LINAC2022 - List of Authors (Welsch, C.P.)

Paper	Title	Page
MOPORI03	Development of Quantum Gas Jet Beam Profile Monitor for Sub-mm Beams	223
	N. Kumar, O. Stringer, C.P. Welsch, J. Wolfenden, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom N. Kumar, C.P. Welsch, J. Wolfenden, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom I. Maltusch FH Aachen, Jülich, Germany
	Funding: This work is supported by the STFC grants ST/W000687/1 and ST/W002159/1, InnovateUK Germinator 10004615, HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1. The development work of a high-resolution quantum gas jet beam profile monitor for highly energetic sub-mm particle beams is in progress at the Cockcroft Institute (CI), UK. This device is designed on the principle of detecting the secondary ions from the ionisation induced in the interaction between the quantum gas jet and charged particle beams. This monitor aims to generate an intense gas jet with a diameter of less than 100 µm, which can ultimately lead to superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. This is done by exploiting the quantum wave feature of the neutral gas atoms to generate an interference pattern with a single maximum acting as an ultra-thin gas jet using an ’atom sieve’ which is similar to the light focusing with a Fresnel zone plate. This device will be minimally interceptive and will work analogously to a mechanical wire scanner. This contribution gives a general overview of the design, working principle of the monitor and experimental results obtained from the electron beam profile measurements carried out at the Cockcroft Institute.
	Poster MOPORI03 [1.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI03
About •	Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI04	A Gas Jet Beam Halo Monitor for LINACs	227
	O. Stringer, N. Kumar, C.P. Welsch, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom N. Kumar, O. Stringer, C.P. Welsch, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom
	The gas jet beam profile monitor is a non-invasive beam monitor that is currently being commissioned at the Cockcroft Institute. It utilises a supersonic gas curtain which traverses the beam perpendicular to its propagation and measures beam-induced ionisation interactions of the gas. A 2D transverse beam profile image is created by orientating the gas jet 45 degrees to obtain both X and Y distributions of the beam. This paper builds upon previously used single-slit skimmers and improves their ability to form the gas jet into a desired distribution for imaging beam halo. A skimmer device removes off-momentum gas particles and forms the jet into a dense thin curtain, suitable for transverse imaging of the beam. The use of a novel double-slit skimmer is shown to provide a mask-like void of gas over the beam core, increasing the relative intensity of the halo interactions for measurement. Such a non-invasive monitor would be beneficial to linacs by providing real time beam characteristic measurements without affecting the beam. More specifically, beam halo behaviour is a key characteristic associated with beam losses within linacs.
	Poster MOPORI04 [1.066 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI04
About •	Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 13 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI05	Application of Virtual Diagnostics in the FEBE Clara User Area	231
	J. Wolfenden, C. Swain, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom D.J. Dunning, J.K. Jones, T.H. Pacey, A.E. Pollard STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom C. Swain, C.P. Welsch, J. Wolfenden Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work is supported by the AWAKE-UK phase II project funded by STFC and the STFC Cockcroft core grant No. ST/G008248/1. Successful user experiments at particle beam facilities are dependent upon the awareness of beam characteristics at the interaction point. Often, properties are measured beforehand for fixed operation modes; users then rely on the long-term stability of the beam. Otherwise, diagnostics must be integrated into a user experiment, costing resources and limiting space in the user area. This contribution proposes the application of machine learning to develop a suite of virtual diagnostic systems. Virtual diagnostics take data at easy to access locations, and infer beam properties at locations where a measurement has not been taken, and often cannot be taken. Here the focus is the user area at the planned Full Energy Beam Exploitation (FEBE) upgrade to the CLARA facility (UK). Presented is a simulation-based proof-of-concept for a variety of virtual diagnostics. Transverse and longitudinal properties are measured upstream of the user area, coupled with the beam optics parameters leading to the user area, and input into a neural network, to predict the same parameters within the user area. Potential instrumentation for FEBE CLARA virtual diagnostics will also be discussed.
	Poster MOPORI05 [0.613 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI05
About •	Received ※ 17 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI06	Improvements on the Modified Nomarski Interferometer for Measurements of Supersonic Gas Jet Density Profiles	235
	C. Swain, Ö. Apsimon, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang Cockcroft Institute, Warrington, Cheshire, United Kingdom Ö. Apsimon, A. Salehilashkajani, C. Swain, C.P. Welsch, J. Wolfenden, H.D. Zhang The University of Liverpool, Liverpool, United Kingdom
	Funding: This work is supported by the AWAKE-UK phase II project funded by STFC, the STFC Cockcroft core grant No. ST/G008248/1 and the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1. For supersonic gas jet based beam profile monitors such as that developed for the High Luminosity Large Hadron Collider (HL-LHC) upgrade, density profile is a key characteristic. Due to this, non-invasive diagnostics to study the jet’s behaviour have been designed. A Nomarski interferometer was constructed to image jets 30 um to 1 mm in diameter and study changes in their density. A microscope lens has been integrated into the original interferometer system to capture phase changes on a much smaller scale than previous experiments have achieved. This contribution presents the optimisation and results gained from this interferometer.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI06
About •	Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO26	Conceptual Design of the PERLE Injector	743
	B. Hounsell, M. Klein, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom B. Hounsell, B.L. Militsyn, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom B. Hounsell, W. Kaabi Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France B.L. Militsyn STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Energy Recovery Linacs such as PERLE require high average current high brightness beams. This sets particular requirements on the kind of injectors that they can use as the injectors must be capable of producing bunches at MHz repetition rates, compressing the bunches to the specified value and transporting those bunches while they are still in the space charge dominated regime into the main ERL all while keeping the emittance low. In particular, PERLE will require a 20 mA beam consisting of 500 pC bunches with a repetition rate of 40 MHz. These bunches will be required to have rms lengths of 3mm, a total beam energy of 7 MeV, appropriate Twiss parameters to match them to the main loop and transverse emittances of < 6 mm mrad. In this paper, a DC gun based injector capable of meeting this specification will be presented with beam dynamics simulation showing the behaviour of the beam from the photocathode to the exit of the first main linac pass. The beam dynamics challenges will be discussed in terms of both the transverse emittance growth and the sources of non-linearity in the longitudinal phase space.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO26
About •	Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOAA02	Welcome to LINAC2022 - Practical Aspects
	C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Welcome to LINAC2022 by the Local Organising Committee Chair with an overview of the practical aspects of this week: the ACC conference center, the excursions on Wednesday, and other information.

	please see instructions how to view/control embeded videos
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Development of Quantum Gas Jet Beam Profile Monitor for Sub-mm Beams

223

N. Kumar, O. Stringer, C.P. Welsch, J. Wolfenden, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, C.P. Welsch, J. Wolfenden, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
I. Maltusch
FH Aachen, Jülich, Germany

Funding: This work is supported by the STFC grants ST/W000687/1 and ST/W002159/1, InnovateUK Germinator 10004615, HL-LHC-UK project funded by STFC and CERN and the STFC Cockcroft core grant No. ST/G008248/1.
The development work of a high-resolution quantum gas jet beam profile monitor for highly energetic sub-mm particle beams is in progress at the Cockcroft Institute (CI), UK. This device is designed on the principle of detecting the secondary ions from the ionisation induced in the interaction between the quantum gas jet and charged particle beams. This monitor aims to generate an intense gas jet with a diameter of less than 100 µm, which can ultimately lead to superior position resolution and high signal intensity resulting from a strongly focused quantum gas jet. This is done by exploiting the quantum wave feature of the neutral gas atoms to generate an interference pattern with a single maximum acting as an ultra-thin gas jet using an ’atom sieve’ which is similar to the light focusing with a Fresnel zone plate. This device will be minimally interceptive and will work analogously to a mechanical wire scanner. This contribution gives a general overview of the design, working principle of the monitor and experimental results obtained from the electron beam profile measurements carried out at the Cockcroft Institute.

Poster MOPORI03 [1.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI03

About •

Received ※ 13 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 30 August 2022 — Issue date ※ 01 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI04

A Gas Jet Beam Halo Monitor for LINACs

227

O. Stringer, N. Kumar, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
N. Kumar, O. Stringer, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom

The gas jet beam profile monitor is a non-invasive beam monitor that is currently being commissioned at the Cockcroft Institute. It utilises a supersonic gas curtain which traverses the beam perpendicular to its propagation and measures beam-induced ionisation interactions of the gas. A 2D transverse beam profile image is created by orientating the gas jet 45 degrees to obtain both X and Y distributions of the beam. This paper builds upon previously used single-slit skimmers and improves their ability to form the gas jet into a desired distribution for imaging beam halo. A skimmer device removes off-momentum gas particles and forms the jet into a dense thin curtain, suitable for transverse imaging of the beam. The use of a novel double-slit skimmer is shown to provide a mask-like void of gas over the beam core, increasing the relative intensity of the halo interactions for measurement. Such a non-invasive monitor would be beneficial to linacs by providing real time beam characteristic measurements without affecting the beam. More specifically, beam halo behaviour is a key characteristic associated with beam losses within linacs.

Poster MOPORI04 [1.066 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI04

About •

Received ※ 24 August 2022 — Revised ※ 26 August 2022 — Accepted ※ 31 August 2022 — Issue date ※ 13 October 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI05

Application of Virtual Diagnostics in the FEBE Clara User Area

231

J. Wolfenden, C. Swain, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
D.J. Dunning, J.K. Jones, T.H. Pacey, A.E. Pollard
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Swain, C.P. Welsch, J. Wolfenden
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work is supported by the AWAKE-UK phase II project funded by STFC and the STFC Cockcroft core grant No. ST/G008248/1.
Successful user experiments at particle beam facilities are dependent upon the awareness of beam characteristics at the interaction point. Often, properties are measured beforehand for fixed operation modes; users then rely on the long-term stability of the beam. Otherwise, diagnostics must be integrated into a user experiment, costing resources and limiting space in the user area. This contribution proposes the application of machine learning to develop a suite of virtual diagnostic systems. Virtual diagnostics take data at easy to access locations, and infer beam properties at locations where a measurement has not been taken, and often cannot be taken. Here the focus is the user area at the planned Full Energy Beam Exploitation (FEBE) upgrade to the CLARA facility (UK). Presented is a simulation-based proof-of-concept for a variety of virtual diagnostics. Transverse and longitudinal properties are measured upstream of the user area, coupled with the beam optics parameters leading to the user area, and input into a neural network, to predict the same parameters within the user area. Potential instrumentation for FEBE CLARA virtual diagnostics will also be discussed.

Poster MOPORI05 [0.613 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI05

About •

Received ※ 17 August 2022 — Revised ※ 22 August 2022 — Accepted ※ 28 August 2022 — Issue date ※ 01 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPORI06

Improvements on the Modified Nomarski Interferometer for Measurements of Supersonic Gas Jet Density Profiles

235

C. Swain, Ö. Apsimon, A. Salehilashkajani, C.P. Welsch, J. Wolfenden, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Ö. Apsimon, A. Salehilashkajani, C. Swain, C.P. Welsch, J. Wolfenden, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

Funding: This work is supported by the AWAKE-UK phase II project funded by STFC, the STFC Cockcroft core grant No. ST/G008248/1 and the HL-LHC-UK phase II project funded by STFC under Grant Ref: ST/T001925/1.
For supersonic gas jet based beam profile monitors such as that developed for the High Luminosity Large Hadron Collider (HL-LHC) upgrade, density profile is a key characteristic. Due to this, non-invasive diagnostics to study the jet’s behaviour have been designed. A Nomarski interferometer was constructed to image jets 30 um to 1 mm in diameter and study changes in their density. A microscope lens has been integrated into the original interferometer system to capture phase changes on a much smaller scale than previous experiments have achieved. This contribution presents the optimisation and results gained from this interferometer.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-MOPORI06

About •

Received ※ 14 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 29 August 2022 — Issue date ※ 01 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOJO26

Conceptual Design of the PERLE Injector

743

B. Hounsell, M. Klein, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
B. Hounsell, B.L. Militsyn, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B. Hounsell, W. Kaabi
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
B.L. Militsyn
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Energy Recovery Linacs such as PERLE require high average current high brightness beams. This sets particular requirements on the kind of injectors that they can use as the injectors must be capable of producing bunches at MHz repetition rates, compressing the bunches to the specified value and transporting those bunches while they are still in the space charge dominated regime into the main ERL all while keeping the emittance low. In particular, PERLE will require a 20 mA beam consisting of 500 pC bunches with a repetition rate of 40 MHz. These bunches will be required to have rms lengths of 3mm, a total beam energy of 7 MeV, appropriate Twiss parameters to match them to the main loop and transverse emittances of < 6 mm mrad. In this paper, a DC gun based injector capable of meeting this specification will be presented with beam dynamics simulation showing the behaviour of the beam from the photocathode to the exit of the first main linac pass. The beam dynamics challenges will be discussed in terms of both the transverse emittance growth and the sources of non-linearity in the longitudinal phase space.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2022-THPOJO26

About •

Received ※ 20 August 2022 — Revised ※ 24 August 2022 — Accepted ※ 01 September 2022 — Issue date ※ 15 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOOAA02

Welcome to LINAC2022 - Practical Aspects

C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Welcome to LINAC2022 by the Local Organising Committee Chair with an overview of the practical aspects of this week: the ACC conference center, the excursions on Wednesday, and other information.

please see instructions how to view/control embeded videos

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)