CesrTA Machine Studies Task Overview
I. Experiment Description
Experimental Topic
Classification*
Coordinator/
Experimenters
Primary Goals
Intrabeam Scattering
IBS
Michael
Dave Rubin, Jim Shanks, Walter Hartung, Suntao Wang,
Ehrlichman
Avishek Chatterjee
Gather beam size versus current in beams dominated by IBS.
Description†
1) IBS Decays with Electrons (6 hr)
-One of the nominal working points
-Size vs. current in LET, 50 pm-rad, 100 pm-rad, 150 pm-rad conditions
-2 hours setup + 1 hr per decay.
-IBS should be species independent.
-Experiments on both species help workout machine and instrument
systematics.
-Might detect non-IBS species-dependent effects.
2) IBS Decays with 2.1 GeV “eta free” lattice (6 hr)
-Positrons at nominal working point
-Size vs. current in LET, 50 pm-rad, 150 pm-rad conditions
-3 hours setup + 1 hr per decay
-Provides an IBS vs. damping time measurement
-Help validate "V15 managed" lattices
-Could other lattice problems be related to dispersion in the RF cavities?
3) Take IBS data at 2.5 GeV (5 hr)
-Size vs. current for LET, 50 pm-rad, 150 pm-rad
-1 hour setup + 1 hr for 3 decays
-2.3 GeV went smooth, let’s hope the same for 2.5 GeV
-Positrons at nominal working point
-Combine with 2.1 GeV and 2.3 GeV data to obtain an IBS vs. Current
result.
4) Strongly coupled beams (8 hr)
- After applying LET corrections, generate large amounts of xy coupling
to make a round-ish beam. Take size data at various currents.
-Beam lifetime should be long. Will need to scrape.
-This run could be one of our most interesting results. Ultimate storage
*
Machine Studies Classifications:
 EC – Electron Cloud
 LET – Optics Correction and Low Emittance Tuning
 IBS – Intra-beam scattering studies
 xBSM – x-ray Beam Size Monitor
 INST – Instrumentation (BPM development, RFA development, other)
 MDEV – Machine Development (includes injection configuration, injection tuning, custom orbit setup, instrumentation
preparation, etc.)
 MREC – Machine Startup (recovering conditions after down period or access)
†
Attach additional pages for experimental description if needed
1 of 3
ring designs use coupling to mitigate IBS. Our data could prove valuable to those
designs.
-Long shift requested because we will need the vBSM for the vertical
measurements, and we should allow for instrumentation work during the shift.
-Positrons at 2.1 GeV
-Maybe additional energies or with electrons if it goes well.
-Test whether Kubo method gives right result in the presence of strong
coupling.
Special
Needs/Requests
Prerequisites‡
Root fitter front-end
2.5 GeV V15 Lattice
Work out difficulties
with “eta free” lattice
Develop method for
creating coupled beam
For coupled beam
measurements: vBSM
needs to be ready
Time Requested§
25 hours
‡
§
1) Validate injection at 2.3 GeV and 2.5 GeV prior to IBS shifts
2) Obtain reasonable injection at the “exotic” space charge working points
prior to shift
3) Obtain reasonable injection for the “eta free” lattice
Personnel
Description
Michael
~30 line bash script that calls the root fitter, extracts the result,
Ehrlichman
populates MPM.
Dave Rubin
Nominal Qx>Qy or Qy>Qx working point
Jim Shanks
Dave Rubin,
Michael
Ehrlichman
Suntao Wang
No. Shifts
6 hr, 6 hr, 5 hr,
8 hr
Create coupled beam by using sextupoles or moving near
coupling resonance. Sextupole method is preferred, as
changing working point has lots of baggage.
A slit pattern was prepared for the December which would
allow large vertical beams to be measured with the vBSM.
This should be available for the April run.
Principal Tasks
1) Decays with electrons
2) Decays with “eta free”
3) Decays at 2.5 GeV
4) Strongly Coupled Beams
Indicate other machine work that is required in preparation for this machine studies experiment.
Indicate the principal shift topics and estimated number of shifts required
2 of 3
II. Machine Studies Assignments
Reserved for Project Management Team Use
Topic ID
Priority**
Shift Assignments
Date
**
Shift
Priority Scale:
1. Critical – results are necessary for preparation for subsequent down/run periods
2. Very high – results are strongly desired for achieving program milestones or in preparation for subsequent
down/run periods
3. High – results are of immediate interest but not require
4. Moderate – results should be pursued at the first convenient opportunity
5. Low – results are not presently a high priority for either project milestones or planning
3 of 3