# Presentation: 212280

## RHIC APEX & LARP

- Vladimir Shiltsev
*FNAL/APD*

## RHIC high L(polarized) hadron collider

**Operated modes (beam energies):**
- Au–Au  	10, 28, 31, 65, _100_ GeV/n
- d–Au*       	_100_ GeV/n
- Cu–Cu	11, 31, _100_ GeV/n
- p–p 	11, 31, _100_, 205, 250 GeV
**Possible future modes:**
- Au – Au	2.5 GeV/n (AGS, SPS 	c.m. energy)
- p – Au*	100 GeV/n  (*asymmetric rigidity)

**Achieved peak luminosities (100 GeV, nucl.-nucl.):**
- Au–Au  		 	  581030 cm-2 s -1
- p–p 			  351030 cm-2 s -1
**Other large hadron colliders (scaled to 100 GeV):**
- Tevatron (p – pbar)	  231030 cm-2 s -1
- LHC (p – p, design)	1401030 cm-2 s -1

- APEX Mtg 11/02/2006 - Shiltsev

## Performance limitations with partial to-do list

- Intra-beam scattering (heavy ions)
- Low dispersion lattice
- Stochastic (in progress) and electron cooling at 100 GeV/n
- Dynamic pressure rise from electron clouds
- NEG coating of warm sections 
- Pre-pumping of cold sections 
- Instabilities (at transition)
- Adjust chromaticity (chromaticity jump?)
- Reduce electron clouds
- Fast transverse damper
- Beam-beam (light ions and protons)
- Eliminate ~10 Hz orbit oscillation (in progress)
- Non-linear chromaticity correction (in progress)
- New working point ?
- Electron lens ??
- Polarization (protons)
- AGS: strong partial snake 
- AGS: horizontal tune in spin tune gap (in progress)
- RHIC: 100 GeV: 
- RHIC: 250 GeV: ring alignment, orbit correction

- APEX Mtg 11/02/2006 - Shiltsev

## Run-7 (President Budget request) (Q3)

**30 weeks of cryo operation**

- 1 1⁄2 week cool down 80K to 4K

- 3 week set-up/ramp-up A-A

- 1⁄2 week warm-up

- 10 weeks p-p physics

- 3 weeks set-up/ramp-up p-p

- 12 weeks of A-A physics

- Over last five years reduced cool-down/warm-up from 5 weeks to 2 weeks and reduced set-up/ramp-up from 2x5 weeks to 2x3 weeks  total reduction of operations overhead from 15 weeks to 8 weeks per year!
- LN2 cooler, He refrigerator improvements
- Automation, beam-based feed-back

- APEX Mtg 11/02/2006 - Shiltsev

## Goals for RHIC Enhanced Design Performance (~2008*) (Q4)

- * First 250 GeV p-p physics run currently scheduled for 2009.

- APEX Mtg 11/02/2006 - Shiltsev

## Schottky being baked, will go into LHC tunnel
TCFB: success at SPS
4 long-term hardware commissioners @CERN
SLAC joins commissioning forces
LHC@FNAL to open in Nov’07, new - LAFS
RC work at full speed, a lot of changes, delay
SPS beam studies: BBQ PLL, Q’ head-tail, bent crystal, etc
Wires built for RHIC tests
# of LARP presentations at Valencia workshop

- Schottky being baked, will go into LHC tunnel
- TCFB: success at SPS
- 4 long-term hardware commissioners @CERN
- SLAC joins commissioning forces
- LHC@FNAL to open in Nov’07, new - LAFS
- RC work at full speed, a lot of changes, delay
- SPS beam studies: BBQ PLL, Q’ head-tail, bent crystal, etc
- Wires built for RHIC tests
- # of LARP presentations at Valencia workshop

- APEX Mtg 11/02/2006 - Shiltsev

## Accelerator Systems FY07 Priorities

- Lumi-Monitors: build,install, start commissioning, _***RHIC test***_
_***Tune&Coupling FB: deliver design, participate in installation and commissioning***_
- Schottky: participate in installation and commissioning
- Hardware Commissioning: execute current plan – SAFELY!
- Beam Commissioning: develop acceptable/detailed execution plan for FY08+ by mid-07 _***(more from BNL!) – Todd, Mei***_
- Physics experiments: _***RHIC (BBLR),***_ Tevatron(PLL), ecloud
- Other tasks: execute Task Sheet’s Plans

- APEX Mtg 11/02/2006 - Shiltsev

## RHIC BBLR wires – assembly

- APEX Mtg 11/02/2006 - Shiltsev

## Planned test with RHIC BBLR wires (WF)

- Better signal from LR interaction(include head-on BB as another nonlinearity, larger chromaticity)
- RHIC BBLR wire commissioning(may be partially parasitic to operation, may improve collimation)
- Use wires to simulate LHC-like conditions(wires designed for LHC strength, beam lifetime better than in SPS tests)
- Test compensation of single LR interaction (in presence of head-on collision, need protons)
- Test pulsed power supply [not in 2007](confirm that beam lifetime is not negatively affected)

- APEX Mtg 11/02/2006 - Shiltsev

## Lumi-Mon Noise w. and w/o beam (Angelika D) 0.1mV 100mV

- no beam

- beam, 1 rev.

- APEX Mtg 11/02/2006 - Shiltsev

## Noise Problem (w. beam)

- 5 MHz/div

- 20 db/div

- 9.5 MHz      19 MHz    28 MHz                   46 MHz

- APEX Mtg 11/02/2006 - Shiltsev

## ???

- APEX Mtg 11/02/2006 - Shiltsev

## Estimate of SyncRad Suppression effect (WF)

- [H. Burkhardt, CERN]

- Energy loss from synchrotron radiation ~ Z2,makes heavy ions in RHIC particularly interesting

- APEX Mtg 11/02/2006 - Shiltsev

## AGS “Cooling” (Mike Bl)

- In the mid 90s Willem Van Asselt observed a narrowing of the IPM profiles with gold beams over the AGS injection porch.  The time scale was of order one second and the data were seen by several people.
- In 1995 K. Kilian  published a paper suggesting that collisional excitation of electronic states could cool beams.
- A very cursory AGS study in 2005 showed no emittance reduction.
- Theory has been pessimistic. C-A/AP/230

- IPM neutralization??; IBS ??

- APEX Mtg 11/02/2006 - Shiltsev