# Presentation: 922717

## Collider Run II - Doing Shots

- Elvin Harms
- Fermilab Antiproton Source
- _[Harms@fnal.gov](mailto:Harms@fnal.gov)__   X4387_

## What’s a Shot?

- Transferring Antiprotons from the Accumulator to the Tevatron.

## What’s Shot set up ?

- All of the preparatory steps needed to do shots.

## Accelerator Complex Overview

**Tevatron**

**Proton source**

**Main Injector**
**Recycler**

**Antiproton source**

## Accelerator Complex Overview

**Tevatron**

**Proton source**

**Main Injector**
**Recycler**

**Antiproton source**

- AP3

- P2

- P1

- AP1

- A1

- MI-8

## Shot set-up – prerequisites

- Previous Store ended
- Tevatron at 150 GeV (fringe fields on P1 & P2)
- Desired number of antiprotons accumulated

## Shot set-up – a 3-ring circus

*Shot set-up – a 3-ring circus*

| Tevatron | Main Injector | Pbar source |
| --- | --- | --- |
| Set at 150 GeV | Check/correct closed orbit | Cool Pbars into core & maintain stability |
| Verify/correct A150 line tune | Check/correct extraction positions | Accept reverse protons, maximize transmission from MI, minimize injection oscillations |
| Load protons | Provide protons for tuneup of beam lines | Redistribute core longitudinally for unstacking |

## Shot set-up – Pbar basic steps

- Stop stacking
- Cool core
- Tune up P1, P2, AP1, AP3 at 8 GeV with Reverse protons
- Minimize betatron oscillations in Accumulator
- Redistribute core
- Unstack and extract 4 bunches nine times
- Return to stacking

## Shot set-up – Sequencer

- 6 aggregates
- Promotes reproducibility
- Automates much of process
- Flexible
- ‘Pbar Back-up’ for now

## Shot set-up – Antiproton source tools

- Core cooling
- RF systems
- ARF1, h = 84, – matching to MI
- ARF2, h = 2, – stability, squaring
- ARF4, h = 4, – unstacking

## Sequencer – Start Shot Set Up

- arm SDA
- set up alarms
- AP1 from 120 to 8 GeV
- AP3 on
- Reverse proton TLG
- Prompts for MI,P1 -> AP3 tune up
- maintain core stability
- tranverse emittances
- longitudinally

## Start Shot set-up

- Reverse Proton tune up – P143
- User-friendly version being developed

## Start Shot set-up

- Minimize Accumulator Turn-by-Turn oscillations – P140

## Sequencer – Set Up...

- TLG for Pbars loaded
- 4-8 GHz core momentum cooling on
- cw ARF2 on
- A:EKIK timing for pbars

## Sequencer – ‘Dry’ Shots

- Test shots without beam
- RF systems play except for unstacking amplitude
- Verify phase lock
- Verify timing
- Verify kicker magnets are working

## Sequencer – Square Core...

- Set up ARF2 to shake the core
- Frequency-modulated 1.25 MHz RF – set interactively
- Unstack uniform intensity bunches

## Squaring the Core

- ‘square’ core allows uniform intensity of pbar bunches

## Sequencer – Run II Unstacking...

- Cooling off
- Shutters open
- ARF4 set for to unstack
- Clock events enabled/disabled for transfer
- Unstack/transfer to MI
- Cooling back on and wait

## Unstacking Timing

- TCLK $91 to unstack
- TCLK $9A prepare to transfer
- MIBS $7A (plus delay) to transfer

## Unstacking

- 2.5 MHz (h=4) RF system – ARF4
- 4 bunches at a time
- low initial voltage
- increase voltage to narrow bunches
-  lock to MI RF
- bunch at 53 MHz (h=84)
- extract
- ~30 seconds per transfer

## Unstacking & Extraction

- Re-bunch at 53 MHz on extraction orbit
- Shuttered fast kicker magnet (1.6s)

## Doing Shots

- Transfer to MI
- Acceleration to 150 GeV
- coalescing

## Doing Shots

- Coalescing
- 4-53 MHz bunch _trains_ into 4-2.5 MHz _bunches_

## Sequencer - Return to Stacking

- Close out SDA
- Re-cool beam into core
- Set up alarms for stacking
- Timing reset for stacking
- AP3 off
- AP1 set to 120 GeV
- RF systems and diagnostics reset for stacking

## Important Tools

- Sequencer
- Time Line Generator (TLG)
- Dedicated Applications
- CDA/SDA

## Unique Applications

- P140 – VSA TBT
- P142 – VSA Acc Long Prof
- P143 – APX. Lattice (Beam line tuner)
- P185 – Emittance Calc
- P186 – AP0 Scope

## Important Tools

- Sequencer
- ACNET application
- Automates much of the process
- Flexible
- Interactive

## Important Tools

- Time Line Generator (TLG)
- central Beam switching system
- who gets what beam when and how often
- different Timelines for different modes
- Shot set up
- Load protons
- Load pbars

## Important Tools

- Dedicated Applications
- Beam line tuning
- Orbit display and control
- RF and stochastic cooling systems
- Diagnostic display
- Parameter pages

## Important Tools

- CDA/SDA
- Gather, display, and analyze data from shots
- State-based
- Java applications

## Armchair Shooter

- How to watch?
- Channel 13/Notify
- Pbar TV channel 7 – AP1 wall current monitor
- Pbar TV channel 15 – Accumulator Vector Signal Analyzer
- Pbar TV channel 16 – Accumulator unstacking display
- Pbar TV channel 18 – Accumulator Vector Signal Analyzer
- Pbar TV channel 28 – Accumulator Stack (longitudinal) Profile

## Summary

- Tools are in place for Run II operation
- Refinement still in progress
- We’re still learning how to do shots
- Work with us!