[PPT] - PIP-II Injector Test Warm Front End: Commissioning Update Lionel PowerPoint Presentation

SLIDE 1

In partnership with: India/DAE Italy/INFN UK/STFC France/CEA/Irfu, CNRS/IN2P3

Lionel Prost 9th International Particle Accelerator Conference April 29 – May 4, 2018 Vancouver, BC, Canada

PIP-II Injector Test Warm Front End: Commissioning Update

FERMILAB-SLIDES-18-100-AD This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE- AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.

SLIDE 2

Acknowledgement

Results summarized within would not have been possible

without the help and dedication of many (and I apologize in advance for missing some), in no particular order:

D. Sun, A. Chen, P. Jones, D. Franck, D. Lambert, R. Kellett, C.

Baffes, J. Batko, J. Czajkowski, T. Hamerla, T. Zuchnik, C. Briegel,

J. Firebaugh, S. Conlon, G. Brown, R. Hagler, A. Saewert, G.

Saewert, D. Frolov, V. Lebedev, R. Pasquinelli, A. Shemyakin, J. Steimel, B. Hanna, R. Andrews, J.-P. Carneiro, K. Carlson, B. Chase, D. Peterson, J. Edelen, J. Dye, W. Mueller, J. Einstein- Curtis, D. Sharma, S. Khole, V. Scarpine, B. Fellenz, N. Eddy, A. Warner, D. Nicklaus, M. Kucera, D. Arveson, A. Saini, E. Cullerton,

M. Hassan, K. Kendziora, P. Derwent, M. Coburn, M. Ibrahim,

V.L.S. Sista, C. Richard

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Designates co-authors

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SLIDE 3

Outline

Proton Improvement Plan II (PIP-II) & PIP-II Injector Test

(PIP2IT)

– Introduction, scope & goals for the Warm Front End (WFE)

PIP2IT WFE commissioning status

– Focus on Medium Energy Beam Transfer (MEBT) line

Plans for high-power operation

– 10+ kW

Conclusion

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SLIDE 4

Proton Improvement Plan-II (PIP-II)

Upgrades to Fermilab’s accelerator complex

– Central part: 800 MeV, 2 mA (average over ~ms) CW-compatible H- Superconducting Linac and transfer line to Booster

Present ‘warm’ Linac: 400 MeV, 30 mA, 40 ms×15 Hz

– MW-class accelerator with multi-user operation capability

Platform for future upgrades

– Higher Main Injector power, multiple experiments simultaneously

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L. Prost et al. | PIP-II WFE Commissioning Update (THYGBF2)

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Layout of PIP-II and its possible future upgrades

S. Nagaitsev’s

talk (MOYGB3)

PIP2 linac and transfer line Booster Linac Muon rings

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I I I I I I I I I I I

SLIDE 5

PIP-II Injector Test (PIP2IT)

A test accelerator representing the PIP-II front end

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PIP-II Linac scheme

~160 m

30 keV RFQ MEBT HWR SSR1 HEBT 2.1 MeV 10 MeV 25 MeV LEBT Warm front end

LEBT = Low Energy Beam Transport; RFQ= Radio Frequency Quadrupole; MEBT= Medium Energy Beam Transport; HWR = Half-Wave Resonator; SSR1=Single Spoke Resonator; HEBT = High Energy Beam Transport

PIP2IT scheme

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162.5 MHz 0.03 -10.3 MeV 325 MHz 10.3-185 MeV 650 MHz 185-800 MeV

SLIDE 6

Warm Front End scope

The Warm Front End (WFE) prepares a H- beam optimized

for injection into the Booster and provides capabilities for future CW operation

It is composed of:

– Two Ion Sources (IS) and a Low Energy Beam Transport (LEBT)

DC/long pulse operation

– RFQ

CW operation (RF)
30 keV

2.1 MeV

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– Medium Energy Beam Transport (MEBT)

Nominal output current: 2 mA

averaged over ~ms (from ms to CW

peration)
Bunch-by-bunch chopping

capability

Ion sources LEBT RFQ MEBT

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SLIDE 7

PIP2IT WFE main goals

Address all critical issues:

– LEBT with low emittance growth compatible with chopping

Vacuum management in the LEBT/RFQ region

– Reliable CW RFQ, including couplers – Bunch-by-bunch selection in MEBT

Bunch extinction, effective

emittance growth

– Compatibility of high-power deposition in MEBT absorber with SRF downstream

Absorber reliability &

lifetime

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Warm front end of PIP2IT with HWR installed

Reported previously

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SLIDE 8

LEBT and RFQ performance highlights

LEBT delivers up to 10 mA, 10ms-dc, 20 Hz

– en,rms = 0.13 mm mrad (for 5 mA)

RFQ operated pulsed (up to 5 ms) or CW, 162.5 MHz, 60 kV

– Time of Flight measurements → 2.11±0.006 MeV – 98±2% transmission efficiency at 5 mA (pulsed beam)

Up to 10 mA with low losses

– en,rms < 0.2 mm mrad (for < 5 mA, nominal)

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L. Prost et al. | PIP-II WFE Commissioning Update (THYGBF2)

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MEBT configuration for characterization of the RFQ

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Emittan

SLIDE 9

PIP2IT beam line configuration

Full length MEBT has been installed at the CryoModule Test

Facility (CMTF) followed by a high-power dump

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– Includes two different prototype kickers (50-Ohm & 200-Ohm), all scraper paddles, prototype absorber, Differential Pumping Insert (DPI) and various diagnostics

Absorber prototype 50-Ohm kicker prototype 200-Ohm kicker prototype DPI F-scraper Fast acting valve ACCT Emittance scanner Fast Faraday Cup RWCM

Dump

Ion Source & RFQ

DPI

200-Ohm kicker

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SLIDE 10

Beam transport

Demonstrated 96% availability (over 24 hours) for beam with

nominal MEBT parameters

– 5 mA×0.55 ms×2.1 MeV×20 Hz = 115 W with appropriate bunch pattern for Booster injection

Up to 10 mA to the dump with negligible uncontrolled losses

– Dedicated distributed scraping system removes ~2% (halo)

Measured beam emittances near the end of the MEBT

– 0.22/0.34 mm mrad (rms, n) Transverse/Longitudinal

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Angle, mrad Position, mm

erms,n = 0.22 mm mrad

Vertical phase- space with Allison scanner (5 mA, 10 ms pulse) Bunch length vs. bunching cavity #2 voltage (5 mA, 10 ms pulse) and ‘fit’ with Tracewin

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SLIDE 11

Chopping system concept

2 identical kickers in sync and a beam absorber

– Two broadband travelling-wave kickers separate bunches by 6s – Absorber is rated for 21 kW (i.e. full max. beam power)

Beam comes at 29 mrad to decrease power density to <17 W/mm2

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3σ envelopes of the transmitted (a) and chopped-out (b) bunches simulated with TraceWin.

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Position (m)

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SLIDE 12

Kickers development

Two versions developed in parallel  1 of each prototype

installed at PIP2IT

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“50-Ohm”

➢ 24 electrodes per plate connected in vacuum by 50 Ohm cables ➢ Driver: commercially available linear amplifier ▪ Concept tested with similar lower-power amplified

D. Sun
A. Chen

“200-Ohm”

➢ Helix as a travelling-wave structure ➢ Driver developed at Fermilab ▪ Broadband, DC-coupled switches in push-pull configuration

A. Chen
G. Saewert
G. Saewert’s poster

(WEPML021)

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Demonstrated arbitrary bunch structure

– Kicked bunches intercepted with a scraper → passing bunches recorded with Resistive Wall Current Monitor (RWCM)

Kickers characterization

Both kickers (50-Ohm and 200-Ohm) meet specs

– For DV = 500 V (nominal), angle of deflection at the end of either kicker is > 7 mrad (specs)

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2.4 ms

Kick

Top scraper partially inserted

RWCM

200-Ohm kicker DPI

T. Hamerla
F. Frolov
G. Saewert
J. Simmons
D. Sun
G. Saewert
A. Chen
B. Chase
V. Lebedev

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SLIDE 14

Kickers characterization(cont’)

Kickers do not significantly deteriorate

the transverse emittance of the beam

Kickers were successfully operated

together in sync

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5 mA beam collimated to 1.5 mA and deflected by the 200-Ohm kicker

3s vertical envelope simulated with Tracewin showing both the passing and the deflected bunches in the configuration with both kickers used in sync.

50-Ohm Kicker 200-Ohm Kicker DPI F-scraper

Angle, mrad Position, mm

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Fast acting valve Emittance scanner

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ACCT Fast Faraday Cup

SLIDE 15

PIP2IT vs. PIP-II WFE beam parameters

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At PIP2IT, the bunch pattern for bucket-to-bucket injection into the Booster was demonstrated using only 1 kicker (2 are required to achieve nominal deflection)

* Arbitrary patterns are currently limited to 0.6 ms bursts with average switching frequency of up to 45 MHz during

the burst and 20 Hz bursts repetition rate

PIP-II Beyond PIP-II (cw) PIP2IT (concurrently) PIP2IT (max) Beam energy, MeV 2.1 2.1 2.1 2.1 Bunch frequency, MHz 162.5 162.5 162.5 162.5 Peak current (RFQ exit), mA 5 5 5 10 Macro-pulse length, ms 0.55

0.55

4.8 Macro-pulse rep. rate, Hz 20

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60 Bunch pattern Booster inj. Arb. Booster inj. Arb.* Output current (averaged over ~ms), mA 2 2 2 10 Average power, kW 0.1 10 0.1 5

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SLIDE 16

Path to high-power operation

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RFQ consolidation

– RFQ couplers were replaced with a new design where the ceramic window is sealed with Viton O-rings (instead of brazing)

Identified solutions for the

high-power absorber

Machine Protection System (MPS)

– Protection against unexpected and sudden beam loss is critical for going to higher beam power/duty factor

Compare current measurements along the beam line

– Complications:

Beam is slightly scraped off on purpose
Beam current along the beam line varies by design
S. Kazakov
O. Pronitchev

Copper nut Rotatable flange Hole for ceramic cooling air

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Rotatable flange

SLIDE 17

Absorber: Main challenges

Three major challenges

– Dissipate high-power beam  Shallow angle of incidence – Significant amount of beam is reflected (~20%)

Limit propagation downstream
Manage power going to the walls of the vacuum box

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L. Prost et al. | PIP-II WFE Commissioning Update (THYGBF2)

17 Simulation of secondary particles incident on the downstream wall

f the absorber box for a flat

absorber surface

Downstream wall of vacuum box (beam going into the page)

Absorber

>800 W escape

Vacuum chamber aperture

C. Baffes
J. Batko
S. Oplt

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SLIDE 18

Absorber fabrication status

Baffling techniques have been used to limit transmission of

secondary particles downstream

Downstream wall was made with a grid pattern to localize

thermal stress and includes multiple layers

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Downstream wall of vacuum box (beam going into the page)

Design complete

– Procurement has started

Absorber assembly cutout model

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SLIDE 19

Summary

PIP-II Injector Test WFE works as an integrated system and

demonstrated key technical aspects of the PIP-II WFE design, in particular for the MEBT:

– Arbitrary bunch selection pattern – Two kickers working in sync – Beam to the dump at nominal parameters (5 mA, 0.55 ms, 20 Hz) with low losses and all aperture restrictions (kickers, DPI) – Most beam parameters within specs

Most components have been tested with ~1 kW beam

– Moving forward with demonstration of ~10 kW+ operation

Machine Protection System is key

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SLIDE 20

Plans

Prepare for a ~2-year hiatus in the operation of PIP2IT with

beam

– For cryomodules installation and testing (RF)

Then, proceed with final round of tests of the MEBT

– Production kickers & absorber

Extinction measurements

– Emphasis on vacuum management and protection of SRF from failures upstream

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