# Presentation: 512846

## Proton PlanStatus and Projections 

- Eric Prebys

## Proton Plan Charge

- Develop a plan for a reasonable set of improvements and operational initiatives to  maximize proton delivery to NuMI and the Booster Neutrino Beam (BNB)
- Estimate the budget and timeline for these improvements.
- Estimate proton delivery to both beam lines if the Plan proceeds on schedule.
- Note:
- This project precedes other work that must be done to support the NoVA program
- This project precedes a proton driver or other significant improvements to the complex that are under discussion.

## Limits to Proton Intensity

- Total proton rate from Proton Source (Linac+Booster):
- Booster batch size
- ~4-5E12 protons/batch
- Booster repetition rate
- 15 Hz instantaneous
- Prior to 2006 shutdown: 7.5Hz average (injection bump+RF)
- Now: 9 Hz (including conditioning pre-pulses)
- Beam loss
- Damage and/or activation of Booster components
- Above ground radiation
- Total protons accelerated in Main Injector:
- Maximum main injector load
- Six “slots” for booster batches (3E13)
- Up to ~11 with slip stacking (4-5E13)
- Some RF issues
- Cycle time:
- 1.4s + loading time (1/15s per booster batch)

- Historically our biggest worry

## NuMI Operating Modes

- Initial NuMI operation (“2+5”):
- Two batches slip stacked for antiproton production.
- Five more batches loaded for NuMI
- All will be accelerated together.
- This is the current standard operation.
- Ultimate NuMI operation (“2+9”):
- Five batches will be loaded into the Main Injector, leaving one empty slot.
- Six more batches will be loaded and slipped with the first to make two for antiproton production and 9 for NuMI.
- This is under study, but will probably not result in a net increase in protons until after the next shutdown

## Context: Staged Approach to Neutrino Program

- NuMI era (concurrent with Run II)
- Ramp up to deliver slip stacked protons to both NuMI and antiproton production
- Continue to deliver protons to the 8 GeV line at some level
- Goal:
- ~400 kW to NuMI
- 1-2E20 protons to 8 GeV line
- S(uper)NuMI era (after collider program)
- Use Recycler as a pre-loader to the Main Injector to eliminate loading time
- Details being worked out. Becoming a formal plan.
- Goal
- ~700 kW to NuMI line
- SNuMI 2 (tentative)
- Use Antiproton Accumulator Ring to momentum stack protons
- Boxcar stack these protons into Recycler
- Load into Main Injector
- Goal
- ~1.2 MW to NuMI line
- Proton Driver?
- Always a possibility, but not part of our baseline thinking at the moment.

- Proton Plan

## Goals of Plan

- 120 GeV (NuMI)
- Accelerate 4-5E13 protons per 2.2s cycle
- This alone is within demonstrated performance of the Booster (at least in terms of total protons):
- 7.5Hz adequate
- Total proton rate ~OK
- Most of the necessary work is in Main Injector
- Maintaining acceptable longitudinal quality from Booster for slip stacking presents an operational challenge
- 8 GeV (BNB)
- Maintain ~2e20 p/year to maintain 8 GeV neutrino program
- Requires ~50% increase in total protons
- Requires Booster to go to ~9Hz
- Future
- Pave the way for increased beam throughput needed by SNuMI and beyond

## Plan Strategy

**Increase the proton delivery from the Booster (to both NuMI and BNB)**
- Increase acceptance by improving orbit control, beam quality, etc
- Increase maximum average Booster repetition rate
**Increase the beam intensity in the Main Injector for NuMI**
- Main Injector multi-batch operation
- 5 single batches to NuMI
- ->9 slip stacked batches to NuMI
- Identify and ameliorate loss and rep. rate issuess
- Might require RF improvements.
**Improve operational reliability and stability**
- Alleviate Low Energy Linac PA tube (7835) Problem
- Linac quad supplies and Low Level RF
- Booster RF?

## Proton Plan Time Line

- 11/04: First draft of “proton Director’s Review, August 2005
- 8/05:  First Director’s Review
- 9/05: “Baseline”
- Since baseline:
- Plan carefully tracked with monthly PMG meetings
- Change control through formal change request (CR) procedure.
- So far, 19 CR’s of varying magnitude

## Significant Elements of Plan

- Linac
- Stockpile two year supply of spare 200 MHz power amplifier tubes (7835’s), in the event of an interruption in supply
- Characterize and improve Low Energy Linac Low Level RF
- Booster:
- Replace and reconfigure injection bump (ORBUMP) system.
- Relocate 8 GeV dump from Booster tunnel to MI-8 transfer line
- Make Booster robust to 9 Hz, and understand requirements to go to 15 Hz
- Design, build, and install new corrector system
- Main Injector:
- Replace seven quadrupoles with increased aperture versions, to reduce injection and extraction losses.
- Operationally develop multi-batch and multi-batch slip stacked operation
- Design and install collimation system, both in the MI-8 line and in the MI ring
- Modify injection kicker to allow multi-batch slip stacked operation
- Characterize and perhaps make improvements to RF system, to support high intensity operation.

- Red = completed by end of shutdown

## Major 2006 Shutdown Projects

- Linac
- Used shutdown to make characterization measurements needed for LLRF project (1.1.4.1.1)
- Booster
- New injection bump (ORBUMP) scheme installed and 400 MeV line reconfigured (1.2.2)
- RF cavity drift tube cooling completed (1.2.7)
- One of the two extraction regions removed from Booster and relocated to the MI-8 transfer line (1.2.11)
- New 13.8 kV tranformers and switch gear installed for Booster RF system (1.2.13.1)
- Significant non-Plan Booster projects:
- 400 MeV line LVPS replacement
- Sump water rerouting
- Main Injector
- Seven large aperture quad magnets installed to eliminated aperture restriction (1.3.1)
- Collimation system installed in MI-8 line (1.3.2.2)
- MI-10 kicker modified to allow rep. rate needed for slip stacked NuMI operation (1.3.3.2)

## Effect of Shutdown work

- ORBUMP
- New injection scheme works well
- Injection orbit slewing reduced from ~1cm to about 2mm
- Removed rate issue
- Booster dump relocation
- New dump works fine
- Now able to maintain a more stable orbit during acceleration in Booster
- MI-8 collimation
- Not yet commissioned
- Main Injector Large Aperture Quads
- Significantly increased aperture (see Kourbanis’ talk)
- MI-10 kicker
- Now capable of full slip stacked operation
- Better pulse quality

- -> Record Booster Intensities

## Summary at a Glance

- = 	Task completed during shutdown

- = 	Significant element completed 	during shutdown

- New 13.8 kV transformers and switch gear for Booster RF

- MI-8 Collimation Complete

- MI-10 kicker upgrade

- = 	Non-shutdown task completed

- =	Task descoped

## Future

- A significant part of the Proton Plan was completed (or descoped) by the end of the recent shutdown.
- This will free up some badly needed expertise to focus on optimizing the system to take advantage of the improvements that have been made.
- The most significant remaining tasks are:
- Linac LLRF (1.1.4)
- Booster Corrector System (1.2.3)
- This would be a major project all by itself
- Main Injector Ring Collimation (1.3.2.1.3)
- Main Injector RF Upgrade (1.3.4)
- Series tube modulator power dissipation
- Anode power supply rectifier transformer
- Solid State Driver power supplies

## Where we stand with respect to NuMI

- The Booster has demonstrated the performance necessary to deliver the protons and quality necessary for ultimate NuMI performance.
- Remaining Booster projects are aimed at providing overhead for 8 GeV operation, maintaining stable operation, and laying the groundwork for SuperNuMI.
- The Main Injector has demonstrated full 2+5 operation.
- Things remaining to be done for 2+9 NuMI operation
- MI ring collimation
- Conceptual review passed
- On track for construction and installation in the 2007 shutdown
- MI Upgrades
- On track (if we get resources) for 2007 shutdown

## Procedure for estimating Proton Delivery

- Assume traditional operational priority:
- Protons for pBar production
- Limited by ability to slip stack
- Limited by max cooling rate
- Protons for NuMI
- Limited by max Booster batch size
- Limited by max MI cycle rate
- Limited by max MI proton capacity
- (will be) limited by ability to slip stack NuMI protons in MI
- Protons for BNB (currently MiniBooNE)
- Determined by difference between Booster capacity and maximum MI loading.
- Currently limited by Booster lossesUltimately limited by Booster rep. rate.
*Extremely* sensitive to fluctuations in total Booster output

## Important Milestones

- 2006 Shutdown
- Maximum Booster rep. rate increases from 7.5Hz->9Hz
- Main Injector Improvements will allow studies of full 2+9 operation
- Assume beam loss in Main Injector limits us to 2+5 as standard operation.
- 2007 Shutdown
- Installation of half of Booster correctors will allow increased throughput
- Collimation and RF Improvements in the Main Injector will allow operational slip stacking (2+9) operation to NuMI
- 2008 Shutdown
- With the installation of last Booster correctors and improved gamma-t magnets, all Proton Plan projects complete.

## Estimating Booster Output

- History has shown that the lab tends to overestimate the benefits of particular improvements.
- Tuning and optimization take a long time
- Tend to asymptotically approach the goal, then get distracted by other things.
- So we...
- Evaluate the potential of particular improvements based on effective aperture increase or uncontrolled beam loss reduction:
- For example, if something reduces uncontrolled loss by 10%, it has the potential to allow us to send 10% more beam.
- Consider the following scenarios:
- “Design”: After *one year* of tuning, we realize *half* of the potential benefit.
- “Fallback”: After *one year* of tuning, we realize *one quarter* of the potential benefit.

## Peak Booster Intensities

- These are “peak” numbers
- An “average to peak” correction is applied to get average values
- These are the numbers from loss limits
- The real peak value will be limited by the 9Hz rep rate at about 1E17, depending on batch size.

## Factors Considered in FY05, FY06 Projections

- Linear ramp-up to see benefit of improvements
- Slip stacking efficiency
- Done in a confusing way (more about this later)
- Annual shutdowns (assume 2 mo/yr)
- Uptimes: based on MiniBooNE 2004
- Peak to average corrections
- For BNB, based on MiniBooNE 2004
- For NuMI, used reasonable guess
- Effects of shot setup
- Implemented as VB routines in Excel spreadsheet
- Easy to modify

## How are we doing so far?

- Compare NuMI and MiniBooNE to FY05 and FY06 “blue and red” curves
*Approximately *equal to Proton Plan projections shown at last review
- General comments
- Booster peak intensities have not been quite as high as projected
- NuMI rate has been severely affected by unplanned down times
- MiniBooNE benefited significantly from these downtimes

## Total Protons Through Booster

- Turn on slower than expected

## Protons to NuMI

- Water in target

- Horn ground fault (loose foot)

- Tritium in water

- Special runs

- Resin beads in water system

- Note: without slip stacking, NuMI rate set by 5 booster batch limit, so no way to get back to curve by end of FY

- NuMI Beam delivery significantly impacted by unforseen down times

- Resin beads in water system

## Revisions to Long Term Projections

- Batch size
- Old scheme used one batch size with low “efficiency” for slip stacked batches
- Accurate but confusing
- New scheme has two explicit batch sizes
- Slip stacking to NuMI
- Originally believed we could start slip stacking after the 2006 shutdown.
- Now believe slip stacking losses will necessitate collimators, which will not be installed until 2007 shutdown
- Uptime
- Major factor in NuMI beam delivery
- Old scheme had only small variation between design and base (~81%)
- New scheme:
- NuMI “base” will be ~uptime from turn-on through shutdown (70%)
- BNB base will budget 1 unscheduled horn replacement every two years (78%)

## Revisions (cont’d)

- Post shutdown turn-on
- Historically tried to cover this by using a projection shutdown longer than actual shutdown
- Real shutdown always extended to same length
- Still looks bad
- New scheme:
- Post shutdown exponential ramp up with ( ~2 weeks)
- Cogging losses
- Old scheme did not account for the fact that cogged cycles (pbar and NuMI) lose more energy than uncogged cycles.
- Somewhat compensated by the old way we handled slip stacked batch sizes.
- Now include 20% increased energy loss for cogged cycles.

## Machine Loading

- Assumes model where slip stacking is implemented by going immediately to 2+9, but with reduced batch sizes to NuMI.
- Ultimate goal (44 week year)
- NuMI: 3.2E20 p/yr
- BNB: 1.8E20 p/yr

## Cumulative Totals