# Presentation: 802344

## RHIC Machine Status and Plans

- 	Brief summary of RHIC RUN2001/2
- 	Plans and goals for RUN2003 / RUN2004

## “Typical Au Store” # 1812

- Beam currents [x106 ions]

- Collision rate [Hz]

- Specific luminosity [Hz/1018]

## Integrated Au-Au luminosity

- FY2000
- (66 GeV/amu)

- FY2001 – 02
- 100 GeV/amu

- PHENIX during last 10 days:
- 24 (b)-1/week
- Lave(week) = 0.4  1026 cm-2 s-1
- Lave(week)/Lave(store) = 27 %

## RHIC R&D Challenges and Developments

- Intensity limitation for gold due to vacuum break-down (HI)
- Single- and multi-bunch instabilities (HI & PP)
- Tune feedback (PLL) (HI & PP)
- “Flat” orbits to avoid depolarization (PP)
- Intra-Beam Scattering (IBS) (HI)
- Determines RHIC Au performance
- Eventually will need electron cooling (see below)

## Vacuum break-down

- Only in warm sections that didn’t have bake-out; worse with 110 bunches/ring
- Ion desorption, electron desorption, electron multi-pacting, electron cloud?
- Installed electron detectors in IP12 and IP2 and solenoids for electron suppression in IP12.
- Vacuum bake-out of most warm sections; plan for “scrubbing” with beam

- 10-5 Torr

- Pressure at IP12
- Slow rise.
- Electron desorption?

- 55 bunches
- 9x108 Au/bunch

- Pressure at IP12
- Run-away rise
- Loss induced?

- 2x10-4 Torr

- 55 bunches
- 6x108 Au/bunch

## Transverse instabilities in RHIC

- Tomographic reconstruction of 2D bunch density

- Fast transverse instability (~ GHz)
- High sensitivity around transition
- Effect of broadband impedance, electron cloud (?)
- Cures: beam-beam tune spread, **octupoles, **transverse dampers, ...

- After instability with ~ 10 ms growth rate

- Before instability

## “Typical Proton Store” # 2304

- Beam currents [ 106 ions]

- Collision rate [Hz]
- Vernier scans:
- STAR: 104  0.6  1030 cm-2 s-1
- PHENIX: 104  1.6  1030 cm-2 s-1

- STAR

- PHENIX

## Integrated p - p luminosity

**Integrated p - p luminosity**

- STAR during last 20 days:
- 290 (nb)-1/week
- Lave(week) = 0.5  1030 cm-2 s-1
- Lave(week)/Lave(store) = 42 %

## RHIC Beam Polarization

- Measured Asymmetry

- Beam Intensity [x1011]

## Proton polarization at the AGS

**Proton polarization at the AGS**

- Full spin flip at all imperfection resonances using partial Siberian snake
- Full spin flip at strong intrinsic resonances using rf dipole
- Remaining polarization loss from coupling and weak intrinsic resonances
- Larger polarization loss in FY2002 due to lower ramp-rate motor-generator
- With high ramp rate MG, higher source polarization, and new AGS pC polarimeter expect more than 50 % AGS polarization
- To avoid all depolarization in AGS build strong AGS helical Siberian snake! (Installation in 2004)

## HERA and LEP luminosity evolutions

## RUN2003 Goals (~ 3-4 weeks into run)

- Prepare for four modes; all with:Energy/beam: 100 GeV/nucl., diamond length:  = 20 cm, Lave(week)/Lave(store) = 40 %

| Mode | # bunches | Ions/bunch [9] | *[m] | Emittance
[m] | Lpeak [cm-2s-1] | Lave(store)[cm-2s-1] | Lave (week)[week-1] |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Au-Au | 56 | 1 | 1 | 15-40 | 141026 | 31026 | 70 (b)-1 |
| (p-p)* | 112 | 100 | 1 | 25 | 161030 | 101030 | 2.8(pb)-1 |
| d-Au | 56 | 80(d), 1(Au)  | 2 | 20 | 41028 | 1.61028 | 4 (nb)-1 |
| Si-Si | 56 | 7 | 1 | 20 | 51028 | 21028 | 5 (nb)-1 |

-   * Beam polarization  50 %; Acceleration test to 250 GeV
- New hardware installed and to be commissioned:
- All eight spin rotators for PHENIX and STAR

## RUN2003 Integrated Luminosity Estimate

- Estimate for integrated luminosity for 29 week FY2003 run (starting October 1, 2002):
- 4 weeks cool down, 1 week warm-up, 2 weeks setup (for each mode), 3 weeks ramp up (for each mode): 
-    29 weeks of cryo ops.: 	d-Au:  	11 weeks at “final” luminosity
- 		p-p: 	3 weeks at “final” luminosity
- Minimum:  performance at end of FY2001/02 run
- Maximum: luminosities from previous slide

| 
Mode | Lave (week)[week-1] | Int. Lumi.
 | Lave (week)[week-1] | Int. Lumi.
 |
| --- | --- | --- | --- | --- |
| (p-p) | 0.3(pb)-1 | 0.9(pb)-1 | 2.8(pb)-1 | 8.4(pb)-1 |
| d-Au | ? | ? | 4 (nb)-1 | 44 (nb)-1 |

## RUN2004 Tentative Runplan

- For 29 week FY2004 run:
- 2 weeks cool down, 1 week warm-up, 2 weeks setup (for each mode), 3 weeks ramp up (for each mode): 
-    29 weeks of cryo ops.: 	Au - Au: 	12(11) weeks at “final” luminosity
- 		p - p: 	4(3) weeks at “final” luminosity