# Presentation: 143746

## Status of the AP2 Optics

- Keith Gollwitzer
- Antiproton Source Department
- November 19, 2004

## Purpose & Use of AP2

- Transport of pbars from target-lens to Debuncher
- Goal of transporting of 35 mm-mrad (norm. 330 mm-mrad) & P/P of ± 2.25%
- Many secondaries come out of the target and enter AP2
- Number of pbars for Run 2 is ~1e8 per stacking cycle
- ~1% of secondaries at the end of AP2 are the desired pbars

## 5 Year History of AP2 Optic Models

- Fermilab MAD for Console Application for beam line orbit corrections (1999)
- Verification(?) when part of forward proton study of complete P1-P2-AP1-AP2 beam line
- Fermilab OptiM offline studies (2001-now)
- Includes apertures and has been compared to older survey
- LBNL MAD studies (2003-2004)
- Alignment and chromatic effects on transport efficiency
- LBNL AT [Accelerator Toolbox] (2004)
- Continuation of MAD studies and includes turns in Debuncher (in progress)

- Will not   Cover today

- There have been no lattice meas.
-  to verify these models

## Current Lattice Functions

- Target Station & Lens

- Left Bend

- Down Bend

- Injection

## What to do about Lattice

- Previous slide showed an asymmetric lattice about the left bend including large horizontal 
- This shutdown some rework of powering AP2 quads
- Q724 will be powered (new supply)
- Q725 moved from Q716 buss to own supply
- Q702&703 shunts swapped with Q719&720
- Q728 shunt swapped with Q732
- Change to new lattice after startup

## Proposed Lattice Functions

- Target Station & Lens

- Left Bend

- Down Bend

- Injection

## Beam Sizes for All of AP2

## Beam Sizes for Upstream AP2

- Dump & Shielding

*Perfect Alignment*

- New Beam Stop

## Beam Sizes for Left Bend of AP2

## Beam Sizes for Downstream AP2

- IBV1 V730

- Injection Septum

## A Look at Tracking

- MARS simulation to generate pbars from 120GeV protons striking the target
- Since momentum spectrum is flat, can re-use particles by randomizing momentum
- OptiM does the Lithium lens focusing and multiple scattering as well as propagation and checking against apertures
- Tracking has been used to confirm “loss points” as well as optimize transport efficiency

## Intensity and Momentum Spread while being tracked through AP2

- MARS simulation of 120GeV protons on target
- & production of pbar secondaries
- Tracking by OptiM
- Initial beam spread of ±15%

## AP2 Chromaticity

- Valeri performed studies a few years ago for Run 2 Upgrade Plan and a quick look recently
- Originally optimize for current power circuits; now have plan with minimal changes noted before
- Noticed chromatic effect that appears to decrease transport efficiency by ~10%
- Believe can recover half of the losses(?)
- LBNL is studying and we will in the near future

## Big symbols are where the set of different momenta particles started out of Lens

- +2% pbars

- {x,y} position coming out of Lens, no angle

- Small symbols is position distribution coming out of Injection Septum in Debuncher

## Ideal to add sextuple in dispersion regions
                          No space

Alternative is to add sextuple component to existing quadruples
Modeling in progress
Power each half of quad separately
Beside sextuple will also have dipole kick
Will have to rotate quads in horizontal dispersion regions

- Ideal to add sextuple in dispersion regions
-                           No space
- Alternative is to add sextuple component to existing quadruples
- Modeling in progress
- Power each half of quad separately
- Beside sextuple will also have dipole kick
- Will have to rotate quads in horizontal dispersion regions

- Chromatic Solution(?)

## Status

- Repository has OptiM August04 lattice
- Need to update apertures
- Need to update circuits
- Change excitation once new lattice is applied
- Compare laser tracker component positioning with model once survey data are available
- Verify models with lattice measurements
- New BPM system to be available in the next few months