Beam diagnostics control for J-PARC LINAC

Guobao SHEN

J-PARC CenterJapan Atomic Energy Agency

Mar. 2008

Mar. 2008 Beam diagnostics control for J-PARC LINAC 2

Content

Overview of J-PARC LINAC

IOC Development

OPI Presentation

Beam Observation

Performance

Summary

Mar. 2008 Beam diagnostics control for J-PARC LINAC 3

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

181(191)MeV (400MeV) (600MeV )

L3BT

1. Overview of J-PARC LINAC

Mar. 2008 Beam diagnostics control for J-PARC LINAC 4

Beam diagnostics

Device Types Purpose Total

SCT (Slow Current Transformer) Beam Current 38

FCT (Fast Current Transformer) Beam Phase/Energy 61

Digital Switcher for phase detector Dynamic Range Change 21

BPM (Beam Position Monitor) Beam Orbit 102

WSM (Wire Scanner Monitor) Beam Size/Profile 36

BLM (Beam Loss Monitor) Beam Loss 58

1. Overview of J-PARC LINAC

Mar. 2008 Beam diagnostics control for J-PARC LINAC 5

2. IOC Development

Hardware Interfaces of Monitor ControlWE 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 moduleWER modules

Home-made Wave-Endless-Recorder. 200MS/s, 12-bit resolution, 4 channels

for BPM 10MS/s, 12-bit resolution, 4 channels

for BLM

Mar. 2008 Beam diagnostics control for J-PARC LINAC 6

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

Mar. 2008 Beam diagnostics control for J-PARC LINAC 7

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

Mar. 2008 Beam diagnostics control for J-PARC LINAC 8

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 @ 25mA

Mar. 2008 Beam diagnostics control for J-PARC LINAC 9

3. OPI Presentation

Beam delivery1st beam observation at 30º dump (RUN3 )

181MeV, 5.5mA, 20μs, 2.5Hz

SCT

SCT Waveform2mA

40s

30º dump

0º dump

beam

Bendmagnets

Mar. 2008 Beam diagnostics control for J-PARC LINAC 10

3. OPI Presentation

Beam position181MeV, 25mA

on May, 2007

Waveform (MEDM)

Orbit (JCE Based)

JCE: J-PARC Commissioning Environment

Mar. 2008 Beam diagnostics control for J-PARC LINAC 11

May 24SDTL02BX SDTL03AX

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.

4. Beam ObservationBPM Monitor: Beam Position Stability

Mar. 2008 Beam diagnostics control for J-PARC LINAC 12

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.

4. Beam Observation

Mar. 2008 Beam diagnostics control for J-PARC LINAC 13

After making new frame of the wire scanner, a clear beam orbit jump was not seen.

SDTL05A

4. Beam Observation

September 29

BPM Monitor: Beam Position Stability

Mar. 2008 Beam diagnostics control for J-PARC LINAC 14

Horizontal

Last BPM

2nd last BPM

Vertical

Last BPM

2nd last BPM

Last 2 BPM’s in L3BTinjection line

Last 2 BPM’s in L3BTinjection line

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.

RUN12

These 2 BPM’s are 4.1 m apart.

BPM Monitor: Beam position jitter

4. Beam Observation

Mar. 2008 Beam diagnostics control for J-PARC LINAC 15

Wire Scanner: Typical horizontal profile

WS53 WS55

WS57 WS59

Noisy

25mACollimator section

Slight halo

Slight haloobserved in the horizontal direction.

4. Beam Observation

Mar. 2008 Beam diagnostics control for J-PARC LINAC 16

WS53 WS55

WS57 WS59

Noisy

25mACollimator section

More profound halo is observed in the vertical direction.

4. Beam ObservationWire Scanner: Typical horizontal profile

Mar. 2008 Beam diagnostics control for J-PARC LINAC 17

5. IOC Performance Resource using ratio (repetition: 2.5Hz)

CPU usage: < 40% Memory usage: ~ 25%

Performance Repetition rate: up to 6Hz

Satisfy current requirement of beam commissioning (2.5~5Hz) Achieved WE hardware limit

During Beam commissioning

CPU Usage

Memory Usage

Mar. 2008 Beam diagnostics control for J-PARC LINAC 18

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 R3.14.8.2+vxWorks5.5.1 EPICS R3.14.9+RHEL 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