# Presentation: 804895

## Proton Economics

- Eric Prebys
- FNAL Accelerator Division

## Proton Team (“Finley Report”)

- Group formed in early 2003 to study proton demands and needs for the “near” future (through ~2012 or so), in the absence of a proton driver.
- Work culminated in a report to the director, available at www.fnal.gov/directorate/program_planning/studies/ProtonReport.pdf
- No big surprises [see P. Kasper “Getting Protons to NuMI (It’s a worry)”, FNAL Beams-doc-1036, 2001].
- This work will form the basis of “The Proton Plan”.

## General Comments

- The linac is not currently a performance bottleneck for the complex *when it is running stably.*
- There are ongoing longevity and reliability concerns in the linac
- General state of instrumentation is inadequate to characterize linac behavior
- The 7835 tubes from Burle continue to be a major concern, although the situation is better than it was a year ago.
- There are new worries about the klystrons, which we formerly believed were not an issue.
- There are some other longevity issues, if we expect the linac to last another ~10 years.

## What Limits Total Proton Intensity?

- Maximum number of Protons the Booster can stably accelerate: 5E12
- Maximum average Booster rep. Rate:  currently 7.5 Hz, may have to go to 10 Hz for NuMI+ *(full)* MiniBooNE
- (NUMI only) Maximum number of booster batches the Main Injector can hold: currently 6 *in principle*, possibly go to 11 with fancy loading schemes in the future
- (NUMI only) Minimum Main Injector ramp cycle time (NUMI only): 1.4s+loading time (at least 1/15s**nbatches*)
- Losses in the Booster:
- Above ground radiation
- Damage and/or activation of tunnel components

*Our biggest worry at the moment!!!!*

## Proton Demand

- Can we do this???

## Projects in 2003 (a short list)

- 2003 Activities centered around preparation for the September shutdown:
- Linac water system upgrade
- New Linac Lambertson
- Better optics in 400 MeV line
- Booster two-stage collimation system
- In the works a long time
- Now in place.
- Major modifications at main extraction region
- Address “dogleg problem” caused by extraction chicane system.
- New, large aperture magnets in extraction line:
- Should reduce above-ground losses
- Major vacuum system upgrade.
- Lots of smaller jobs.

## New Collimator System

- Should dramatically reduce uncontrolled losses

- Basic Idea...

- A scraping foil deflects the orbit of halo particles...

- ...and they are absorbed by thick collimators in the next periods.

## Long 3 Dogleg Work

- Increase spacing between dogleg pairs from 18” to 40” to reduce lattice distortions at injection.

- New magnet to match extraction line

## How are We Doing?

- “Mysterious” Performance Problems

- Power loss (W)

- Protons (p/min)

- Energy Lost (W-min/p)

- Big Shutdown

- BooNE turn-on (Sept. 2002)

## Recent Running (Last 4 Weeks)

- Power loss (W)

- Protons (p/min)

- Energy Lost (W-min/p)

- Record Performance

- Several Unrelated Problems

## How far have we come?

- Time (s)

- Before MiniBooNE

- Now (same scale!!)

- Energy Lost

- Charge through Booster cycle

- Note less pronounced injection and transition losses

## Near Term Priorities (Booster)

- Optimizing Booster for improved lattice:
- Tuning and characterizing 400 MeV line (Linac to Booster).
- Tuning Booster orbit to minimize losses.
- Commission Collimators:
- Estimate another month or so to bring into standard operation. (discussed shortly)
- Aperture Improvments:
- Alignment (discussed shortly)
- Orbit control
- Abandoning our original global plan in favor of local control at problem spots for the time being.
- Prototype RF Cavities
- Two large aperture prototype cavities have been built, thanks to the help of MiniBooNE and NuMI universities.
- We will install these as soon as they are ready to replace existing cavities which are highly activated.
- Multibatch timing: Beam cogging

## Collimator Studies

- Shown is the effect of putting in one of the secondary collimators as a percentage change in losses as a function of time around the ring.
- Studies are continuing.
- “Rapid response team” will be put on problem.
- At present, primary collimators are not optimized to energy loss profile
- Will replace in upcoming shutdown.

- location

- Collimator location

## Alignment Problems

- Working closely with AMG
- As opportunity allows
- Fix vertical orbit
- Align RF cavities
- Over the next year
- Complete network
- Integrate with MAD
- Make a horizontal plan.

- Effect of Booster tower shielding

- 1⁄4” Misalignment at Collimators!

## Priorities over the Next Year

- Linac Characterization and Reliability
- Increase instrumentation of old linac to study instabilities.
- Develop set of performance parameters.
- Booster improvements.
- Prepare for modification of second extraction region
- New septum
- Modified dogleg magnets
- On track for next year’s shutdown.
- Injection bump (ORBUMP) improvements:
- Injection Bump (ORBUMP) Power Supply
- Existing supply a reliability worry.
- Limited to 7.5 Hz
- Building new supply, capable of 15 Hz.
- Aiming for summer shutdown (aggressive, but doable)
- New ORBUMP Magnets
- Existing magnets limited by heating to 7.5 Hz
- Working on a design for cooled versions.
- These, with a new power supply, will make the Booster capable of sustained 15 Hz operation.
- Aiming for summer shutdown (aggressive, but doable).

## Planning for the future

- In response to the “Finley Report”, the lab management has asked for a “Proton Plan” for the proton source over the next few years, analogous to the Run II plan, but much lower in scope.
- The plan is to do what we can reasonably do to maximize the throughput and reliability of the existing proton source (incl. MI), under the assumption that a Proton Driver will eventually be built.
- Beyond the things I have already mentions, the scope is largely determined by the budgetary guidance:
- FY04:  $0-2M
- FY05: $6M
- FY06: $5M
- FY07: $5M
- FY08: $2.5M

## Comment on the Budget

- This budget is more than enough to do the basic things that we must do to keep the proton source going, provided some of it appears this year!
- It *precludes* certain ideas that have been suggested:
- New Linac front end, or any significant 200 MHz upgrade.
- Decreasing the Main Injector ramp time
- Which means there will be very little to do with the Main Injector.
- There are some “big” (>$1M) projects that must be discussed.

## Large Projects Under Consideration

- Booster RF system:
- Commission a design for a new booster RF system
- Larger aperture, higher gradient cavities
- Solid state distributed amplifiers
- Goal to have design by January 2005.
- Two year timescale to build and install (perhaps solid-state DA’s can come sooner).
- Cost ~all of it.
- Adding two additional cavities
- Use university prototypes + spare parts
- Cost ~$500K
- 30 Hz harmonic to booster ramp.
- Effectively increases RF power
- Cost of order $1-2M
- New LEL quad power supplies.
- A significant reliability worry
- Cost of order $1M.

## Schedule for the Plan

- Will proceed with the vital projects for this year.
- Hope to have a skeleton of a plan by the end of this month.
- Will have a more detailed plan and major recommendations by this summer.

## Expectation Management

- What we really think we can achieve:
- Slipstacking to provide 1E13 protons per pulse for pbar production.
- 5E20 protons to MiniBooNE by the time NuMI fully comes on in early 2005
- 2-2.5E20 p/yr to NuMI in the first year of operation.
- Increasing that over the next few years, to something over 3E20 p/yr.
- What we might achieve:
- Continuing to operate the 8 GeV line at some significant level *after* NuMI comes on, ultimately delivering 1E21 protons to MiniBooNE and possibly supporting other experiments (e.g. FINESSE).
- Delivering as many as 4E20 p/yr to NuMI, at which point things will be limited by Main Injector aperture and cycle time (with the present source, anyway).
- It would be unrealistic to believe:
- We will ever send more than 4E20 p/yr to NuMI without significant (~$100M) investment in the existing complex.
- That would be direct competition for resources with the current Proton Driver proposal.