Beam Commissioning- In Perspective of the High-level Applications -

R. MiyamotoAD/BPODG/BPS

Beam Physics High Level Applications ReviewMarch 7th, 2017

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Outline

● Beam commissioning overview● Applications needed during beam commissioning● Conclusions

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Beam Commissioning Overview

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Timeline of beam commissioning(and selected ESS-wide milestones)

2018-02-05 ~ 2018-03-11 Beam commissioning up to LEBT2018-09-17 ~ 2018-10-14 Beam commissioning up to MEBT2019-01-28 ~ 2019-03-03 Beam commissioning up to DTL42019-06-10 ~ 2019-06-23 Beam commissioning up to tuning dump (570 MeV)2020-04-xx Target ready (no beam yet??)2021-03-xx First neutron instrument ready (first beam to target??)2023-08-xx User program starts2025-xx-xx 5 MW beam power??

● This schedule is as of today!● Ion source and LEBT will be commissioned in Italy by the in-kind partner so what

we do is re-commissioning.● Linac Group is responsible for the source and the transition of the responsibility

occurs during the LEBT beam commissioning.● The beam power will be limited to 12 kW until the target is ready.

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Normal conducting linac commisioning

● Beam commissioning of the normal conducting linac is done in parallel to installations of the rest of the linac components.

● A temporary beam stop is used at each step.● Beam parameters will be limited during these periods to limit the

radiation dose.

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Beam modes

Section/type Current [mA]

Pulse length [us]

Rep rate [Hz]

Main usages

IS, LEBT 6 - 90.0 ≤ 6000 ≤ 1RFQ, MEBT 6 - 62.5 ≤ 50 ≤ 1DTL1 6 - 62.5 ≤ 50 ≤ 1DTL2-4 6 - 62.5 ≤ 5 ≤ 1Probe 6 ≤ 5 ≤ 1 - Initial check

- Beam threadingFast tuning 6 - 62.5 ≤ 5 ≤ 14 - RF setting

Slow tuning 6 - 62.5 ≤ 50 ≤ 1 - Invasive measurement- LLRF setting

Long pulse verification

6 - 62.5 ≤ 2860 ≤ 1/30 - Beam loss check- Lorentz detuning check

NC

L comm

ission ingStandard

● Beam physics is NOT responsible for the highest level application to select an operation mode the linac such as the beam mode, destination, and etc.

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Temporary and permanent beam stops

Location Mode LimitsLEBT (exit) Temporary 1 HzMEBT (exit) Temporary (50 us, 1 Hz)DTL (tank 4 exit) Temporary (5 us, 1 Hz)LEBT (between the solenoids) Permanent N/AMEBT (before the final quadruplet) Permanent (5 us, 14 Hz), (50 us, 1 Hz)DTL (tank 2 exit) Permanent (5 us, 14 Hz), (50 us, 1 Hz)DTL (tank 4 exit) Permanent (5 us, 14 Hz), (50 us, 1 Hz)Spokes (doublet #1) Permanent (5 us, 14 Hz), (50 us, 1 Hz)Medium-β (doublet #6) Permanent (5 us, 14 Hz), (50 us, 1 Hz)Dump line Permanent (5 us, 14 Hz), (50 us, 1 Hz), 12 kW*Target Permanent N/A

Dump line

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Applications needed during beam commissioning

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Tuning types

● General– Polarity– Beam based alignment

● LEBT– Iris vs current– Chopper timing/voltage– Gas pressure vs space charge compensation

● RFQ– Power vs energy/transmission– LEBT solenoids/steerers vs transmission

● MEBT– Chopper timing/voltage– Collimator positions

● A2T (including dogleg)– Achromatic condition– Raster system

● Trajectory correction● Phase scan● Matching with 3(+) profiles● Twiss/emittance with quad/buncher scan● Difference trajectory + linear model

– Quad transfer function– Transfer matrix– ...

● Input beam reconstruction and matching based on the emittance measurement.

● ...

Simple scan-and-check Standard

Off-line

● Most of tunings are either a simple scan-and-check or standard type of tuning.

● Viewers are important but not our scope.

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LEBT layout

BCMDopplerNPMEMU

FC

NPM

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ISrc+LEBT tuning

Knob Beam parameter DiagnosticsMicrowave, B field, Gas Current

Proton fraction(HV, FC, BCM)Doppler

HV Energy HV power supply (Doppler)Microwave Pulse length HV, FCChopper Pulse length BCMSteerers Trajectory

Transmission (RFQ)NPM, EMUBCM (MEBT)

Solenoids Twiss (x,y)Transmission (RFQ)

EMUBCM (MEBT)

Iris Current FC, BCMGas Emittance, Twiss (x,y)

Transmission (RFQ)EMU, NPMBCM (MEBT)

Courtesy of Ø. Midttun

● Tuning of the LEBT is mostly scanning a knob and checking the corresponding diagnostics device.

● We need applications for 1D and 2D scans.

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MEBT layout

BCMFCM

Col ColCol Dump

WS WSNPM

WSSlit

BSMGridNPM

BCMBCM

Chopper

BPM*

MatchingChopping

FC

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RFQ+MEBT tuning

Knob Beam parameter DiagnosticsRFQ power Energy

TransmissionBPMBCM

Steerers Trajectory BPMBuncher 1 phase Energy* BSMBuncher 1 amp Bunch length BPMBuncher 2-3 phase Energy* BSMBuncher 2-3 amp Twiss (z) BPMQuad 1-4 Beam size (x,y) in chopping WS (EMU)Quad 5-11 Twiss (x,y)

Beam size (x,y) in matchingEMU (WS)WS (EMU)

Chopper Pulse edge BPM*, FCMCollimator Halo (x,y)

Pulse edgeBuilt-in sensor (WS, EMU)BPM*, FCM

● MEBT beam commissioning requires standard applications, such as the trajectory correction, phase scan, and matching, thus defining the deadlines for most of our high-level applications.

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DTL layout and tuning

Knob Beam parameter Diagnostics

Steerers Trajectory BPMTank 1 phase Energy

TransmissionBPMBCT

Tank 1 amp Energy BPMTank 2-5 phase, amp Energy BPM

● Our DTL uses permanent quads and the only tunings we can do are the phase scan and trajectory correction.

● Phase scans of DTL tanks could be more complicated than those for other cavities.

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Superconducting sections and HEBT

● Superconducting sections and HEBT require standard tunings of– trajectory correction– phase scan– Twiss and emittance measurement with a quad scan and 3 profile

measurements– Twiss and emittance matching

● The applications for these types of tunings should be already developed and used for the preceding sections.

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Spoke section layout and tuning

● Major part of the tuning of the spoke section is the phase scans for 26 cavities.● 1 BPM per period. The location alternates near Qh and Qv. (The same in the rest

of the linac, except in A2T.)● Matching at the interfaces.

– 3 WSs and 1 BSM in the initial part allow the transverse and longitudinal matching.– To DTL: the design uses 4 cavities and 4 quads.– To Medium-β: the design uses 2 cavities and 2 quads.

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Medium-β linac layout and tuning

● Major part of the tuning of the medium-β is the phase scans for 36 cavities.● Matching at the interfaces.

– Due to the frequency jump, the spoke and medium-β interface is one of the most vulnerable points in the linac.

– 3 WSs and 1 BSM in the initial part allow the transverse and longitudinal matching.– To spoke: the design uses 8 cavities and 2 quads.– To high-β: the design uses 4 cavities and 2 quads.

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High-β linac layout and tuning

● Major part of the tuning of the medium-β is the phase scans for 36 cavities.● Matching at the interfaces.

– Because of no change in lattice periodicity, there is only 1 WS as a placeholder.– To medium-β: the design uses 4 cavities and 2 quads.

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HEBT and dogleg layout and tuningH

EBT

Dog

leg

● Matching at the interfaces.– 3 WSs in the later part of the HEBT allows the emittance measurement and matching.– To high-β: the design uses 8 quads.

● Dispersion is measured with BPMs in A2T.

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A2T tuning

ImageGridAperture

BPMAperture

NPM WS?

Knob Beam parameter DiagnosticsSteerers Trajectory BPM, image, gridQuad 5-6 AP to CO phase advance BPM at CO (w/ raster steerers)Quad 1-4 Beam sizes on the target

Beam sizes (waists?) in NSWImage, grid (NPM, WS?)NPM, WS? (image, grid)

Raster Footprint on the target Image, grid (w/ raster steerers)

Steerers for emulating raster motion

● A2T has a special optics and raster system to expand the beam for target.

● The tuning process still consists of the scan-and-check and transverse optics measurement followed by the matching.

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Conclusions

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Conclusions

● Beam commissioning– Beam commissioning will start early next year from the re-commissioning

of the ion source and LEBT.– In mid-2019, we will be ready to send the 570 MeV but low power (12 kW)

beam to the tuning dump.– The power ramp-up will be after the target becomes ready in 2020. Thus,

the early focus is on the basic tunings such as the RF phase and amplitude (and not so much on the losses, I hope).

● Applications for beam commissioning– Most of the tunings are either a simple scan-and-check or standard types.

(Needless to say that we still need careful simulation studies and preparations of applications.)

– Most types of the applications will be necessary for the MEBT commissioning in late 2018 (or early 2019?).

– Transport lines (LEBT, MEBT, and A2T) are unique and have special functions. So, we have to develop several applications specific for these sections.

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Backup slides

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A2T layout

Locations of steerers (4) and BPMs (6) being updated

Courtesy ofH. Thomsen