# Presentation: 331078

## Accelerator Operations  and Performance

- Ron Moore
- FRA Visiting Committee Review
- April 20/21 2007

## Accelerator Operations Overview

- Collider Run 2
- Tevatron 36×36 proton-pbar collisions to CDF and D0
- Design goal = 8 fb-1 by end FY09
- Delivered > 2.5 fb-1 so far
- Pbar production is key factor for increasing luminosity
- Neutrino Program
- MiniBoone: 8 GeV protons from Booster
- > 8.5 E20 protons-on-target  (neutrino/antineutrino modes combined)
- NuMI: 120 GeV protons from Main Injector (MI)
- Approaching 3 E20 protons-on-target
- Proton Plan & beyond: increase proton beam power
- Switchyard 120 – Meson Test Beam Facility (MTBF)
- Deliver 120 GeV protons and 1-64 GeV secondaries π, K, p, e, μ
- Run in parallel with Run 2 and neutrino program
- 1 slow/fast spill from MI every 60 seconds ~12 hr/day

## Tevatron Run 2 Delivered Luminosity

*Through April 17*

*> 1 fb**-1** since June 2006*

## FY07 Tevatron Performance

*through April 17*

- D32-5 failure
- feeder 46B fault

- E4 cryo vacuum

- A18 vacuum leak

## Record Comparison Before/After 2006 Shutdown

- Peak luminosity increased 62% (180 → 292 μb-1/s)      1 μb-1/s = 1030 cm-2 s-1
- Weekly integrated luminosity increased ~75% (25 pb-1 → 45 pb-1)
- Monthly integrated luminosity increased ~95% (85 pb-1 → 167 pb-1)
- One hour antiproton stacking record -- 23.1 E10/hr
- Antiproton accumulation for one week -- 2800 E10

## Tevatron Highlights

- Reliability
- Replaced all ≈1200 LHe Kautzky valves  (cause of 2 FY06 dipole failures)
- Modifying quench protection system to allow faster beam aborts
- Cog pbars out of abort gap for acceleration – prevent needless quenches
- More pbars with smaller emittances to HEP
- Thanks to Pbar Source and Recycler  (later slide)
- More protons to HEP
- Injecting ≈10% more protons
- Better lifetime @ 150 GeV from new helical orbit, reduced beam-beam
- Improved luminosity lifetime
- Additional separators increase separation  (20% at nearest parasitic crossings upstream of interaction points)
- Beam-beam effects reduced – performance agrees better with model neglecting beam-beam

## Comparing to Model without Beam-Beam Effects

- After shutdown, luminosity evolution for similar stores agrees better to model _without_ beam-beam effects
- Most pbars lost during HEP are burned in luminosity  (good!)
- Protons suffering from head-on beam-beam due to brighter pbars
- Limited tune space

*V. Lebedev*

- Store 4581
- Linit = 170

- Store 4859
- Linit = 168

- hr

- hr

## Looking Ahead

- Implement 2nd order chromaticity correction @ low β
- Simulations show improved lifetimes during HEP
- Studies in progress
- Also prerequisite to pursue possible new working point near 1⁄2 integer
- Pursue other minor improvements (few % each) – they all add up!
- Scrape (higher intensity) protons @ 150 GeV
- Investigating new cogging between pbar injections
- Reduce beam-beam effects by changing locations of long-range crossings
- Use TELs (electron lenses) on protons for beam-beam compensation
- Raise tunes of individual bunches away from 7/12 resonance to improve lifetime
- More reliable (bunch-by-bunch) tune measurements
- Better helices, improved transfer line matching, faster shot-setups, etc.

## Run 2 Weekly Antiproton Accumulation

- Weekly Accumulated Pbars   [1010]

- June 06

## Antiproton Improvements

- Antiprotons delivered to Tevatron up 45%
- Accumulator stacktail gain correction - 12%
- Fast Accumulator-to-Recycler transfers - 10%
- Recycler to Tevatron transfer efficiency - 6%
- Misc. (reliability, etc.) - 11%
- Other factors
- Lithium lens -- increasing gradient
- Focus more pbars into AP2 line leading to Debuncher/Accumulator
- Lebedev Model to understand stacktail -- good match to data
- Stacktail cooling in Accumulator identified as major bottleneck
- New Recycler working point
- Reduce impact of space charge tune shift; smaller emittances
- Pbar bunch intensity leveling in Recycler
- Uses RF feedforward system to reduce bunch-to-bunch variations
- Helpful for Tevatron and experiments’ trigger/DAQ systems

## Reducing Time for Pbar Transfers to Recycler

- Stacking-to-Stacking Time (min)

## Collider Plan

- Increase pbar stacking rate
- Optimize new stacktail equalizer
- Begin working on stacktail equalizer #2
- New Accumulator lattice
- Slowly increase stash size in the Recycler
- Implement 2nd order chromaticity correction in Tevatron
- Optimize peak vs integrated luminosity with experiments
- Approaching design 320 μb-1/s peak luminosity
- Continue to work on reliability in all machines

## Integrated Luminosity Projections

- We’re in this area now
- 2.6 fb-1
- ≈23 mA/hr
- April ‘07

- We’re in this area now
- 2.6 fb-1
- ≈23 mA/hr
- April ‘07

## Projecting Luminosity

- Updated model based on current conditions and using various operational scenarios   (V. Papadimitriou)
- Pbar stacking rate, store lengths, lifetimes, transfer efficiencies, etc
- Vetted by reproducing FY 2006 numbers
- Only ≈1 fb-1 spread among various scenarios
- Based on current pbar stacking rate, on track to deliver   5.5-6.5 fb-1 total
- Likely need increased pbar stacking rates to go higher
- Goal is to maximize _integrated_ luminosity on tape

## Luminosity Projections with Updated Model Scenarios

***updated model scenarios 1 to 4***

## Neutrino Program

- MiniBoone
- Booster improvements during shutdown allowing higher throughput - exceeding design proton delivery rate
- Resumed run after 14 week shutdown for absorber repairs
- NuMI
- FY07 already best year:   >1.2 E20 POT delivered
- Improvements in slip-stacking
- 2+5 mode operational
- 180-200 kW beam power with pbar production
- 250-300 kW running NuMI-only
- 2+9 mode being developed for FY08 running
- Single pulse record > 4 E13
- Want to push pbar production cycle 2.4 → 2.2 sec
- Already @ 2.2 sec during pbar shots to Recycler

## NuMI Delivered Protons-on-Target

*> 1.5 10**20** POT  since June 2006*

*through April 17*

## FY07 NuMI Delivered Protons

*TeV cryo problem in F-sector*

*NuMI magnet*
*H**2**O leak*

*close to design delivery rate despite longer cycle time  (2.4  vs. 2.2 sec)*

## Multi-batch Slip Stacking in MI

- Record:
- 4.05 1013 protons  (NuMI-only cycle)
- 90% efficiency
- Goal:
- 4.4 1013 protons to 120 GeV  (NuMI + pbar)
- 95% efficiency

**11 batches to NuMI**

**11 ********s (1 revolution)**

## Staged Neutrino Program

- Proton Plan
- MI RF improvements and operational loading initiatives increase NuMI intensity to 4-5 ×1013 protons per 2.2 second cycle (≈3×1020 prot/yr)
- Ultimately 320 kW to NuMI  (400 kW when not running pbar source)
- Runs through end of collider program
- ANU (“Accelerator NuMI Upgrades”, combined with NOvA as per DOE)
- Use Recycler as pre-loader to save time injecting into MI
- ~700 kW to NOvA
- Presently being formalized and baselined
- SNuMI (formerly “SNuMI II”)
- Momentum-stack protons in Accumulator → boxcar stacking in Recycler
- Ultimately ~1.2 MW to NuMI
- Still in early conceptual stage
- HINS (formerly “Proton Driver”)
- New 8 GeV proton linac to Main Injector, exploit synergy with ILC
- ≥2 MW to NuMI
- Not part of our official planning at this point

## Significant Elements of Proton Plan

- Linac
- Stockpile two year supply 200 MHz power amplifier tubes (7835’s)
- 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  (48 packages)
- Install half in 2007 shutdown, other half in 2008
- Main Injector
- Replace 7 quadrupoles with larger aperture to reduce injection/extraction losses
- Develop multi-batch and multi-batch slip-stacked operation
- Design and install collimation system for MI-8 line and in the MI ring (2007)
- Modify injection kickers to allow multi-batch slip stacked operation
- Characterize and improve RF system to support high intensity operation

- Green = complete

## Accelerator Division Injuries by Fiscal Year

## Highlights of AD Safety Plan

- Grass Roots Safety Committee
- Improved feedback mechanism for employees
- Quarterly ES&H Newsletter
- Focus on maintaining areas

## Summary

- Run II delivered luminosity has made dramatic progress over the past year
- Tevatron performance is still improving
- Antiproton stacking rate continues to improve
- Projections indicate good chance to reach luminosity goal
- Neutrino program benefiting from advances in Booster and Main Injector
- Meeting or exceeding NuMI/MiniBoone proton rates
- Implementing remaining Proton Plan upgrades
- Additional staged plans under development
- Continue efforts on operating the complex safely

## Backup Slides

## Model Parameters for FY06 Luminosity 

-  Luminosity Density @ 100 x 1010  62.5 b-1 / sec
-  Luminosity Density @ 300 x 1010  180.4 b-1 / sec
-  Init Tevatron Lifetime @ 80 b-1/sec 7.7 hours
-  Init Tevatron Lifetime @ 160 b-1/sec 6.9 hours
-  HEP store hours per week 98 hours
-  Acc-Rec Transfer Efficiency @ 0x1010  86%
-  Acc-Rec Transfer Efficiency @ 300x1010 86%
-  Acc-Rec transfer time 0.5 hours
-  Recycler lifetime 500 hours

-  Recycler mining efficiency 97%
-  Initial stack stack rate 17.5x1010/hour
-  Half rate stack size 150x1010
-  Maximum stack size 320x1010
-  Timeline Utilization Factor 75%
-  Accumulator leftover factor 15%

- With the above inputs we should have
- expected ~ 19 pb-1/week in FY06 for
- a total of ~670 pb-1

- This is to be compared with 656 pb-1
- delivered in FY06

- Model Parameters for FY06 Luminosity

*Parameters varied in projecting integrated luminosity...*

## Limits to Proton Intensity

- Total proton rate from Proton Source (Linac+Booster):
- Booster batch size
- ~4-5E12 protons/batch, depending on beam quality required.
- Booster repetition rate
- 15 Hz instantaneous
- Currently ~9 Hz, limited by RF system.
- 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 (4.5-5.5E13)
- Beam stability (RF issues)
- Beam loss concerns
- Cycle time:
- 1.4s + loading time (1/15s per booster batch)

- Historically our biggest worry

- Critical path for NuMI/MINOS