8-26-2004 Run II talk Dave Johnson 1

SY120 Mixed-mode operation

Mixed-mode operation uses: oThe same optics in P1 and P2 beamline for stacking and SY120oThe same major dipole settings in P1/P2o Different dipole trim settings

Modes of operation for slow spill to SYo Dedicated slow spill (initial mode)o Mixed-mode (single batch to pbar, 7/9)o Mixed-mode (2 batch slip-stacking to pbar, 8/19)

All three modes use same MI ramp and timing, but different TLG modules All three modes have been commissionedThe minimum cycle time 2.8 sec The spill length is 655 ms

8-26-2004 Run II talk Dave Johnson 2

Optics ‘n Such

Before After

Stacking

SY120

400m

200m

500mMI

A0

F17

Beams-doc-1243

P1 P2 AP1

P2 P3

Want to start with a matched solution for new SY tuneNew lattice ‘n orbit installed July 9th

Changed P1 & P2 quads

Q703 fixed

AP1 quads fixed

8-26-2004 Run II talk Dave Johnson 3

Simple mixed-mode Slip-stacking mixed-mode

Beam to pbar

Beam to SY

Pbar batchesSY120 batch

RF recapture

Qh

QXR

Two flavors of Mixed-mode (1 or 2 batch to Pbar)

Losses @F18

8-26-2004 Run II talk Dave Johnson 4

Issue: losses during acceleration w/ slip stacking

1st batch

2nd batch

3rd batch

recapture

Need to adjust slip stacking curves to shift recapture time to finish before SY120 batch injected

Data from Kiyomi

8-26-2004 Run II talk Dave Johnson 5

Issue: Orbit through F17 and losses in Tev at F18

F17 AP1 c-magnets

F17B3

T:LMF18

3v

Safe level (1/4 v)

Raise upstream c-magnet interface (~ 1/3 inch) to center lower beam pipe on P2-P3 median plane Install V Trim at F18

SY120AP1

1.75” OD

-8mmP2 line

F17 6-8mm oscillation in P3

8-26-2004 Run II talk Dave Johnson 6

Issue: Mixed-mode Cycle Duty Factor

TLG with 4 sec rep (withother study cycles)

4 sec rep

5 sec rep

Rms current H618

12 a

8a

What to do? >Quad moves (reduce corr. current)

>Cooling plates (as done for NuMI)

Trip limit

8-26-2004 Run II talk Dave Johnson 7

Issue: Spill Duty Factor

100 ma/div

QXR20A FS RFSPILL

MHIERR

Beam

Recall, that the horizontal quad bus produced a measured tune shift of0.0146 /amp => 70 mA will produce a 0.001 tune shift which is the equivalent to 10 amps on QXR (2 magnets).

EE Support implemented feedback to stabilize average level of Qh and Qv due to asymmetric TLG

St

Not been focused on up to this point Starting point –> model system over shutdown and implement feedback using MHIERR as input to kHz bandwidth bucker system.Need beam studies for commission bucker system

From 4/2004 RunII meeting