# Presentation: 416064

## MiniBooNE Beam Liasons

*Eric Prebys*
- FNAL Beams Division

## The Facts

- Right now, the Booster is delivering about 1/5 of what MiniBooNE wants.
- This is primarily limited by beam losses in the tunnel.
- In 2005 (?), NuMI will come up wanting about half the protons of MiniBooNE – hopefully ramping up to about the same number.
- -> To run the two together is a factor of 10 over what is now being delivered.
- There is no clear plan to do this.
- In addition to improving the peak running of the Booster, it’s very important to work to maintain extremely consistent operation to get the most protons we can.

## How Can Experimenters Reasonably Help?(this is a question)

- Help tune the Booster?
- Must go to formal operator training.
- ~75% commitment for at least 6 months.
- Maybe better to pressure lab to hire dedicated operator.
- Help with studies?
- Need to learn accelerator physics (just missed USPAS).
- Need to learn something about controls, but maybe not formal operator training.
- ~75% commitment for at least 6 months.
- Probably have enough people already.
- Help “keep an eye” on things?
- Must get reasonably familiar with the controls system.
- Significant, but not total, commitment.
- Need to establish a well defined, and mutually acceptable, relationship with operations.

## Modes of Operation

- Run II Life Revolves around the antiproton stack. Stacking typically occurs about 2/3 of the time.

- Something broken (usually NOT the proton source)

- Stacking

- Shot Setup

## Modes of Operation vis-à-vis MiniBooNE 

- Stacking
- Requires: Proton Source, Main Injector, Debuncher-Accumulator.
- Requires “significant” protons.
- A train of MiniBooNE batches occur every 1.5-2.0 s, at 15 Hz following stack batch.
- Stable operation.
- Can tolerate “reasonable” number of trips.
- Shot Setup
- Requires: Everything
- No significant proton requirement
- Configuration changes rapidly, and MiniBooNE timeline will have to accommodate.
- Probably less tolerance for trips.
- Studies
- Requires: Whatever’s up
- Generally no significant proton requirement
- Configuration can change even more rapidly.

## The Road to MiniBooNE

**H****-**

**I****-**

**Preac**25 keV 750 keV

- Old 200 MHz Linac750 keV 116 MeV

- New 800 MHz Linac116 MeV 400 MeV

- Debuncher

- ORBUMP Injection

- Booster (20000 turns) 400 MeV 8 GeV

- Main Injector

- MiniBooNE Horn

- Switch Magnet

## Stumbling Blocks in the Road (injection)

-  Ion Source – current fluctuation can screw up linac beam load compensation  off momentum beam.
-  Old linac – Old power amplifier tubes very temperamental  off momentum beam, slewing momentum, oscillating momentum.
- New linac – New klystrons more robust than old PA’s, but still sometimes phase drifts (or intentional changes)  off momentum beam, slewing momentum.
- 400 MeV transfer line – not well understood, not regularly tuned  beta mismatch at injection.
- Debuncher – too much “black magic”.  Often incorrectly used to compensate for off-momentum linac beam.

- All of these can lead to capture problems, early losses, and/or beta mismatch (which could lead to losses throughout cycle).

## Monitoring Injected Beam

- We now (after 30 years!!) measure the relative phase of the beam at two point to get the velocity (energy), and also the phase relative to the debuncher.
- Presently available on the “chopper scope”, but soon (now??) becoming an official device.
- Most of the problems mentioned will show up on this monitor, but crew is only now becoming conditioned to use it.
- This is highly correlated with a variety of “weird behavior” which was formerly dealt with by adjusting the capture parameters of the booster!

## Stumbling Blocks in the Road (Booster)

-  **Capture losses:** injections problems discussed, RF paraphasing, RF feedback sample timing problems.
-  **Steady losses:** orbit misalignment, scraping, RF feedback problems. Quadrupole and sextupole ramp adjustments.
-  **Transition losses:** tune/chromaticity problems.  Adjust quadrupole and sextupole ramps.
-  **Post transition losses:** coupled bunch instabilities.  Check state of longitudinal dampers.
**Extraction losses:**  notch position, orbit control at extraction septa.
**Mysterious losses (buzz 1, buzz2):** talk to Ray Tomlin

*(These are listed as symptom: possible causes)*

## Typical Booster Cycle

- Various Injected Intensities

- Transition

- Intensity (E12)

- Energy Lost (KJ)

- Time (s)

## Booster Losses (Normalized to Trip Point)

- BRF11: 200 mR/hr @ 1ft

- BRF15: 300 mR/hr @ 1ft