bunches, intensity to optimize lumi  Mon Apr 28: Resolve PHENIX DAQ clock problem Allows PHENIX to use all data, faster store turnaround Apr Time Meeting T. Satogata3

7.7 GeV Beam Intensity and Collisions Apr Time Meeting T. Satogata4 compressed air failure Yellow QLI Accidental hysteresis; Blue QLI Injection tuning

(Some) 7.7 GeV Low Energy Challenges  Tandem and Injectors High Tandem, injector availability/uptime required Tandem foils in MP7 were changed/refreshed in March Leaves little time for tuning, lowering losses, maxing lumi  Loss monitoring and radiation safety Will monitor losses daily, adjust operations as necessary Regular meetings to review, ensure that operations are localized and within safety limits  Luminosity monitoring Very low rates; clean collision signals from both detectors  Apertures, apertures, apertures AGS longitudinal, transverse emittances, collimation  No spring storms! Apr Time Meeting T. Satogata5

For Your Consideration…  Lower beta* Calculations indicate that 6-8m beta* might be feasible May give 20-40% integrated luminosity improvement Have to balance against beam losses in controlled areas  Moving to even shorter stores May give us 30-50% integrated luminosity improvement Requires loss review, impact evaluation by RSC  Collimation strategy is evolving Balance between injection efficiency, loss localization Perhaps a 10-20% integrated luminosity effect  Optimizing store turnaround time Shortening AGS cycle, minimize refill tuning Apr Time Meeting T. Satogata6