# Presentation: 783691

## Beam/Booster Status and Plan

*Eric Prebys*
- Booster Group Leader
- FNAL Beams Division

## Autotune Now Working!!!

-  Now stable and working.
-  Typically left running for long periods.
-  Training operators to use.
-  Should be able to handle *small *changes due to Main Injector injection closure.

## 870 Aperture Problem

- Moved multiwire from 871 to 870 to look at beam size.
- Guess what?  It was big.
- All quads (powered and permanent) now checked – OK.
- Not well understood.
- Not a big issue (except to the extent it means we don’t understand our beam).

## Beam Angle Problem

- H

- V

- Center

- Center

-  Looks like beam off by ~10 mr horizontally.
-  Is this possible? (Could also be bad loss monitor gains).
-  How big a problem is this.

- Dead channel

## How are we Doing

- Wrong Magnet Move

- Right Magnet Move

- Still seem to be stuck at the E16/hr limit

## Limiting Factors (Last Two Weeks)

- Limit

- Booster Power Loss (will raise limit next week)

- MP02 Temp

- MiniBooNE rate (p/hr)

- Wrong Magnet Move

- Right Magnet Move

## Change of Management

- Proton Source Dept.Head: Bob Webber

- Linac GroupLeader: Elliot McCrory

- Booster GroupLeader: Jim Lackey

- MiniBooNE Beam LineMach. Coor.: Craig MooreDeputy: Eric Prebys

- Proton Source Dept.Head: Elliot McCrory

- Linac GroupLeader: Elliot McCrory

- Booster GroupLeader: Eric Prebys

- MiniBooNE Beam LineMach. Coor.: Craig MooreDeputy: ???

## Division of Responsibilities

- Me:
- Achieving maximum number of protons out of the Booster.
- Addressing Booster beam quality issues (e.g. longitudinal damping).
- Address Time Line Issues
- Craig + ??:
- MiniBooNE beam line issues.
- Access coordination.
- Optimized MiniBooNE running.

## Problems During Shot Setup/Study Periods

- Problem during final proton loading:
- Final protons use short batches (7/84 bunches).
- These follow a slightly different path (or are at least measured to).
- Injection closing for these protons starts upstream of the switch magnets, so it affects our beam line
- Autotune might be able to correct for this, but the loss monitors trip before it has a chance to.
- Bruce Brown and Dave Capista is working with data from Tom Kobilarcik to automatically bump magnets in our line to compensate for MI-8 changes.
- Long super cycle problem
- When the TeV is ramping, they switch from a 60 sec to a 220 second super cycle.
- When a lot of MiniBooNE pulses are put into this, the Main Injector ramp shifts one tick too early on stacking pulses, causing the Booster to lose beam a phase lock time.
- Not fully understood.  Linden Carmichael (back from vacation) is working on it.

## Problems During Shot Setup/Study Periods (cont’d)

- Sparse time line problem
- To save Booster pre-pulses, MiniBooNE “trailer-hitches” to existing cycles.
- During shot setup, there aren’t many of these, so we end up with very long (2 prepulse+1 M.I. + 10 MiniBooNE = 13) pulse trains.
- This can instantaneously exceed the limiting rate counters (which average over 16 seconds).
- Facility to automatically build new, dedicated MiniBooNE modules is very inefficient (2 prepulses for every MiniBooNE pulse).
- Linden Carmichael is also working on this.
- Operator attention problem
- Need more oversight from the experiment
- Revive “beam liason” idea???

##  Minimum Staffing Needs (as told to DOE)

- Crisis (needed to maintain current level of performance):
- 1 Engineer III+ to take charge of low level RF system.
- 1 Tech/Engineer to assist.
- For any hope of improvement:
- 1 Full time accelerator physicist to help orchestrate performance studies.  (Need at least 50% FTE of someone who knows accelerator physics or 25% FTE of someone who knows accelerator physics+controls). Maybe from BP.
- 1 Engineer to help oversee large projects (collimator shielding,Large aperture RF, etc.)

## (Roughly) Prioritized Booster Project List

- Fix what’s broken today!!! (everybody)
- Collimator shielding (first design review complete, hope to have ready for “January” shutdown, or incremental installation).  (Alex Chen, Jim Lackey)
- New extraction septum power supply (finished, ready to connect). (Chez Jach)
- Ramped orbit correctors (high intensity transport demonstrated, being optimized). (Eric Prebys, Linda Coney)
- New extraction septum magnet (finished, being tested, ready for “January” shutdown). (Jim Lackey + MF)
- Automated Ramp Monitor Program (J. Guglielmo [CD]).
- Longitudinal Damping system upgrade (being designed). (Bill Pellico)
- Large aperture RF cavities (powered prototype tested, vacuum-ready new prototype ready “in the spring”, may need to redline whole system if other ideas don’t pan out). (John Reid).
- Low Level RF upgrade (could suddenly jump up in priority if things start to fail). (????)

*This list does not include ongoing studies to understand Booster performance*

## Some of Specific Studies

- Understanding fundamental machine characteristics:
- tunes
- chromaticity
- Injection:
- Dependence on injected bunch width
- Dependence on injected bunch overlap
- Dependence on RF capture parameters
- Space charge: coherent tune shift, incoherent tune spread, etc.
- Transition:
- Detailed study of loss mechanisms through transition and after.
- Gamma-t jump??

## List of Projects for “January” Shutdown

- Install new MP02 magnet
- Install collimator shielding
- Install new MI-8 bend (EDWA) magnets (reduce losses in MI-8).
- Install new Lambertson at end of Linac (reduced fringe fields will improve significance of dump Linac dump studies).

## Good News from DOE Review

- Even though it was a collider review, DOE made some specific recommendations wrt. proton source
- Increase support and staffing for proton source.
- Encourage more involvement from Beam Physics.

## Hard Questions

- Quantitative overview of tunnel loss concerns:
- Damage thresholds not understood at any level – try to keep losses within a factor of two of historical levels. *(reviewers suggested installing dose monitors in the tunnel)*
- Try to keep activation at a level where a single crew can do “typical” service operations.
- Quantitative improvements from ongoing projects
- Collimators: factor of 2?
- Orbit control: factor of 2, maybe?
- Better understanding of instabilities:  a bit?
- Improved monitoring/reliability: a bit?
- This does not get us to the required intensities.
*In the ensuing conversation, I agreed that a factor of 3-5 over present performance was a “reasonable” goal.*

## Impact of MiniBooNE on Collider

- No direct impact *by definition*
- Pbar and collider get whatever protons they want.
- MiniBooNE gets whatever it can after that.
- Indirect impacts
- Negative
- Increased Booster loss trips
- Increased failure rate of pulsed components (not seen yet)
- Increased cooldown time due to activation.
- Positive
- More consistent Booster performance because of closer attention.
- Better understanding of Booster will lead to superior performance for the collider.
- Bottom Line:
- Collider luminosity (peak and integrated) have gone up about 50% since MiniBooNE started running.
- It is unlikely that MiniBooNE will ever have a significant effect on collider operation.