Beam diagnostics control for JPARC LINAC

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Beam diagnostics control for J-PARC LINAC

• Guobao SHEN
• J-PARC CenterJapan Atomic Energy Agency
• Mar. 2008

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Content

• Overview of J-PARC LINAC
• IOC Development
• OPI Presentation
• Beam Observation
• Performance
• Summary

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1. Overview of J-PARC LINAC

• Major Parameters
• Particles H- (negative hydrogen)
• Energy 181 MeV, The last two SDTLs are
  debunchers
• (400 MeV for ACS, 600 MeV for SCL)
• Peak current 30 mA (50 mA for 1MW at 3GeV)
• Repetition 25 Hz (additional 25 Hz for ADS
  application)
• Pulse width 0.5 msec

L3BT
181(191)MeV
(400MeV)
(600MeV )
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1. Overview of J-PARC LINAC

• Beam diagnostics

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2. IOC Development

• Hardware Interfaces of Monitor Control
• WE modules from Yokogawa
• Digitizer module for data acquisition
• WE7118 100MS/s, 14-bit resolution, 2 channels
• for BPM, FCT WSM
• WE7111 100MS/s, 8-bit resolution, 1 channel
• for SCT and BLM
• Digital switcher for phase detector
• WE7262 DIO module
• WER modules
• Home-made Wave-Endless-Recorder.
• 200MS/s, 12-bit resolution, 4 channels
• for BPM
• 10MS/s, 12-bit resolution, 4 channels
• for BLM

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2. IOC Development

• IOC for WE control
• DAQ
• By IOC directly
• IOC
• H/W Advme7501 VME-SBC (PowerPC)
• S/W OS vxWorks 5.5.1 EPICS 3.14.8.2

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2. IOC Development

• IOC for WER control
• DAQ
• Rack-mounted Server A Java based Application
  (METIS)
• IOC
• H/W Rack-mounted Server (Intel-based)
• S/W OS RHEL 4 (Nahant) EPICS 3.14.9

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3. OPI Presentation

• Beam current
• SCT waveform
• MEDM based
• Confirmed beam 1st day of 1st beam study
• Beam current
• EDM based
• High intensity beam study Confirmed beam _at_ 25mA

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3. OPI Presentation

• Beam delivery
• 1st beam observation at 30º dump (RUN3 )
• 181MeV, 5.5mA, 20µs, 2.5Hz

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3. OPI Presentation

• Beam position
• 181MeV, 25mA on May, 2007
• Waveform (MEDM)
• Orbit (JCE Based)

JCE J-PARC Commissioning Environment
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4. Beam Observation
BPM Monitor Beam Position Stability
SDTL03AX
SDTL02BX
May 24
Good position stability up to the SDTL-2 was
performed, but positions were moving after the
SDTL-3 in 0.5-1 hour cycle. We suspected a
Q-magnet rare short, higher order mode in the
cavity, etc., for this instability.
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4. Beam Observation
Reason The frame of the wire scanner is made of
ceramics. Electrons from the cavity charge up
the frame, and induced voltage steers the beam.
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4. Beam Observation
BPM Monitor Beam Position Stability
September 29
SDTL05A
After making new frame of the wire scanner, a
clear beam orbit jump was not seen.
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4. Beam Observation
BPM Monitor Beam position jitter
RUN12
Vertical
Horizontal
Last 2 BPMs in L3BT injection line
Last 2 BPMs in L3BT injection line
2nd last BPM
2nd last BPM
Last BPM
Last BPM
These 2 BPMs are 4.1 m apart.
The position jitter at the RCS injection is
around 0.2 mm (60 ?m in RMS) including the
intrinsic jitter (or noise) of the monitor system.
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Wire Scanner Typical horizontal profile
4. Beam Observation
25mA Collimator section
WS55
WS53
Slight haloobserved in the horizontal
direction.
WS59
WS57
Slight halo
Noisy
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Wire Scanner Typical horizontal profile
4. Beam Observation
25mA Collimator section
WS55
WS53
More profound halo is observed in the vertical
direction.
WS59
WS57
Noisy
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5. IOC Performance

• Resource using ratio (repetition 2.5Hz)
• CPU usage lt 40
• Memory usage 25
• Performance
• Repetition rate up to 6Hz
• Satisfy current requirement of beam commissioning
  (2.55Hz)
• Achieved WE hardware limit

During Beam commissioning
CPU Usage
Memory Usage
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6. Summary

• Beam Diagnostics Control for J-PARC LINAC
• Two type hardware interfaces are employed
• Commercial hardware WE from Yokogawa
• Module based, Compact digitizer
• Home-made digitizer WER
• EPICS based
• IOC
• EPICS R3.14.8.2vxWorks5.5.1
• EPICS R3.14.9RHEL 4
• OPI
• MEDM, EDM, JCE App
• Effective beam commissioning
• with the support of diagnostics control
• The control of beam diagnostics proved their
  usefulness in the beam status observation, and
  the beam commissioning