BNL Diagnostics Meeting

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BNL Diagnostics Meeting
BNL Diagnostics Meeting Feb. 5-6, 2004 Held at
BNL Mike Plum
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The HEBT, Ring, and RTBT
Ring Service Building
Ring
HEBT
RTBT
HEBT Service Building
RTBT Service Building
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HEBT/Ring/RTBT Commissioning Schedule
CD-4 deadline 1/Jun/06
HEBT/Ring/RTBT, to extr. dump 6/Jul 18/Nov/05
Jan/07
Jan/06
Jan/05
Linac, to linac dump 11/Mar 31/May/05
RTBT, to target 1/Feb 28/Feb/06
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High level commissioning plan

• HEBT beam line up to arc, then on to linac dump,
  commissioned as part of linac commissioning
  (start 11/Mar/05 31/May/05).
• Beam current limited (by linac dump) to 7.5 kW
  avg. One full pulse (24 kJ) at very low rep rates
  is also OK.
• Start with low current beam (1 - 4 Hz, 1 - 100
  us) (note 1 ea. 38 mA, 690 ns minipulse 26 J,
  and1Hz, 100 us, 26 mA avg (38 mA chopped) 2.4
  kW)
• Should be able to use single mini pulse beam to
  steer beam to dump.
• Steer beam through collimators using BPMs and
  loss monitors.
• Check that BPMs, BLMs, BCMs, WSs all
  functioning.
• Check beam emittance and match to HEBT using the
  four wire scanners at the beginning of the HEBT
  (WS01-04).

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High level commissioning plan (cont.)

• Commission up to ring extraction dump (6/Jul/05
  18/Nov/05).
• First commission HEBT up to injection dump.
• Current limit to injection dump is about 150 uA.
• Start with low current beam (1 - 4 Hz, 1 - 100
  us).
• Should be able to use single mini pulse beam to
  steer beam to dump.
• Check that BPMs, BLMs, BCMs, WSs all
  functioning.
• Check HEBT optics Beam parameters at foil
  (position, emittance, Twiss parameters,
  achromat) beam stability at foil.
• Measure beam emittance and Twiss parameters using
  WS20-23, WS32). Extrapolate to ring and verify
  correct. Adjust if not.
• Check beam position and position stability at
  foil, using HEBT/IDump BPMs upstream and
  downstream of foil, and phosphor screen / video.
• Measure dispersion in HEBT arc, using BPMs and
  varying beam energy. At same time check for
  achromat at end of arc and at stripper foil,
  using BPMs and foil video.
• May want to check halo scrapers. Insert until see
  beam loss increase.

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High level commissioning plan (cont.)

• Next commission ring.
• Current limit to extraction dump is 7.5 uA avg.
  Not necessary to extract beam if power is less
  than a few kW (2 kW/collimator).
• Verify correct beam parameters at stripper foil
  using WS20-23, WS32, foil video, and BPMs.
• Verify stripper foils are in place and in good
  shape using foil video cameras.
• Single shot injection into ring, 1 4 Hz. Bump
  magnets off rf off trim, sextupole, octupole
  magnets off, scrapers at out limits.
• Correct closed orbit using BPM system.
• Measure betatron tune and position/angle of
  injected beam at foil using BPM system in ring.
• Very important Need BPM system that works well
  with single shot injection (20 mA pk, 500 ns,
  1 mm resolution). Note Model calculations
  predict that 402.5 MHz structure will dissolve
  after about 10 turns. Need good baseband system.

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High level commissioning plan (cont.)

• Ring commissioning (cont.)
• Measure ring revolution frequency and check MEBT
  chopper period. Necessary for multi-turn
  injection. Use BPM and/or WCM.
• Next commission up to extraction dump.
• Keep beam current low 1 to 10 turn
  accumulation, 1 4 Hz.
• Extract beam at about 50 us from start of
  injection, before beam has time to debunch.
• May need to flat-top injection bump magnets to
  get small beam size.
• Steer beam using BLMs and BPMs.
• Check for good beam transport to extraction dump.
• Check RTBT BLMs, BCMs, BPMs, WSs.

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High level commissioning plan (cont.)

• Commission up to ring extraction dump (cont.)
• Ramp beam current to 1013 ppp (CD-4 requirement).
• To get 1013 ppp, need 75 turns at 38 mA peak, but
  OK to inject for longer at lower peak currents
  (15 - 20 mA)
• 1013 ppp at 1 Hz 1.6 kW. Limit is 7.5 kW avg to
  ext. dump.
• Check injection bump magnet system using BPMs
  and IPM.
• Check ring rf system using BCM and wall current
  monitor.
• Check that beam losses remain below operational
  limits.
• This is the minimum needed for CD-4.

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High level commissioning plan (cont.)

• Commission RTBT to target (1/Feb 28/Feb/06).
• Verify 1013 ppp to extraction dump.
• Reduce beam current to 1 10 turns accumulation,
  1 Hz.
• Steer beam to target.
• Verify beam size and position on target, using
  harp and halo monitor (thermocouples downstream
  of proton beam window).
• We are working on a temporary phosphor screen
  that can be used to qualify and tune up the beam
  at the target.
• Check RTBT BLMs, BCMs, BPMs, WSs.
• Ramp beam current up to 1 Hz, 1013 ppp, and
  declare success in meeting CD-4!

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Ramp up to high power operations

• After CD-4 need to ramp up to high power
  operations.
• 3 kW in 06, 50 150 kW in 07, 300 800 kW in
  08, 1200 1400 kW in 09.
• Primary goals run ring with acceptable beam loss
  (1 W/m of uncontrolled loss) and deliver beam to
  target with correct size and position.
• Tools needed to achieve these goals
• Diagnostics to measure beam loss, beam lifetime.
• Fast and slow BLM system.

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Ramp up to high power operations (cont.)

• Diagnostics to measure lattice functions
  (betatron functions, dispersion functions,
  chromaticity). Needed to fine-tune ring lattice.
• BPM system, single shot and multi-turn
  accumulation.
• Kicker system would allow more accurate
  measurements and lattice function measurements at
  higher beam powers.
• Measure orbit response matrix (closed orbit,
  phase, tune, betatron amplitude vs. steering
  magnet and quad magnet variation).
• With 200 turns can get good measurement of phase
  advance, used to verify/optimize quad settings.

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Ramp up to high power operations (cont.)

• Diagnostics to measure chromaticity ( magnets to
  control it). Needed to adjust chromaticity toward
  zero.
• BPM system.
• Kicker system would allow more accurate
  measurements at higher beam powers.
• Measure tune vs. injection energy.
• Diagnostics to measure beam energy.
• Fast BCM and/or wall current monitor.
• Measure revolution period for a few hundred turns
  after end of injection, with rf off.
• Diagnostics to measure beam halo.
• Halo scrapers.
• Beam losses caused by halo will likely be the
  ground on which we spend most of our time
  fighting.

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Ramp up to high power operations (cont.)

• Diagnostics to measure structure resonances (
  magnets to control them).
• Loss monitor system.
• BPM system (and kicker system preferred).
• Measure beam loss (and tune) as move
  low-intensity tune across resonance line.
• Diagnostics to measure longitudinal profile.
• Needed to verify MEBT chopper frequency.
• Needed to set up 1st harmonic rf system and 2nd
  harmonic rf.
• Fast BCM and/or wall current monitor.
• Tune phase to get symmetric bunch shape.
• Tune amplitude to keep gap clear of beam.

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Ramp up to high power operations (cont.)

• Diagnostics to measure evolution of beam profile.
• WS in extraction line, or non-intercepting beam
  profile monitor, e.g. IPM (preferred).
• Verify that injection painting is working as
  planned.
• Diagnostics to measure coherent space charge tune
  shift.
• Coherent tune kicker.
• Measure tune as a function of beam intensity.
• Diagnostics to measure beam in gap.
• Halo scrapers BIG kicker.
• Diagnostics needed to address electron cloud
  issues.
• Electron probes.
• Wide bandwidth BPM.

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Ramp up to high power operations (cont.)

• Diagnostics to estimate incoherent tune, tune
  spread.
• 50 MHz dipole kicker/pickup.
• Quadrupole kicker/pickup.
• Diagnostics to measure beam transfer function
• 50 MHz dipole kicer/pickup.

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HEBT/Ring/RTBT diagnostics risk table
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HEBT/Ring/RTBT diagnostics risk table (cont.)
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HEBT/Ring/RTBT diagnostics risk table (cont.)
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Conclusion

• Minimal set of diagnostics needed to reach CD-4
• BPM, BCM, BLM, WS, foil video.
• Diagnostics that would reduce the risk associated
  with meeting CD-4
• Coherent tune, IPM, WCM.
• Diagnostics that would reduce the risk associated
  with achieving high power operations
• 50 MHz dipole kicker pickup, quadrupole kicker
  pickup, electron probe, halo scraper/detector,
  beam-in-gap kicker, wideband BPM.

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HEBT
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Ring
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RTBT
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