# Presentation: 242715

## Week in Review: 1/06/03 -1/12/03

**  ****Ron Moore – FNAL**

- Store Summary
- Studies Highlights
- First Pbars from Recycler to Tevatron
- Strategy for Recovery from Shutdown

- All Experimenters' Mtg - 13 Jan 03

## Store Summary

| Store | Initial
Lumi | Deliv’d
Lumi | Termination | Comments |
| --- | --- | --- | --- | --- |
| 2146 | 22.5 | 747 | Quench | 1 bad pbar transfer; Proton length blow-up; 
A2 CC tripped off |
| 2150 | 28.5 | 104 | Quench |  1 bad pbar transfer; 
A3 VFC failure after 60 minutes |
| 2153 | 26.4 | 1197 | Intentional | Lost 1 pbar transfer, another was bad |
| 2155 | 29.7 | 1328 | Intentional | New MI RPOS switch – pbar transfers OK |

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Store #2146 Proton Length Blow-Up

- Longitudinal damper gain too high – caused proton bunch length blow-up
- At left, P35 after blow-up
- Should be Gaussian with 2.0 ns sigma

**20 ns**

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Slide 4

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Slide 5

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Slide 6

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## 1 Shift Access on Monday

- Tevatron – surveys for shutdown preparation
- As-found CDF low betas to be shielded
- Complete survey of “interesting” magnets in E-sector
- As-found where NuMI magnets are stored above Tev
- Main Injector
- Repair/check water leaks on RF 6, 9, 106 MHz cavity
- Find vacuum leak in 600 section – no time to repair
- Tours for shutdown preparation

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Tev Studies Summary

- Ramp proton bunches of various intensity/length
- Correlate loss up ramp with bunch length/shape
- Oscillating, non-Gaussian bunches lost 10%
- Stable, Gaussian-like bunches lost few %
- Aperture scans for comparison after shutdown
- Test several modified BPMs    (PSD boxes removed)
- Position signal somewhat better without PSDs
- Understand differences between coalesced/uncoalesced beam
- Goal: obtain reliable orbit data in HEP stores to control drifts
- Check effect of RF phase noise on bunch lengthening
- Opened RF phase feedback loops – obvious increases in growth rate and abort gap losses
- Understand this effect on DC beam growth in stores

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Example of “fairly Gaussian” 

- Example of “fairly Gaussian”
- proton bunch

- Example of a “not-so-Gaussian”
- proton bunch

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## % loss of protons up ramp 

- % loss of protons up ramp
- vs intensity

- % loss of protons up ramp
- vs “Gaussian sigma
- bunch length” @ 150 GeV

- Oscillating, not
- very Gaussian

- Small oscillations,
- more Gaussian

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Tev Studies Summary cont’d

- Tune scan with Tevatron Electron Lens
- Move tune of single bunch with e-beam
- Study beam lifetime versus tune
- Compare to new “gaussian” TEL gun after shutdown
- Flying wire – sync light emittance comparison
- Understand systematic differences
- Scrape away 1 proton bunch with vertical collimator
- Differences in scale, but sync-light and flying wires track well
- Effect of coupling on proton emittance at injection
- Preliminary work demonstrates reduced emittances of coalesced protons  (23  18 pi) by modifying skew quad circuits
- Skew quad changes also change tune – need more time
- Hopefully lead to reduced emittances of protons, pbars at 150 GeV

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## TEV RF noise – bunch length study

**TEV RF noise – bunch length study**

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Last Day Before Shutdown

- Lost pbar stack in shot-setup due to operator error
-    *No TeV store yesterday*
- MP02 regulation problems
- Experts came to replace regulator, tune-up extraction
- Could not prove stacking before turn-off
- Tune changes likely from earlier mistake
- No time to cycle busses before beam turned off
- First pbar transfer from Recycler to Tevatron!
- Shutdown of all machines began at noon on 1/12

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## RRMITEV  30% DC

**First pbars from Recycler into Tevatron**

- RR DC beam
- (E11)

- TEV DC beam
- (E10)

- TEV FBI bunch
- (E9)

- TEV SBD bunch
- (E9)

- RRMITEV  30% DC
-   11% into TeV bunches

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Coalescing Recycler Pbars in MI

- 1 of 4 pbar bunches

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Flying Wire Profile of A25 in Tev

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Recovering from 3.5 week shutdown

- Come up _quickly_ to pre-shutdown performance
- What to do when Tev gets beam?
- Get beam to circulate...
- Aperture scans, especially @ B0, C0, E17 (2 shifts)
- Fix orbits, tunes, chromaticities, coupling up ramp and through the squeeze  (6 shifts)
- Long p-only stores to check stability of C0 shunt  (2 owl shifts?)
- Do only necessary work to get machine up...optimize later.
- Try for first HEP store after 4 days with beam
- Stack & store for 1 week, then start dedicated studies aimed at exploiting larger C0 aperture
- Optimize injection helix to improve lifetimes at 150 GeV...
- Modifying helix means tedious effort to optimize feeddowns
- May need to realign CDF low beta quads after 4-6 weeks?

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03

## Summary

- Below average delivered luminosity:  3.5 pb-1
- 1 shift access, 5 shifts studies/maintenance, 1 lost store, 1 lost stack
- Encouraging results on reducing emittances of protons at injection into Tev by modifying coupling circuits
- Proof-of-principle: pbars extracted from Recycler and injected into the Tevatron!
- 3.5 week shutdown has begun – access everywhere

- R. Moore - FNAL

- All Experimenters' Mtg - 13 Jan 03