# Presentation: 797328

## Week in Review: 12/2/02 -12/9/02

**  ****Ron Moore – FNAL**

- Store Summary (Studies Week)
- Studies Review
- Schedule for Week

- All Experimenters' Mtg - 16 Dec 02

## Store Summary

| Store | Initial
Lumi | Deliv’d
Lumi | Termination | Comments |
| --- | --- | --- | --- | --- |
| 2049 | 24.8 | 888 | Intentional | Tev dampers off; pbar RF problem affects coalescing in MI |
| 2070 | 33.2 | 1479 | Intentional | Tev feeddown changes on ramp; pbar ARF1 problems again |
| 2072 | 31.4 | 1383 | Intentional | ARF1 problem again, but finally understood |
| 2074 | 27.0 | 1215 | Intentional | First shot with pbar ARF1 fixed |
| 2076 | 31.2 | 1567 | Intentional | Minor chromaticity decrease in Tev ramp |
| 2078 | 28.4 | > 500 | ongoing | Proton bunch length blow-up at 980 GeV |

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Slide 3

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Slide 4

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Slide 5

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Lifetimes @ 150 GeV with/without dampers

**Store 1953**
**Dampers ON**

**Store 2072**
**Dampers OFF**

**Lost 15% pbars**
**@ 150 GeV**

**Lost < 2% pbars**
**@ 150 GeV**

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Tevatron Studies

- Emittance Growth up ramp
- See some growth with uncoalesced and coalesced
- On central orbit and both helical orbits
- Still not completely understood
- Adjusted feeddowns on ramp   (tunes on helices)
- Transverse dampers
- Vertical damper causing horizontal excitations
- Dampers sensitive to Tev coupling
- Keeping dampers off until noise measurements and coupling adjustments @ 150 GeV are made
- Octupole usage at 150 GeV
- Can improve proton lifetime at 150 GeV
- Coupling changes on helix troublesome
- Needs more study time

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Tevatron Transverse Dampers

- Vertical ON

- Horizontal OFF

- Vertical damping OK,
- but exciting Horz lines

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Pbar Studies/Maintenance

- Stacktail compensation with directional couplers
- Tried with 200 mA stack
- Suppressed signal from core, but stacking deteriorated
- Ni vs Inconel targeting study
- 1-2% better yield with Ni for smallest spot sizes
- Yield is less than models predict
- Aligned Debuncher Notch Filter band #2
- Creating DRF1 curves to bunch reverse protons in 53 MHz (to send up AP2 line)

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Debuncher Notch Filters

- as found

- after alignment

- Green - PB1 ; Red - PB2; Cyan - PB3; Magenta - PB4;   Yellow - all systems

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Record Pbar Stack

- Kept stack meant for HEP shot Monday night
- Continued stacking as part of studies
- Accumulated 225 mA stack     (previous 221.25 mA)
- Took 2 hours to cool stack before changing lattice
- Poor lifetime during that time, too.
- No beam lost going to shot lattice, lifetime recovered
- Emittances as expected from smaller stacks
- For shots, extracted 168 mA from 213 mA, took rest back to stacking lattice for next HEP shot

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Pbar Production Versus Stack Size

- Stack Rate
-  (mA/h)

- Prod Eff
- (E –6)

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Other studies

- Main Injector
- Continued 27 GeV coalescing/2.5 MHz studies
- Continued proton slip-stacking studies
- Recycler
- Completed aperture scans
- Measured admittance = 64 (H), 46 (V)
- Measured momentum aperture = 1.5%  full width

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Maintenance

- Linac RF station 5 – PA replaced (again!)
- Tube had only ~6000 hours
- Tube in place had been rejected by manufacturer
- Have only one spare
- A3 cryo vacuum
- Dead turbo cart replaced
- Vacuum spoiled in repair, took long time to recover
- ARF1-2 phase feedback
- Preventing pbars from having nice 53 MHz structure
- Adjusted feedback signal drifted out of stable region

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Dedicated Pbar Shots to Recycler

- Elvin Harms is coordinator
- Charge from Steve Holmes
- “The goal is to achieve in a reliable manner an 85% stacking efficiency in the Recycler and shot times (defined as the interruption in Pbar Source stacking) of under an hour.”
- After every HEP shot...
- Take leftover pbars back to stacking lattice  (~10 mA)
- Stack to 30 mA, shoot to Recycler
- Tune up transfer lines while stacking
- Begin stacking for next HEP shot
- No more “shots off bottom” from shot lattice
- No shots to Recycler during studies periods
- Expect < 10% drop in delivered luminosity

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Weekly Schedule

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02

## Summary

- Best delivered luminosity with studies:  6 pb-1
- Record pbar stack = 225 mA
- Elvin Harms coordinating stacking and pbar shots to Recycler after every HEP shot
- Shutdown 12/17 for safety system tests and accesses (06:00 – 17:00)
- 3-3.5 shifts of dedicated studies this week
- Try to get Tev transverse damper(s) back on for HEP shots
- Resume “stack and store” following studies until week after Christmas

- R. Moore - FNAL

- All Experimenters' Mtg - 16 Dec 02