# Presentation: 123938

## Beam Experiments: Spin-Off

*Fulvia Pilat*

## Beam Experiments: spin-off

- Outline
- Beam experiments programdefine spin-off
- Time, planned, scheduled, available
-     Run 03 and 04
- Spin-off Run 01 and 03
- Spin-off Run 04

## Program goals

**Beam Experiments GOALS**
- Improve machine **performance** (_longer time scale than ‘now’_ machine performance)
**Upgrade** programs (RHIC-II, e-cooling, e-RHIC)
- Development of_ _beam **diagnostics** **techniques**
- Inter-lab **collaborations** (common goals, exploit synergies, exchange personnel, etc.)
**SPIN-OFF**:only  _beam experiments____operations_

## Beam Experiment time - Run 03

| period | Planned
 (h) | Scheduled
 (h) | Beam available (h) |
| --- | --- | --- | --- |
| first 5 weeks | 60 | 36 | 24 |
| d-Au run
(10 weeks) | 120 | 100 | 65 |
| pp run | 36 | 26 | 20 |
| total run 2003 | 156 | 126 | 85 |

- Scheduled/planned		~80 %
- Beam/planned		~55 %
- Beam/scheduled		**~65%**

## Beam Experiment time - Run 04

| period | Planned
 (h) | Scheduled
 (h) | Beam available* (h) |
| --- | --- | --- | --- |
| Au-Au run
(13 weeks) | 156 | 141 | 119 |
| pp development | 0 | 12 (last shift) |  |

- Scheduled/planned 	Au	~90 %
- Beam/planned		Au	~76 %
- Beam/scheduled	Au	**~84%**

- *Ignored beam
-  interruptions < **1⁄2 hour**
-  **Overestimates availability**

- Impact of other programs (pp setup, NSRL)
- Beam/scheduled during NSRL setup:	         65%
- Beam/scheduled last 3 beam-ex sessions:      80%

- Overall improvement of beam experiments productivity from
- last year – reflecting overall  **increase of machine performance/reliability**
- and _**people experience/creativity**_

## Spin-off Run 01 and 03

**Operational IR correction:**
- 	skew quadrupole (IR coupling), sextupole
**Chromaticity** measurement on the ramp
- 	 radial wiggle+PLL
**Octupoles** around transition
**PLL**, feedback, high resolution tuning
**Tune scans** in collision  working points

## Spin-off Run 04 - operations

**IR corrections** (across IR, sextupole, octupole)
**Tune scans** (store, injection)  working point
-     						(*talk Rogelio Tomas*)
**AC dipole**, optics measurements (coupling in progress)
- Pressure rise  confirm **NEG pipes**, **solenoids**
- 						(*talk Vadim Ptitsyn*)
**Beta* squeeze**  beta*=85-90cm in Phenix, Star
***Decoupling ****via skew modulation**	*(*talk Yun Luo*)

## Operational IR correction - summary

| Sextupole
corrector | Strength *=2m
5000 A   
Run2003  d-Au | Strength *=1m
2000 A  
Run2003   pp | Strength *=1m
2000 A
 Run2004   pp | Strength *=1m
5000 A
Run2004 Au-Au |
| --- | --- | --- | --- | --- |
| yo5-sx3 V | -0.014 | -0.003 | -0.001 | -0.006 |
| yi6-sx3  H |  0.004 |  0 | +0.001 |  0.003 |
| yi7-sx3  H
yi7-oct3 |  0.003 |  0.007 | +0.001 | 0.0005
-0.05 |
| yo8-sx3  V
yo8-oct3 | -0.01 | -0.038 | -0.0012 | 0
-0.1 |
| bi5-sx3  H |  0.0012 |  0.001 | -0.0022 | 0.0011 |
| bo6-sx3  V | -0.004 | -0.003 | 0.001 | -0.001 |
| bo7-sx3  V |  0.0 | -0.003 | -0.007 | 0 |
| bi8-sx3  H |  0.0 | -0.0005 | +0.002 | 0 |

## Operational IR correction 2004 

- Dec./January (ops Au-Au)	YIR6: sextupole
- 				YIR8, BIR6, BIR8: Oct at triplets + sex across IR			blue and yellow IR8: (strong octupoles)
- January 20 (beam ex)	dynamic aperture yellow
- 				DA without IR corr > DA with IR correction
- January 25 (ops Au-Au)	check lifetime – undo yellow IR8 correction
- January 27 (beam ex) 	re-do yellow IR8 correction (sex+oct)
- 				with bumps across IR (weak octupoles)
- February 3 (beam ex)	re-do blue IR6 correction
- 				with bumps across IR’s  (weak octupoles)
- February 11 (beam ex)	measure dynamic blue
- 				DA with IR corr > DA without IR corr
- March 22 (beam ex)	measure dynamic aperture yellow
- 				DA with IR corr > DA without IR corr
- April 17 (ops PP)		correction blue, yellow – sextupole
- May 14  (last shift)	dynamic aperture – blue and yellow
- 				(with IR correction only)

- _Beam ex-parasitic_

## January 20: dynamic aperture (yellow) 

- IR correctors on

- IR correctors off

- IR sext off

- IR oct8 off

- IR oct7 off

- January 20: dynamic aperture (yellow)

## February 6. Re-correction IR6

- Procedure:
- Fix orbit, separate tunes, check lifetime
- Bumps across IR correction
- Re-check lifetime, re-set tunes, orbits in IR’s

## Re-correction IR6 – linear and quadratic fit

- hor sextupole

- ver sextupole

- hor octupole

- ver octupole

- Before correction

- after correction

## February 11: DA - blue

- Tunes: 0.232, 0.229 (operations)

**IR corrections OFF**

**IR corrections**
**ON**

**IR corrections OFF**
**strong octupole**
**bo7-oct2=0.4 (~20A)**

## March 22: DA - yellow

- Vertical kicks

- IR correction ON
- Collisions OFF
- bucket 61

- IR correction OFF
- Collisions OFF
- bucket 121

- Normalized emittance

- IR correction on
- Collisions ON
- bucket 181

## Beta squeeze

- Beta* knobs (cfr. Walter Wittmer seminar/work) : vary beta* at IP without developing a new ramp. range: 10-20% (perturbation to existing solution)
- Re-matching (Van Zejits, Wittmer) with **on-line model** necessary
- _Motivation_:
- LHC:
- Extend to LHC lattice (anti-symmetric) the beta* tuning capability used in LEP (symmetric optics)
- _Continuous beta squeeze during the store for lead-ion option_
- RHIC:
- Explore operational feasibility of beta*<1m  development of ramp with beta* < 1m  for next run(s) beta squeeze with e-cooling?
- February 25:	 measurement of beta*, tests
- March 2: 	12% squeeze Phenix (blue&yellow)
- March 11: 	14% squeeze Phenix and Star (blue only....)
- March 16:	12% squeeze Phenix and Star (blue and yellow)

- (Wittmer, Van Zejits, Pilat)

## Beta squeeze in Phenix only

- 56x56 store

- Steering
- In IP8 and IP6

- Beta* squeeze
- In IP8 by 12%

- Re-steering
- In IP8 and IP6

## Beta* squeeze Phenix only

- Background – no collimation

- Beam decay

- rates

## Rates - tunes

## Beta* squeeze – Phenix and Star

**PROCEDURE:**
- Ramp 45x45 – normal physics conditions
- Steering, collimationSTAR and PHENIX data taking ~10-15 min
- Take collimator out
- Squeeze **12%**  (both beams)
- Fix lifetime
-     (yellow0.003 retuning, bluedecoupling+tune fix)
- Auto-steering, collimation
-       STAR and PHENIX data taking (STAR TPC included)

## overview

- Retract
- collimators

- collimation

- steering

- Fix yellow
- lifetime

- Fix blue
- lifetime

## Slide 21

## Quick Look at Beam Experiment to Decrease * from 1 to ~ .88

- Quick Look at Beam Experiment to Decrease * from 1 to ~ .88
- March 17, 2004  *B. Christie for STAR*

- Red = ZDC East
- Green = ZDC West
- Blue = ZDC Coin.

- ZDCs

- ZDCs

- Red = BBC East
- Green = BBC West
- Blue = BBC Coin.
- Purple = Yellow back.
- Pea grn = Blue back.

- BBCs

- BBCs

- Time of Day

- Rate (Hz)

- Time of Day

- Rate (Hz)

## Beta squeeze < 1m for Run 05 ?

- For LI-LI and PP _default is 1m (projections based on this)_
- Online matching (Johannes) over the summer to investigate solution with beta*=85-90cm
- Main issues:
- _Dispersion matching_
- _PS currents (leads)_
- If successful, option for LI-LI Run 05
- Investigate PS work necessary for beta*<0.85m
- Motivation:
- Luminosity
- Beam experiments
- Dynamic beta* squeeze on the ramp ( low transverse emittance with electro cooling....)

## Other results Run 04 (talk Vadim Ptitsyn)

- Pressure rise, measure of **desorption** coefficients
**Dynamic aperture**, blue and yellow, Au,pp, in and off collision
**IBS measurements**, gaussian and hollow beam
**Transverse echo**
- Measurement and partial correction of **non-linear chromaticity**
**......****.**

## Beam Ex Operations (Run 05)

- Coupling correction via **skew quad modulation**
**AC dipole – coupling** measurements, correction
**Schottky development** for _chromaticity_, _emittance_ and _tune spread_ measurement
**Driving terms**, non-linear
- Operational **IR correction, skew sextupole ?**

- Yellow IR8
- Vertical bump 5mm
- Skew sextupole