# Presentation: 099902

## Antiproton Acceptance

- Steve Werkema
- February 8, 2005

## Goal

- Increase the number of antiprotons collected from the target _by_:
- 1) Increasing the admittance of the AP2 beamline and the Debuncher to **35 ******** mm-mrad**
- 2) Increasing the gradient of the collection lens to **100 kG/cm**

**Note:** Yield curves in model reduced by 10% to approximately account for chromatic effects

**1.5 ******

**Notes:**
Admittance corrections due to use of incorrect beta-functions for admittance calculations:
Horizontal admittances should be increased by 12%
Vertical admittances should be increased by 7%

## Progress So Far

## AP2 & Debuncher Acceptance

**†**** **	AP2 + Debuncher admittances reported at the Feb 2004 review were:
- 	 Horizontal: 24 	mm-mrad, Vertical: 18  mm-mrad

******* **Debuncher admittances reported at the Feb 2004 review were:
- 	 Horizontal: 28 	mm-mrad, Vertical: 20  mm-mrad

|  | Most Recent Measured AP2 + Debuncher | Most Recent Measured Debuncher | Max. Measured Admittance
AP2+Deb / Deb | Smallest Known Aperture | Goal |
| --- | --- | --- | --- | --- | --- |
| Horizontal 
(mm-mrad) | 24 ± 3 † | 24 ± 3  | 3033 | 36  | 35  |
| Vertical 
(mm-mrad) | 20 ± 2 † | 21 ± 2  | 2023 | 30  | 35  |
| Momentum | ±2.15% | ±2.30% | ±2.30% | -- | ±2.25% |

## The Plan 

**Identify Limiting Apertures**
- Assemble Documentation and Drawings (FNAL Tech. Div.) 	(WBS 26.2.2.1)
- Optical Survey and Alignment 	(WBS 26.2.2.2)
- Improve AP2 and Debuncher Lattice models 	(WBS 26.2.2.8)
- Beam based determination of limiting apertures 	(WBS 26.2.2.9.2)
**Mitigate aperture restrictions**
- Redesign/modify/rebuild/relocate beamline elements 	(WBS 26.2.2.5)
- DEX Bump
- Chromatic correction of the AP2 beamline (LBNL)	(WBS 26.2.2.7)
**Implement Beam Based Alignment**
- Instrumentation upgrades 	(WBS 26.2.2.3)
- AP2 BPMs
- Debuncher BPMs
- Orbit control 	(WBS 26.2.2.6)
- Install additional dipole trims in AP2
- Motorized quad stands in the Debuncher
- Beam Based Alignment 	(WBS 26.2.2.4)
- Develop procedures
- Software development
- Beam studies 	(WBS 26.2.2.9)

## Identification of limiting Apertures – Documentation, Survey

*** ******Documentation and Drawings***
- AP2 & Debuncher Physical Aperture tables complete. Apertures have been incorporated into the lattice models.
- Present activity consists of keeping these tables up-to-date
-  ***Optical Survey***
- Survey data collection completed during Fall 2004 shutdown
- Survey data analysis expected to be complete in March 2005

## Identification of limiting Apertures – Beam Based Methods

- Aperture Painting – Running Wave

## Identification of limiting Apertures – Beam Based Methods

- Bumping around the Debuncher
-  Center moveable devices on beam.
-  Build high precision Debuncher intensity monitor (D:BPI801).
-  Construct 3-bumps that cover the Debuncher (43 horiz. + 42 vert. bumps)
-  During stacking, move each bump 2 mm while  monitoring Debuncher intensity.

- Measured during Stacking

## Identification of limiting Apertures – Beam Based Methods

- Block diagram of intensity monitor 
_**Status**_:
-  Intensity monitor is operational
-  Procedure verified
-  1⁄2 of 3-bumps verified
-  Plan to enlist the assistance of operations crews to perform procedure.

## Mitigation of Limiting Apertures

- Debuncher injection region modifications
- Move DRF2
- Widen vertical band 4 stochastic cooling arrays
- Debuncher extraction kicker upgrade
- DEX Bump
- Chromatic correction of the AP2 beamline
- AP2 Beam stop

- Proposal complete by March 2005 (6 month delay)

- Removed/moved during Fall 2004 shutdown

- Est. completion: Spring 2005

**Extra**
**Credit**

## Mitigation of Limiting Apertures – Debuncher Injection Area

- Debuncher Injection Area Modifications:
- Injection septum common vacuum
- Replace D4Q4 SQC quadrupole with two LQB quadrupoles
- Motorize injection septum and kicker stands
- Vacuum system modifications
- Bigger D4Q4 vacuum chamber
- Move BPM upstream of D4Q4

## Mitigation of Limiting Apertures – Debuncher Injection Area

**Old Layout**

## Mitigation of Limiting Apertures – Debuncher Injection Area

**New Layout**

- Septum

- D4Q4a

- D4Q4b

## Mitigation of Limiting Apertures – Debuncher Injection Area

- D4Q5 configuration

## Mitigation of Limiting Apertures – Debuncher Injection Area

- Injection Septum Common Vacuum

## Mitigation of Limiting Apertures – Debuncher Injection Area

- D4Q4 Aperture

- Old

- New

_**Note**_: Injected and circulating beam are vertically separated here.

## Mitigation of Limiting Apertures – DEX Bump

- _D_ebuncher _Ex_traction Bump
**Purpose:** To rapidly move beam close to the extraction septum late in the stacking cycle (after it has cooled)
**Status:**
-  Two trim dipoles installed in Debuncher during the Fall 2004 shutdown
-  All cables to the tunnel have been pulled
-  Power supplies are being built by EE suppt. (est. completion: Feb. 2005)
-  Installation and testing of ramp controls (MDAT) (Feb. 2005)
-  Commissioning beam studies (March 2005)

## Mitigation of Limiting Apertures – Chromatic Correction

**Chromatic Correction of the AP2 Beamline**
- Work being done in collaboration with LBNL
-  Model chromatic effects
-  Beam studies to test model
-  Propose correction scheme (March 2005)

- AP2 line chromatic -functions

## Mitigation of Limiting Apertures – Chromatic Correction

- Normal Sextupole added to Q701, Q702, Q703, Q704; Q719, Q720
- Skew Sextupole added to Q731, Q733

**AP2 Chromatic Correction Scheme**

## Mitigation of Limiting Apertures – Chromatic Correction

- Setup for adding a variable sextupole component to a quadrupole magnet
- Separately powering the left and right halves (or rotating the arrangement shown here by 90o) produces normal sextupole.
- Separately powering the upper and lower halves produces a skew-sextupole (shown here ).

## Mitigation of Limiting Apertures – Chromatic Correction

- Measurements of integrated sextupole vs. average quadrupole excitation current for various differential excitation currents.

## Mitigation of Limiting Apertures – AP2 Beam Stop

- Mis-alignment of AP2 beam stop & beam pipe

## Mitigation of Limiting Apertures – AP2 Beam Stop

- Horizontal aperture after removal of AP2 beam stop

## Mitigation of Limiting Apertures – AP2 Beam Stop

- Yield to downstream end of AP2 line increased ~10% as a consequence of the removal of the AP2 beam stop.
_**Plans**_:
- Plan to install new beam stop downstream of Q704 during the Fall 2005 shutdown.

## Yet to be Corrected Limiting Apertures

*** **The numbers in this column were calculated using -functions at ***p/p* = 0

| Device | Horizontal |  | Vertical |
| --- | --- | --- | --- |
|  |  | * |  |
| Band 4 H pickup | 36.8  | 36.3  | 48.7  |
| Band 4 V pickup | 40.5  | 39.0  | 29.9  |
| Band 4 H kicker | 36.0  | 35.5  | 48.7  |
| Band 4 V kicker | 41.2  | 41.1  | 30.1  |
| Deb Extr. kicker | 109.1  | 21.9  | 35.8  |

- Central orbit (p/p = 0) limiting apertures:
- 	Horizontal:	36.0  mm-mrad
- 	Vertical:	29.9  mm-mrad
- Combined effect of Band 4 and Extr. Kicker upgrades once these admittances are achieved is ~7.4% (from particle tracking).

- Not to be
- changed

## Yet to be Corrected Limiting Apertures

- Vertical band 4 cooling pickup and kicker
- Upgrade arrays during Fall 2005 shutdown
- Likely requires 8 week shutdown
- Debuncher extraction kicker
- Presently evaluating the impact of the proposed aperture upgrade on field quality and load impedance.
- Go/no-go decision in February 2005 (this month)
- If this is a go, the upgrade will be installed during the Fall 2005 shutdown.

## Beam Based Alignment – Instrumentation

***Instrumentation***
- AP2 BPMs
- Deb. Extraction kicker noise issues resolved
- DAQ hardware & software upgrade –
- 		Est. completion: Mar. 2005
- Debuncher BPMs
- All 6 sectors installed and operational
- Console software is functional and in routine use
***Orbit Control***
- Debuncher motorized quad stands
- All motorized quad stands have been installed (completed during Fall 2004 shutdown)
- Bumps for <1/3 of the ring have been used so far for aperture optimization
- Position 3-bumps for 1/2 of the ring have been verified

## Beam Studies

- Studies since the February 2004 review
- Reverse proton studies
- Debuncher Orbit correction (in conjunction with running-wave aperture determination)
- Development of running wave aperture finding in the Debuncher
- AP2 BPM development studies
- Bump verification with new motorized quad stands
- Admittance measurement
- Stacking studies
- Measure AP2 + Debuncher admittance
- Development of AP2 BBA using Debuncher TBT
- Study chromatic effects (momentum slicing experiments)
-   bumps in AP2
- “Bump around” Debuncher – procedure development

## Beam Studies – How Beam Time was Spent

## Beam Studies – When we got the Time

## Beam Studies – Future Plans

- Reverse Proton Studies
- Verify Debuncher 3-bumps (6 hr)
- Align beam in Deb. injection channel (3 – 5 shifts)
- DEX bump studies (2 – 4 hr)
- Alignment of downstream end of AP2 line with new AP2 BPMs (3 – 4 shifts)
- Stacking Studies
- DEX bump commissioning
- Bump around Debuncher
- Beam based alignment of AP2 with new BPMs

## Lithium Lens Upgrade

- Spare Prototype 1 Lenses
- Building conventional spare first
- First Prototype 1 lens complete by ~6/1/2005
- New power supply for testing
- Russian power supply  more difficult than expected
- Increased support (K. Bourkland + A. Leveling)
- Expect completion ~6/2005
- Prototype 2 Lenses
- Delayed due to lead engineer (Pat Hurh) assuming role of Mech. Supp’t department head
- Diffusion bonding complete ~mid-March 2005
- Ready to fill ~late June 2005
- Ready to test ~ late August 2005 (~6 months of testing after that)
- New Lens Transformer
- Rejected vendor’s transformer due to faulty machining
- Expect completion by ~5/30/2005