1 QM2006 D.I.Lowenstein RHIC : The Path Forward Presented to Quark Matter 2006 Shanghai, PRC Derek I. Lowenstein Brookhaven National Laboratory November 15, 2006

2 QM2006 D.I.Lowenstein The Present RHIC

3 QM2006 D.I.Lowenstein RHIC NSRL LINAC Booster AGS Tandems STAR PHENIX PHOBOS Jet Target RF BRAHMS RHIC – a high luminosity hadron collider Operated modes (beam energies): Au–Au 10, 28, 31, 65, 100 GeV/n d–Au* 100 GeV/n Cu–Cu11, 31, 100 GeV/n p  –p  11, 31, 100, 205, 250 GeV Possible future modes: Au – Au2.5 GeV/n (AGS, SPS c.m. energy) p  – Au*100 GeV/n (*asymmetric rigidity) Achieved peak luminosities (100 GeV, nucl.-nucl.): Au–Au 58  cm -2 s -1 (2x design) p  –p  35  cm -2 s -1 (7x design) Other large hadron colliders (scaled to 100 GeV): Tevatron (p – pbar) 25  cm -2 s -1 LHC (p – p, design)140  cm -2 s -1 EBIS Electron cooler

4 QM2006 D.I.Lowenstein Delivered luminosity and polarization during last 5 years (Q3) 15% 34% 46% 47% 65%  Expect x2 Au ion luminosity increase in the 2007 run

5 QM2006 D.I.Lowenstein The Evolution of RHIC

6 QM2006 D.I.Lowenstein Path Forward l Short term ( ) l Luminosity increase n Stochastic cooling complete n Increase number of bunches m >x2 for ions; >x2 for polarized protons l Mid term ( ) l RHIC II Phase 1 efforts completed n EBIS injector operational n Major detector upgrades completed l RHIC II Phase 2 efforts started n electron cooling construction started l Longer term ( ) l RHIC II completed l eRHIC Project started

7 QM2006 D.I.Lowenstein Goals for RHIC Enhanced Design Performance (2008*) 1.Au-Au L store average= 8 x cm -2 s 100 GeV/n 2.p  -p  L store average=150 x cm -2 s 250 GeV 3. P store average = 70% 4.60% of calendar time in store = 100 hours/week 5. *First 250 GeV p  -p  physics run currently scheduled for 2009.

8 QM2006 D.I.Lowenstein Stochastic cooling can counteract IBS by keeping the emittance constant while electron cooling will shrink the emittance. Improves RHIC performance by providing more luminosity (20-50%) improved vertex size, and longer stores and reduced number of refills. Improves productivity. Time domain (oscilloscope) and frequency domain (spectrum analyzer) measurements confirm cooling Cooling time about 1 hour Bunch profile before (red) and after (blue) cooling, Wall Current Monitor Schottky spectrum before cooling: blue trace Spectrum after cooling: red trace Stochastic cooling of a high frequency bunched beam has been observed for the first time.

9 QM2006 D.I.Lowenstein EBIS Injector Project l New RHIC preinjector system: EBIS replaces 30+ year old tandems n Joint DOE and NASA funded project. Construction begun in n Improves performance m Extends mass range to uranium m Allows for polarized He 3 injection n Commission in 2009 EBIS test stand

10 QM2006 D.I.Lowenstein The RHIC experiments have learned to utilize elemental QCD processes generated in the collisions themselves, such as… formation and transport of heavy quarks, and quarkonium bound states fragmenting jets from high energy partons high energy photons Typically these are rare probes: Future progress requires well-defined improvements in detector capability and machine performance. T. Ludlam q q Why RHIC II ?

11 QM2006 D.I.Lowenstein RHIC II electron cooling Electron cooling of ion beams l Increases the luminosity for heavy ions by a factor of ten l Based on a high energy, 54 MeV and 50 mamp, energy recovery linac (ERL) and a superconducting photoelectron gun l Preparing for DOE CD0 decision in early FY2007 Superconducting RF CavityAmpere Superconducting RF Gun

12 QM2006 D.I.Lowenstein Electron-cooling facility at IP2 ERL RHIC triplet Cooling region 100 m RHIC triplet ERL Electron cooling R&D

13 QM2006 D.I.Lowenstein A New Generation of DIS: High luminosity polarized Electron-Nucleon/Electron-Ion Collider Gluon and sea quark polarization The role of orbital angular momentum Gluon momentum distributions in nuclei Gluons in saturation The color glass condensate Electron-proton collisions Electron – Ion collisions T.Ludlam Why eRHIC?

14 QM2006 D.I.Lowenstein eRHIC at BNL A high energy, high intensity polarized electron (and positron) beam to collide with the existing heavy ion and polarized proton beam. Would significantly enhance RHIC’s ability to probe fundamental, universal aspects of QCD E e = 10 GeV ( ~ 5-12 GeV variable) TO BE BUILT E p = 250 GeV ( ~ GeV variable) EXISTS E A = 100 GeV/nucleon (for Au) EXISTS At least one new detector for ep & eA TO BE BUILTAt least one new detector for ep & eA TO BE BUILT

15 QM2006 D.I.Lowenstein eRHIC Design Concepts simpler IR design multiple IRs possible E e ~ 20 GeV possible luminosity Ring-Ring design Linac-Ring design simpler ring design one IR possible less R&D effort luminosity 2 designs are under consideration

16 QM2006 D.I.Lowenstein eRHIC l Variable beam energy l Proton-to-uranium ion beams! l Proton, He 3 (EBIS) polarization l luminosity eRHIC Jlab12GeV eRHIC CM Energy vs Luminosity

17 QM2006 D.I.Lowenstein eRHIC ZDR Reviewed June 2005 (252 page document) Collaboration: BNL, MIT-Bates, BINP & DESY Goals: initial design, identify & investigate most crucial R&D problems for challenging luminosities and IR design

18 QM2006 D.I.Lowenstein Path Forward Schedule RHIC II

19 QM2006 D.I.Lowenstein RHIC design and achieved parameters Mode No of bunches Ions/bunch [  9 ]  * [m] Beam pol. L store ave [cm -2 s -1 ] A 1 A 2 L store ave [cm -2 s -1 ] A 1 A 2 L peak [cm -2 s -1 ] Design values (1999) Au – Au    p – pp – p   Achieved values (up to 2006) Au – Au    d – Au55120/    Cu – Cu    p – pp – p % 20   Enhance design values (2008) Au – Au    p – pp – p % 60   10 30