beam instrumentation performance and plans · 2 managed by ut-battelle for the u.s. department of...

Beam Instrumentation

Performance and Plans

Alexander Aleksandrov

Beam Instrumentation Group Leader

February 3, 2010

2 Managed by UT-Battellefor the U.S. Department of Energy Presentation_name

SNS Beam Instrumentation Systems are

Numerous and Diverse

RTBT17 Position

26 Loss

4 Current

1 Harp

3 FBLM

1 RTBT Video

CCL/SCL Transition

2 Position and Phase

1 Wire

1 Loss

RING44 Position

54 Loss

1 Current

12 FBLM

2 Video

2 Electron Profile Scanner

2 Transverse feedback system (analog)

SCL32 Position and Phase

32 Loss

8 Laser Wire

24 Neutron Detectors

HEBT29 Position and Phase

26 BLM,

3 FBLM

4 Current

2 BSMs

1 Laser emittance sys

IDump2 Position

1 Wire

6 BLM

2 IDump Video

EDump1 Current

4 Loss

1 Wire

LDump6 Loss

6 Position

1 Wire

CCL10 Position and Phase

8 Wires

8 Loss

1 Faraday Cup

-1 Current (removed)

4 BSMs

10 Neutral Detectors

MEBT6 Position and Phase

2 Current

5 Wires

1 CHUMPS

1 Emittance

DTL10 Position and Phase

5 Wire

4 Loss

5 Faraday Cup

6 Current

18 Neutron Detectors


Beam Instrumentation Performance and PlansFebruary 22-24, 2009

Outline

• Diagnostics downtime

• New Systems

• Overview of performance improvements upgrades and development progress

– SCL Laser Wire

– Wire Scanners

– Ring Transverse Feedback system

– Laser Stripping Experiment


Beam instrumentation-related downtime

The old VME BLM IOC processing power was insufficient to perform all desired BLM

functionality. This necessitated partial functionality being distributed to a separate Soft

IOC (IOC without instrumentation hardware).

BLM IOC CPU hardware upgrades have since made this unnecessary.

The Soft IOC functionality has now been rolled back into the VME IOC in order

to reduce system complexity and increase both maintainability and reliability.

• 12 hours for last year

• Mainly related to BLM software upgrade

Soft IOC (Linux PC)

BLM IOC (VME)

Accelerator Network

BLM Detectors

BLM IOC (VME)

Accelerator Network

BLM Detectors

upgrade



New Systems

• 8 HEBT BPMs in operation

• 4 HEBT scrapers read-outs in operation

• 2 MEBT scrapers ` in operation

• 1 MEBT chopper in operation

• 5 Ring Electron Detector read-outs commissioning

• Momentum Dump Diagnostics

– 2 scraper read out commissioning

– 4 Beam Loss Monitors (BLMs) installing

– 1 Wire Scanner (WS) installing

– 1 NanoCurrent Detector (NCD) manufacturing

– 1 Beam Current Transformer (BCM) designing

• Ring Injection Dump Line Upgrade

– 3 BPMs designing


“In the transverse phase plane, the Laser Wire Scanners are remarkable instruments capable of monitoring transverse beam evolution along the linac and during the pulse. It is regrettable that they cannot presently be used to their full potential, mostly because of stability problems. The committee urges the implementation of the improvements proposed by the beam

instrumentation specialists. ”

AAC’09 Recommendation on Laser Wire


Laser wire profile scanner

Faraday Cup

Laser

H-

H0

electron

Bending

Magnet

Y-scan

y z


SCL

1 2 3 4 5 321712 13 14 15

250 m 227 m 25 m160 m

LR Laser room

Laser wire station

Cryomodule number

Camera

Mirror

Power meter32

LR

Ring

Layout of the SCL Laser Wire System

CCLDTL

Target

MEBT

• 4 LW from 200 MeV

• 4 LW from 450 MeV

• 1 LW at 1 GeV


Periscope box upper mirror – hidden corner –

identified as a major source of the laser

beam vibration

Pipe A: ~ 8 m

Pip

e B

: ~

2.5

m

Mirror

Laser beam

Concrete


Installed New Mirror Holder


Feedback Off

-20

0

20

40

60

80

0 100 200 300 400 500 600

Time (sec)

Po

siti

on

(m

m)

0

2

4

6

8

10

Po

wer

(W

)

CAM05_PosY Power Meter 01Feedback Off

-20

0

20

40

60

80

0 300 600 900 1200 1500 1800

Time (sec)

Po

siti

on

(m

m)

0

2

4

6

8

10

Po

we

r (W

)

CAM05_PosY Power Meter01

May 29, 2009 Aug. 12, 2009Beam position Y on Cam5

Laser power measured at LW1

Improvement of laser beam stability


Profile-Station_02-HORIZ-2009-10-01_16-36-54

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25 30 35

Position (mm)

Am

pli

tud

e (V

)

Amp Fit Profile-Station_02-VERT-2009-10-01_16-54-28

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

5 10 15 20 25 30 35 40

Position (mm)

Am

pli

tud

e (V

)

Amp Fit

Profile-Station_01-HORIZ-2009-10-01_17-01-31

0

0.2

0.4

0.6

0.8

1

5 10 15 20 25 30 35 40

Position (mm)

Am

pli

tud

e (V

) Amp Fit Profile-Station_01-VERT-2009-10-01_17-12-53

0

0.2

0.4

0.6

0.8

1

15 20 25 30 35 40 45

Position (mm)

Am

pli

tud

e (V

)

Amp Fit

LW 1

LW 2


Improvement of profile measurement

(noise reduced by 30-60%)

LW Station # 1 2 3 4 12 13 14 15 32

Previous

run

13.5% (H)

11.0% (V)

12.1

11.8

8.8

10.7

10.0

7.4

7.6

6.8

7.6

6.8

7.3

8.1

6.7

6.8

4.5

4.8

This run

4.2% (H)

5.0% (V)

5.0

4.7

5.4

6.2

6.6

6.6

3.7

3.3

4.3

4.5

3.5

3.5

4.1

4.4

4.1

4.0

STD Measurement Noise

Y. Liu


Verification of LW data self-consistency

LW 12V Cam17 Pos: (81,88)

Focus Lens

Pos (mm) s_V (mm) Amp_V (V) C_V (mm) E_V (%)

0 3.12 0.94 22.98 5.47

2 3.14 0.89 22.88 3.93

4 3.14 0.79 22.96 4

6 3.18 0.66 23.01 3.98

8 3.17 0.59 23.06 3.49

10 3.14 0.65 22.97 3.28

LW12 Oct.15, 2009

Ion beam power: 800 KW

Laser pulse

energy (mJ) s_H (mm) s_V (mm) Amp_H (V) Amp_V (V) E_H (%) E_V (%) C_H (mm) C_V (mm)

75 2.45 3.07 0.35 0.37 4.9 4.2 19.8 22.95

150 2.46 3.11 0.67 0.64 4.1 4.8 19.76 23.13

225 2.37 3.16 0.9 0.96 4.4 4.1 19.78 23.16

300 2.42 3.13 1.06 1.22 4.3 3.9 19.79 23.02

Beam Center vs. Horizontal Beam Shift

18

20

22

24

26

28

30

32

-6 -4 -2 0 2 4 6

Horizontal Beam Shift (mm)

Mea

sure

d B

eam

Cen

ter

(mm

)

X0 (mm) Y0 (mm)


Summary of laser wire system status

• Laser Wire system has been improved and verified to give reliable profile measurement.

• Measurement noise has been reduced by 30-60%.

• System is available to AP with help from BIG experts.

• Trained Operation’s Accelerator Specialist in operating the Laser Wire.

• Laser Wire is used often during neutron production

• First Laser Wire journal paper - Laser wire beam profile monitor in the SNS Superconducting linac – published in NIMA.


On-going efforts

• Laser wire bump compensation magnet (design has been finished, sent out for quotation request).

• Feedback bandwidth improvement (from 1 Hz to 15-30 Hz).

• Laser energy pulse-to-pulse measurement at laser wire station.

• Simultaneous profile measurement at multiple laser wire stations (currently two-station measurement was made available on hardware).


Laser wire station with the compensation magnet

Magnet for collecting

electrons

Compensating magnet


Compensating magnet is designed to be connected

to power supply in series with the main magnet

Sent for manufacturing

Plan to install during summer 2010 outage

A. Menshov


• “…The only possibility to measure transverse beam halo down to the 10-5 level is with the HEBT beam scraper. Transforming this scraper into a fully functional halo monitor is essential to help understand the process of halo formation and minimization….”

– We equipped the HEBT scraper with large dynamic range charge sensitive electronics. AP started to use it ( J. Galambos’s talk)

– We are looking into possibility of increasing measurement dynamic range of all SNS wire scanners

AAC09 Recommendation on large

dynamic range profile measurements


Limitations in Large Dynamic Range

Measurements with SNS Wire Scanners

Signal in the beam tail is dominated by

the cross-talk between the wires

#1


Cross-talk between the wires

X

Large separation

between the wires

helps to reduce the

cross talk


Performance of the CCL WS with diagonal

wire removed

Modified all DTL and HEBT wire scanners during January outage


• “… In the accumulator ring, the committee is favorably impressed by the preliminary results obtained with the electron scanner and encourages its further development ….”

– Installed magnetic shielding, which improved stability of measurements greatly

– Electron beam energy of 60kV is significant limitation. Initiated collaboration with Budker Institute of Nuclear Physics for increasing operating energy to 100kV

AAC09 Recommendation on ring profile

measurements using electron beam


Effect of Magnetic Shields on electron beam trace

After shielding: Dipole current at 0 amps (top) and

4000 amps (bottom)

Before shielding: Dipole current at 0 amps (top)

and 4000 amps (bottom)


Profile measurement repeatability

Twenty profiles taken without changing settings:

– Nice horizontal repeatability

– Still not so great vertical repeatability

W. Blokland


Electron beam energy is too low

Curvature becomes too strong


• Status of Large Bandwidth Feedback System for the SNS Ring:

– Tested analog system with beam

– Have demonstrated e-p instability suppression

– Need more study time for better understanding of the system

– Digital controller is on the way

28 Managed by UT-Battellefor the U.S. Department of Energy Presentation_nameTuesday, February 03, 2015

Damper system components in

the ring service building

Amplifier set

Vertical Comb

Filter

Fiber

Optic

Delays

Power

Combiners

Horizontal LLRF

Vertical LLRF

Horizontal

Comb Filter

Broad band 800W amplifier.

1-300 MHz BW

C. Deibele


Vertical Damper Test Results R. Hardin

OffOn


New pick up and kicker hardware

Blue = Measured

Red = Simulated


High power mode-locked laser for laser stripping is

installed in the new laser room


Laser beam parameters are sufficient for

the next laser stripping experiment

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

0 2 4 6 8 10

Time (us)

Outp

ut

(volt)

UV power: 2.5 W/macro-pulse

120 uJ/micro-pulse (2.2 MW peak power @ 55 ps)

402.5 MHz

Measured full pulse width: 69 ps (green light).

Estimated UV light pulse width: ~ 55 ps.

Y. Liu



Summary

• Existing Beam Instrumentation is capable to support machine tuning and production runs

• Downtime associated with beam diagnostics is low. Goal is to not exceed 10 hours next year

• Laser wire is brought to routine operation status. Have several improvements in works

• Removing the diagonal wire allowed to demonstrate 10^4 dynamic range on CCL wire scanner. Expanding modification to DTL and HEBT wires.

• Reduction of AP beam time requires Improvement of BI user interface and speed up of measurement

– bringing BSM and MEBT emittance devices to “user friendly” status is main goal for this year

beam instrumentation performance and plans · 2 managed by ut-battelle for the u.s. department of...

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