# Presentation: 498633

## AcceleratorComplex Performance

- Ioanis Kourbanis
- Fermilab Accelerator Division

## Overview of Accelerator Complex

## Overview of MI, Pbar Source and Neutrino Beams

## Goals for FY05

- Install electron Cooling in the Recycler during the Fall ’04 shutdown and demonstrate cooling of antiprotons by the end of FY05.
- Increase pbar production aperture by 25%.
- Run Slip Stacking at 8E12 protons/pulse every 2 sec.
- Stack at small stacks with a rate of 24E10 Pbars/hr.
- Run the complex in Combined Shots operations.
- Integrate 470 pb in 34 weeks.
- Finish NuMI Installation and commission NuMI beam by early Spring.
-  Change the MiniBoooNE horn.

## Schematic Layout of the Electron Cooling System

## Electron Cooling

- The maximum antiproton stack size in the Recycler is limited by
- Stacking Rate
- Longitudinal cooling in the  Recycler
- Longitudinal stochastic cooling of 8 GeV antiprotons in the Recycler is to be replaced by Electron Cooling
- Electron beam: 4.34 MeV – 0.5 Amps DC – 200rad beam spread – 99% recirculation efficiency
- Installation of e-cool equipment in MI-31 and the Recycler tunnel complete
- Commissioning of electron cooling in progress
- Electron beam circulated in cooling section
- Commissioning due to be completed by September 2005

**Pelletron**

## Combined Shots

- Extracting pbars from both the Accumulator and Recycler for the same store
- Luminosity enhancement – larger amount of antiprotons for smaller emittances
- Accumulator stack size limited to <200 mA
- Stacking Rate
- Transverse emittance vs Stack Size

## Accumulator to Recycler Antiproton Transfers

- Transfers between the Accumulator to the Recycler take about 1 hour to accomplish
- Transfers frequency every 6-8 hours
- To realize the full potential of electron cooling, in the Recycler, this time needs to be reduced to less than 15 minutes
- Adopt a philosophy of being willing to lose a pbar transfer occasionally
- Transfers frequency faster than every 2 hours

## Antiproton Production – Slip Stacking

- Slip Stacking is the process of combining two Booster batches at injection into in the Main Injector to effectively double the amount of protons on the antiproton production target

## Antiproton Production – Slip Stacking

## Antiproton Aperture - Pbar Production

- The measured aperture of the initial stages of the antiproton production chain is about 70% of the available physical aperture.
- An aggressive beam-based alignment program is under development to bring the measured aperture to the physical aperture.
- Would increase the stacking rate by a factor of 2
- The beam based alignment scheme consists of 5 major components
- Independent control of the quad gradients (done)
- Beam position measurement system to measure orbit distortion due to varying quad gradients (in- progress)
- Orbit control devices to center the beam through the quads (done)
- Moveable control of tight apertures (stochastic cooling arrays) (in progress)
- Loss monitor system to measure losses at tight apertures (done)
- Most of the recent focus has been to complete the instrumentation upgrade
- Extremely small beam currents ~10Amps
- The goal for this year is to increase the aperture for each plan to 78% of the available physical aperture which would result in a 25% increase in antiproton production rate

- Old

- New

## Pbar Production for Run II

**Most Pbars stacked in one Week:1334E10 May 9 2005**
**Most Pbars send to Recycler in one Week: 672E10 April 25 2005**

## Pbar Stacking Performance for Run II

**Most Pbars accumulated in one hour: 16.2E10, March 24 2005**
**Highest average stacking rate for one week 12E10, April 4 2004**

## Tevatron Helical Orbit Separation

- More separators
- Higher separator voltage
- Separator R&D
- Different separator configuration
- Polarity switches

## Tevatron Instrumentation

- Tevatron BPM Project
- Joint CD/AD effort
- A major success
- Project making very good progress though completion date has slipped by a few months
- An order of magnitude improvement in proton position measurements and new for pbars
- Position resolutions in the range of ~10 -25 
- Will be extremely useful in understanding beams and lattice measurements.
- Can see synchrotron and betatron lines, quadrupole oscillations, H-V coupling, etc.
- 85% installed
- ~ 50% connected/ commissioned
- New Beam loss monitor system
- New Ion Profile Monitor

## Integrated Luminosity

## Luminosity History

- Luminosity increase is mostly due to:
- Better performance of the injector chain
- Introduction of the Recycler into operations
- Alignment of the Tevatron
- Decision to “run” the Collider
- Rigorous approach to attacking operational problems
- De-emphasis of long periods of dedicated machine studies

## MiniBooNE Running and Proton Source Performance

- Successfully replaced the failed MiniBooNE horn.
- Proton Source had Record throughput for MiniBoone
-  8.0x1016protons/hour
- Delivered a over 5x1020protons in under three years of running
- Proton Source is routinely delivering 7E16p/hr.
- Cogging for Slip Stacking and NuMI is working well
- Working on improving rf reliability and beam quality for slip stacking.

## MiniBooNE Beam Performance

## Proton Source Performance

## SY120

- Established a Mixed Mode for SY120 with slip stacking for pbar production (2.8 sec long cycle with 0.65 sec spill)
- A factor of 7 more spill sec than originally allocated
- After NuMi was commissioned we switched to one 6 sec cycle every 2 min with dedicated SY120 beam (4 sec spill).
- Maximize the spill sec while maintaining a reasonable length of MI flattop.
- The average number of pulses per week was reduced by a factor of 12.5 but the number of spill sec was only reduced by a factor 1.9.
- Allows us to inject additional Booster batches
- Work on improving beam quality continues.

## NuMI Extraction Kickers

**NuMI  Kickers allow up to 6 Booster Batches to be extracted to NuMI**

## NuMI Running

- First beam on target on Dec 4, 2004. (Beam extracted out of MI on the first pulse!).
- NuMI running became operational on March 16 (mixed mode cycles).
- After target fixes we resumed NuMI high Intensity running on May 5.
- Currently we are running NuMI with 1.5E13P/pulse and with the pbar stacking rep. rate.
- We are currently working on increasing the NuMI per pulse Intensity and running Dedicated NuMI cycles during shot set-ups.
- We eventually plan to run at a constant rate of 0.5 Hz.

## MI Mixed Mode Running

-  **MI Beam Intensity~2.3E13p**

**NuMI Beam Intensity~1.45E13p**

**MI losses~2KJ**

**NUMI Beamline Losses**

**MI Beam Intensity**

**105 Loss Monitor**

**MI Losses (KJ)**

## NuMI Beam History for Last Week

## NuMI Progress

## NuMI Beam

## MI Mixed Mode Losses

- During Slip Stacking a small fraction of the beam leaks out of the rf buckets and is recaptured in buckets adjacent to the 84 buckets extracted to the pbar target.
- In the NuMI and stacking mixed mode cycles, most of this beam is kicked by the MI injection kicker and is lost  at the 104 location.

- Bunches to Pbar Target

**MI Beam at 120 GeV (Slip Stacking only)**

**Beam that leaked out during Slip Stacking**

## MI Mixed Mode Losses

- In MI we have implemented barrier buckets and our digital bunch by bunch dampers to reduced this loss.
- So far we have managed to reduced the loss at 104 by a factor of  6-7 (as measured by our loss monitors).
- Work is in progress in Booster to improve bunch rotations and further reduce this loss.

- Loss monitor at 105 (Blue trace) before(left) and after(right) anti-damping.

## Summary

- We are on track to meet and exceed our integrated luminosity goal.
- Recycler is operational (Combined shots)
- TeV and Proton Source are performing very well
- The Run II Upgrades are on track to provide over 8fb-1 by 2009
- Electron cooling is progressing well
- Slip Stacking is operational
- The major challenge left in Run II is the increasing the antiproton production rate
- AP2- Debuncher aperture upgrade
- Debuncher to accumulator transfers
- Stacktail Momentum cooling uprade
- Rapid transfers between the Accumulator and Recycler
- NuMI beam has been commissioned.
- Supporting two neutrino experiments and the Collider Program presents a challenge to both the Proton Source and the Main Injector.
- Booster has to reliably provide high quality beam at high intensity and rep rate
- Monitoring and controlling losses in MI