Melbourne X-band Status and Plans CLIC meeting 5/10/2021 - Dr. Suzie Sheehy Senior Lecturer, University of Melbourne Baker/ANSTO Fellow in Medical ...

Melbourne X-band
Status and Plans
CLIC meeting
5/10/2021
Dr. Suzie Sheehy
Senior Lecturer, University of Melbourne
Baker/ANSTO Fellow in Medical Accelerator Physics
suzie.sheehy@unimelb.edu.au
@suziesheehy 1

 Image: M. Volpi

Accelerator Physics @ Melbourne University
 X-band (Compact) Accelerators:
 • Dr. Matteo Volpi
 • Prof. Geoff Taylor
 • A/Prof. Roger Rassool
 • Scott Williams (PhD)
 • Paarangat Pushkarna (MSc)
 • James Dawkins (MSc)
 Hadron Therapy & Medical Accelerators:
 • Dr. Jacinta Yap
 • Greg Peiris (PhD)
 • Frank Zhang (PhD)
 An outstanding accelerator R&D programme to underpin training of
 • Adam Steinberg (PhD – Manchester)
 future accelerator experts was highlighted as a key recommendation
 • Hannah Norman (PhD – Manchester)
 • Elodie Higgins (MSc – completed)
 in the 2015 Australian Academy of Science
 Honoraryreport
 Members:
 • Dr. Rohan Dowd (ANSTO)
Some of the group visiting the Australian Synchrotron • Dr. Rebecca Auchettl (ANSTO)
 • Dr. Eugene Tan (ANSTO)
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 • Choiphy Zhao

The “X-BOX3” formerly at CERN…

Total power < 50 MW
2 x Toshiba 6MW 5us klystron
2 x Scandinova Modulators
Nominal Rep Rate 400Hz

Developed for ‘CLIC’ Compact
Linear Collider Project

On it’s way in late 2020…

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M.VOLPI

Arrival in Melbourne!

 5

Equipment Arrival
COSMOS magazine CERN News UniMelb News

 6

Melbourne is hosting the first high-frequency high-
gradient accelerator lab in the Southern Hemisphere

 7

X-LAB: X-band Laboratory for Accelerators and Beams
 PROGRAM 2021 - 2026
 Note: synchronized with ANSTO/Australian Synchrotron plans

Phase 1: X-band Research & Establishment
 Conditioning of Reconfigure to
ARC Linkage Proposal Design for Rf pulses with
 TD24 & accelerating
R3, 2020 applications beam
 algorithm mode
Baker Foundation (TBC)

Phase 2: 40 MeV tunable, pulsed electrons & applications
ARC LIEF proposal
R1 2021 (TBC) Design & Procurement Beamline • Progress application-based research: space
w. ANSTO, Wollongong & simulation of beamline commissioning dosimetry, biophysics, radiotherapy, etc…
Sydney

 2022 2023 2024 2025/6

 Heavy work, First X-
 water & Electron Compton light source
 band rf experiments?
 electricity gun added
 pulses
 completed

Phase 0:
 1: Accelerator
 Refurb & Installation
 Test Stand

 E D Bunker used to

 OV
 house a 35 MeV

 P R
 betatron

 N G AP
 N D I
 FU
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M.VOLPI

Current status of bunker/control room

 10

M.VOLPI

FLUKA simulation

M.VOLPI

 Structure Shielding – at CERN
Lead bricks around the downstream
Faraday Cup (default shielding)
5-10 cm tick lead box

M.VOLPI

 Dose Equivalent

Setup Summary
• 20 MeV
• 100ns flat top
• 0.5 mA dark current
• 200 Hz repetition rate
• 2000 working hours per year, (40h/week x 50
 weeks)
• Extra shields:
 – Lead bricks around downstream faraday cup
 – Wall bricks around the structures

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M.VOLPI
 P. PUSHKARNA
 A Phase 1 Research Avenue…
- RF breakdown is destructive to beam & accelerator
- Need to be able to:
 - predict breakdown
 - Optimise “conditioning” (variation of input pulses over time)
 - With up to 400Hz pulse rate, potential for high data rate

 Can we build a machine learning algorithm
 to optimize conditioning process

 TD24 structure so far reached 40.45 MW (97.9 MV/m)

 (ns)

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 CLIC structures high power tested so far.

Phase 2: Electron beamline project
 Co-develop accelerators for applications

Potential electron and X-ray users: Accelerator developments:
• Biophysics studies • Compact Light Source development
• Electronics and dosimetry (space applications) • VHEE accelerating structures
• Diagnostics development • Structures for in-field industrial scanning applications
• Novel radiotherapy technology
+ much more!

S. WILLIAMS
 M. VOLPI
 Beamline Simulations
After capture and acceleration, simulations show the system will be able to provide:
• electron beam energies of 3-40 MeV,
• 125 keV energy spread,
• emittance of 1 .mm.mrad
• pulse length of 150 μm.
• Pulse rate 3 Hz based on the S-band gun but could be upgraded in future.
• Charge per bunch is 0.1 nC and dose rate is 12 mJ/sec.
All parameters are tunable, these represent the optimum set.

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Building the ‘ecosystem’ as well as the lab…

Other applications/partnerships:

 • Successfully established links with ANFF
 (Adelaide) to produce the FIRST X-band high
 power RF components ever made in
 Australia
 • …now preparing to invest in $millions for a
 “nanomill”

Thankyou

Dr. Suzie Sheehy
@suziesheehy

 Pictured: X-LAB visit by Moira O’Bryan, Dean of Science, UniMelb (Photo: M. Volpi)

Extra slides

UoM limits

The calculation assume that a person will work 50 weeks a year. Annual dose limit at UoM
1mSv , weekly dose rate cannot exceed 20 uSv/week over 50 weeks.
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Running conditions
 Minimum Maximum Average NOTE

Power n/a 18MeV < 10MeV Max=20MeV if PC is detuned +1.5MHz

Dark Current 0.25mA/pulse 1.25mA/pulse 0.5mA The DC decrease during the conditioning

Flat Top 50ns 200ns 100ns The DC decrease at high pulse because
 the conditioning started stated with small
 pulse
Repetition 50Hz 200Hz 100Hz At 200Hz, hard keep tuned the PC
Rate/structure

Working time n/a 40h/week We can’t stay longer in the bunker due to
 the klystron noise
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Dose Equivalent
Setup Summary
• 20 MeV
• 100ns flat top
• 0.5 mA dark current
• 200 Hz repetition rate
• 2000 working hours per year, (40h/week x 50
 weeks)
• Extra shields:
 – Lead bricks around downstream faraday cup
 – Wall bricks around the structures

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Dose Rate
Setup Summary
• 20 MeV
• 100ns flat top
• 0.5 mA dark current
• 200 Hz repetition rate
• 2000 working hours per year, (40h/week x 50
 weeks)
• Extra shields:
 – Lead bricks around downstream faraday cup
 – Wall bricks around the structures

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Dose-Equivalent (not Dose)
• For some quantities, there is the possibility to get built-in conversions, without the
 need for user routines, rather through dedicated generalized particles. The most
 commonly used is dose equivalent (ambient dose equivalent or effective dose):
DOSE-EQ Dose Equivalent [pSv]
DOSE total absorbed dose in GeV/g

• DOSE-EQ is calculated by folding particle fluences with conversion coefficient sets, selected by
 the user among a list (see manual) through AUXSCORE. The default set (not requiring the
 AUXSCORE association) is “AMB74”.
• I am using EWT74 (Valencia Setup)
Renormalization factor
• Dark current ~0.5mA/pulse
• 1A= 6.24x10^18 e/sec => 6.24x10^18 * 0.4x10^-4 = 2.5 x10^14 25

Normalisation
We need to times the dark current by the duty factor which is 10^-7 roughly (100ns flat top).
• They have 0.5mA for say 100ns, which is 50pC, at 200Hz this gives an average current of 10nA
• Current per pulse ~0.5mA Repetition rate is 200Hz (400Hz/2 two test stands)
• Then 2.5 x10^14 x 200= 5x10^16x10^-7 = 5x10^9
Summary
• 5e9 : beam intensity is 5e16 electrons/s
• 1e-6 conversion pSv to uSv
• 3600 conversion from 1/s to 1/h
• 2000 working hours per year 40h/week x 50 weeks
Electron energy :20 MeV
DOSE
• DOSE with the same normalization of DOSE-EQ * 1.6e-7
• Does unit transfers from GeV/g to Gy by a factor 1.6e-7.
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