# Presentation: 199478

## Limitations to Total Booster Flux

- Total protons per batch:  4E12 with decent beam loss, 5E12 max.
- Average rep rate of the machine:
- Injection bump magnets (7.5Hz)
- RF cavities (7.5Hz, maybe 15 w/cooling)
- Kickers (15 Hz)
- Extraction septa (now 4Hz, 7.5 after Jan. shutdown)
- Beam loss
- Above ground:
- Shielding
- Occupancy class of Booster towers
- Tunnel losses
- Component damage
- Activiation of high maintenance items (particularly RF cavities)

- Of particular interest to NUMI

- Our biggest concern

## Some Cold Hard Facts for the Proton Source

- Running as we are now, the Booster can deliver a little  over 1E20 protons per year – this is about a factor of five over typical stacking operations, and gives MiniBooNE about a fifth of their baseline.
- NuMI will come on line in 2005, initially wanting about half of MiniBooNE’s rate, but hoping to increase their capacity – through Main Injector Improvements – until it is equal to MiniBooNE.
- Whatever the labs official policy, there will be great pressure (and good physics arguments) for running MiniBooNE and NuMI at the same time.
- -> By 2006 or so, the Proton Source will be called upon to deliver 10 times what it is delivering now.
- At the moment, there is NO PLAN for achieving this, short of a complete replacement!

## Typical Booster Cycle

- Various Injected Intensities

- Transition

- Intensity (E12)

- Energy Lost (KJ)

- Time (s)

## Proton Timelines

- Everything measured in 15 Hz “clicks”
- Minimum Main Injector Ramp = 22 clicks = 1.4 s
- MiniBoone batches “sneak in” while the MI is ramping.
- Cycle times of interest
- Min. Stack cycle: 1 inj + 22 MI ramp = 23 clicks = 1.5 s
- Min. NuMI cycle: 6 inj + 22 MI ramp = 28 clicks = 1.9 s
- Full “Slipstack” cycle (total 11 batches):
-         6 inject+ 2 capture (6 -> 3)+ 2 inject+ 2 capture (2 -> 1)+ 2 inject+ 2 capture (2 -> 1)+ 1 inject+ 22 M.I. Ramp----------------------39 clicks = 2.6 s

## Summary of Proton Ecomomics

- Booster Hardware Issues

- Radiation Issues

- MiniBooNE baseline  5E20 p/year

- *assuming 5E12 protons per batch

- NUMI “baseline” = 13.4E12 pps x 2E7 s/year  2.7E20 p/year

- Right now we’re at roughly 1/5 of the MiniBooNE baseline

## Booster Losses (Normalized to Trip Point)

- BRF11: 200 mR/hr @ 1ft

- BRF15: 300 mR/hr @ 1ft

## Hardware Improvements to Booster

- Shielding and reclassification of Booster towers: complete 2001
- New extraction septum (MP02) power supply: complete 11/02
- New extraction septum: magnet complete.  To be installed 1/03
- Collimation system: complete, but cannot be used until...
- Collimation system shielding: 75 tons of steel to be stacked 1/03
- Time line improvements (very important for MiniBooNE operation): more or less complete.
- More cables for extraction septum (will allow 15 Hz operation): ??
- New injection bump magnets: ??
- New RF cavities: ??

## Plan

- All near term hardware improvements will be complete by end of Jan. shutdown.  At the point the Booster will physically be able to run a 7.5 Hz.
- Proceed with tuning improvements (C. Ankenbrandt coor.):
- IPM calibration (Tomlin, Spentzouris, Lackey).
- Orbit correctors: complete, working out operational issues (Prebys, Coney).
- Precision lattice measurement: (Lackey, Coney, new grad. Student).
- Transition studies (gamma-t jump??): (Jackson et al.)
- Damping improvements: Pellico + ??

## New RF System

- The existing RF cavities form the primary aperture restriction (2 1⁄4” vs. 3 1⁄4”).
- They are high maintenance, so their activation is a worry.
- There is a plan for a new RF system with 5” cavities:
- Powered prototype built
- Vacuum prototype ready for summer installation
- Second prototype to be built by university machine shops?
- Total cost: $5.5M cavities + $5.5M power supplies (maybe use old ones)
- Is it worth it? On of the questions for the study group is how much improvement we might expect.

## Of Particular Interest to NuMI (and not to MiniBooNE)

- Per batch intensity (MiniBooNE can make it up in rep rate).
- Longitudinal emittance (needed for elegant M.I. Loading schemes).
- M.I. cogging for multi-batch operation (Webber will discuss).
- Operational issues (I.e. running during shot setup).  These were a big deal for MiniBooNE.  They will be totally different for NuMI.

## Bottom Line

- The proton source is currently delivering about 1/5 of what MiniBooNE wants.
- NuMI would like similar numbers of protons.
- It’s very likely that MiniBooNE and NuMI will want to run together, meaning we’d like to increase proton output by a factor of 10.
- Our current plan will likely double or triple the present output.
- There is a yet no clear path beyond that.

## Upgrade Cost Estimate

- Summary:
-  ~$260K per cavity, of which $160K goes for the three tuners.
-  A roughly equal amount for the power supply chain.
-  About 20 cavities.
- -> $11M total

## Questions to Answer

- Accuracy of the Cost Estimate?
- Status:
- First prototype
- Vacuum prototype
- Design
- Reasonable timeline.
- Ways to save money:
- Use old tuners?
- Use existing power supplies?
- Ways in which universities can help:
- Political pressure
- Money
- Fabrication

## Some Issues

- What is the best stacking procedure? Three in parallel or one at a time?
- How much manpower and time will we need?
- What are the radiation budget implications? Fields near the collimators are 5-10 mR/hr.
- Can we take advantage of help offered by MiniBooNE?
- Are there any modifications which should be made to the collimator stands to facilitate later servicing when they’re hot?