Gatling Gun P rogram R eview

1. Gatling Gun Program Review Charge to the Review Committee Presented by Ilan Ben-Zvi Accelerator R&D Division Head Collider-Accelerator Department Brookhaven National Laboratory Gatling Gun Program Review, June 28th-29th, 2012

2. RHIC – a High Luminosity (Polarized) Hadron Collider Polarized Jet Target 12:00 o’clock 10:00 o’clock (AnDY) 2:00 o’clock RHIC PHENIX 8:00 o’clock RF 4:00 o’clock STAR 6:00 o’clock LINAC NSRL EBIS Booster AGS Operated modes (beam energies): Au – Au 3.8/4.6/5.8/10/14/32/65/100 GeV/n d – Au* 100 GeV/n Cu – Cu 11/31/100 GeV/n p – p 11/31/100/205/250 GeV Planned or possible future modes: Au – Au 2.5 GeV/n (~ SPS cm energy) U – U 100 GeV/n p – Au* 100 GeV/n Cu – Au* 100 GeV/n (*asymmetric rigidity) Tandems Achieved peak luminosities: Au–Au (100 GeV/n) 1951030 cm-2 s -1 p–p (250 GeV) 1501030 cm-2 s -1 Other large hadron colliders (scaled to 250 GeV): Tevatron (p – pbar) 1081030 cm-2 s -1 LHC (p – p) 2601030 cm-2 s -1

3. The Accelerator R&D Division • The C-AD Accelerator R&D Division is engaged in R&D towards eRHIC, a proposed electron – hadron collider based on RHIC. • The major R&D projects of the division: • The design of eRHIC, • The R&D ERL, • The Coherent electron Cooling POP experiment, • The 50 mA polarized electron source for eRHIC.

4. The Funneling Gun The high current polarized electron source is based on funneling 20 independent cathodes. We are funded by strategic LDRD to prove the feasibility of funneling as applied to a polarized electron gun. We are also interested in building up local expertise in the subject.

5. The charge to the committee • The Cathodes • Consider cathode preparation • Consider adequacy of the cathode cooling system. • The electrostatic design of the gun. • Is the gun design is electrostatically conservative. • Consider potential charging of the alumina ceramic inside the combiner magnet.

6. The quality of the vacuum system design, in particular: • The general design of the chambers for XHV. • The element of risk by the fabrication of the gun using multiple commercial vendors, imposed by the restrictions on in-house staff. • Potential failure points due to in-vacuum motion elements. • Consider the design for obtaining, maintaining and reading XHV reliably.

7. Laser and optical design • The issues of setup and alignment of twenty separate lasers onto twenty separate photocathodes. • Consider the optical windows, such as issues of birefringence. • Consider halo generation from stray light. • Consider the issues associated with delivering beam pulses with identical bunch charge from 20 cathodes.

8. Other issues. • Consider potential issues with the “C” magnets used to deflect the beam, such as astigmatic focusing. • Consider the phased plan of the experiment and the proposed schedule. • Beam instrumentation • Beam dump • Each talk will provide information on open issues and potential trouble spots

9. Review Agenda Gatling Gun Program Review, June 28th-29th, 2012 Start Time TopicsSpeakers 9:30 Introduction to the Gatling Gun Development Program J.Skaritka 10:00 Experience with GaAs Cathodes at BNL T. Rao 10:20 Polarized GaAs Cathode development and preparation of Gatling Gun Cathodes E. Riehn 10:40Break 11:00 Electro-Static Modeling Q. Wu 11:30 Beam Physics Modeling and Combiner design E. Wang 12:00Lunch (served in this room) 1:00 Tour of Cathode Preparation Lab Bldg. 966 E. Riehn 1:30 Vacuum system development and status J. Skaritka 2:10 Laser System development and status B. Sheehy 2:30 Break 2:50 Beam Diagnostics and Instrumentation D. Gassner 3:10 Depressed Collector and High Voltage system S. Pikin 3:30Outside component manufactures and status J. Skaritka

10. Welcome and thanks Welcome to the committee members – we appreciate your help! Thanks for the team working on the Gatling Gun!