# Presentation: 371587

## Beam Based Determination of Limiting Apertures in the Debuncher

- Vladimir Nagaslaev
- Keith Gollwitzer
- June 10, 2004

## AP2 & Debuncher Aperture Upgrade Outline

- Goal of Upgrade
- Projects
- Modifications
- Orbit Control
- Beam Based Alignment
- Determination of next aperture (Vladimir)
- Comments & Progress

## Goal: Lots of Pbars to Circulate in Deb.

- < 20 mm-mrad
- 20-40 mm-mrad
- > 40 mm-mrad

- Simulation of pbar transverse phase space (both planes) out of a 750 T/m lens.
- {2 entries for each pbar that traverses only Lithium part of lens}
* *
- Collect as much as possible for Debuncher Cooling Systems

-  *35**** mm-mrad aperture allows 320**** mm-mrad beam emittance*

## Known Restrictions

**Band 4 cooling tanks arrays**
**	**Vertical array gaps were designed for ~30 mm-mrad
- 		Determined that increasing the gap by 3.1mm can be done.
- 			Will decrease frequencies of upper band of system to
- 			overlap with lower band; _not_ affect overall cooling.**  **
**Move DRF2 & DRF3 to low/zero disp. region(s)**** **
**	**** **Radiation surveys show activation
- 		-DRF3 has been re-located to low dispersion.
- 		-Looking into different schemes of where to
- 		  re-locate DRF2 and essential electronics.
**Other restrictions**
**	***Identification and solutions may have to wait for modeling, beam studies and/or mitigation of other restrictions.*
**	**Identified that the extraction kicker’s elliptical pipe is 22 mm-mrad aperture for off momentum particles.
**	****	**Appears that inserting a rectangular beam pipe will
- 		be sufficient.

- 2005

-     2003
-   2004

- 2005

## Debuncher Extraction Kicker

**Upstream End** – Beam Profile First Turn in Debuncher– **Downstream End**
- 82% of tracked beam particles inside of current beam pipe (ellipse).
- Rectangle of same inner dimensions accepts 91%.
- Increase horizontal dimension will accept 95%: Looking into offsetting pipe in kicker, but beam fairly small when extracting (good field region?)
- Will also motorize kicker stand to center beam pipe about beam.

## Limiting Apertures

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

## Steering Restrictions

**Motorize stands for septum & kickers**
- 	 Tolerances are small; desire to center devices
- 		Engineering will start by looking at existing
- 		tank motorized stands.
**Injection septum (common vacuum chamber)**
- 	 Desire injected beam to be close to closed orbit
- 		Investigating whether spare can be reworked
- 		to minimize material at down stream end.
**	**
**D4Q4 replacement & BPM removal/relocation**
- 	~No vertical tolerance for injected beam
- 		2 large spare quad LQBs will replace quad;
- 		same integrated field and fits into space.
- 		Need stand work;  have existing power supply.

-  2004
- & 2005

- 2004

- 2004

##      D4Q4 Aperture         

-      D4Q4 Aperture

- No tolerance for injected beam.
- Will replace with two **large quad LQBs (pole tips drawn)**;
- increase vacuum chamber.
- Move BPM from upstream area.

## Top Set: Trims in the year 2000Middle Set: Trims & Motorized Quad Stands in 2001Bottom Set:  Trims & Motorized Quad Stands nowWill add more Motorized Quad stands in next shutdown

- Vertical                        Horizontal

- Debuncher Orbit Control

## Operational Comments

- Debuncher normal operations
- Initial beam
- 1010 secondaries
- Secondaries decaying
- 53MHz immediately de-bunched
- Final beam (<2seconds)
- 108 “cooled” antiprotons
- Beam de-bunched
- Debuncher Study conditions
- Reverse protons
- Up to 1011 protons
- < 1010 captured by study RF system

## Horizontal

- Vertical

- Start Beam Based
- Determination of
- Limiting Aperture

- Running Wave

- Debuncher Only – Reverse Protons

## Next: Vladimir

## What the Simulations Suggests?

## Realization of 35 mm-mrad

- 	Identify & Understand Restrictions
- 		Documentation Research
- 		Optical Survey
- 		Lattice Modeling
- 			LBNL study of AP2 chromaticity
- 		Instrumentation
- 		Beam Studies
- 	Mitigate
- 		Redesign/modify/rebuild specific elements
- 		Align/relocate specific elements
- 	Beam Based Alignment
- 		Lattice Model
- 		Instrumentation
- 		Orbit control
- 		Beam Studies