IBIC2013 - List of Authors (Gibson, S.M.)

Paper

Title

Page

Beam-line Diagnostics at the Front End Test Stand (FETS), Rutherford Appleton Laboratory, Oxfordshire, UK

431

G.E. Boorman, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
S.R. Lawrie, A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The H⁻ ion source and beam-line at FETS will require the beam current and beam position to be continually monitored. Current transformer toroids will measure the beam current and beam position monitors (BPM) will determine the beam position. The ion source delivers pulses at a rate of 50Hz with a current up to 60mA, each pulse is 2ms long, and a 324MHz micro-bunch structure imposed by the radio frequency quadrapole (RFQ) accelerating structure. The toroid outputs will be acquired on a fast oscilloscope. The BPM design is still under consideration (shorted strip-line or button type) but the processing for both types is similar and has been designed, with simulated measurements made. Each BPM uses four pickups, at a frequency of 324MHz, which are mixed using RF electronics to an intermediate frequency of 10.125MHz. The resulting signals are then digitized at 40.500MHz and processed in an FPGA to produce the position and phase of the beam at each BPM location, with a precision of better than 100μm and 0.05rad. The measurements from the toroids and BPMs will be via EPICS servers at every pulse.

Poster TUPC26 [0.660 MB]

TUPF15

Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators

531

S.M. Gibson, G.E. Boorman, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.

Poster TUPF15 [9.196 MB]

WEPC46

Beam Delivery Simulation (BDSIM): A Geant4 Based Toolkit for Diagnostics and Loss Simulation

799

S.T. Boogert
Royal Holloway, University of London, Surrey, United Kingdom
S.T. Boogert, S.M. Gibson, R. Kwee-Hinzmann, L.J. Nevay, J. Snuverink
JAI, Egham, Surrey, United Kingdom
L.C. Deacon
CERN, Geneva, Switzerland

BDSIM is a Geant4 and C++ based particle tracking code which seamlessly tracks particles in accelerators and particle detectors, including the full range of particle interaction physics processes in Geant4. The code has been used to model the backgrounds in the International Linear Collider (ILC), Compact Linear Collider (CLIC), Accelerator Test Facility 2 (ATF2) and more recently the Large Hadron Collider (LHC). This paper outlines the current code and possible example applications and presents a roadmap for future developments.

TUPF05

Particle Tracking for the FETS Laser Wire Emittance Scanner

503

J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom

The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H⁻ ion beam. The diagnostics of high power particle beams is difficult due to the power deposition on diagnostics elements introduced in the beam so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process utilizing the neutralized particles produced in the interaction between Laser and H⁻ beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.

TUPF14

Description of Laser Transport and Delivery System for the FETS Laserwire Emittance Scanner

527

A. Bosco, G.E. Boorman, S. Emery, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

A beam emittance monitor for H⁻ beams based on laser-induced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). The laser system that will be used for the photo-neutralization of the H⁻ beam is a fiber laser emitting 110 ns pulses at λ=1064nm, with a repetition rate of 30 kHz and peak power of 8 kW. The laser will be conveyed to the interaction area over a distance of 70 m via an optical fiber. An assembly of two remotely controlled motorized translation stages will enable the system to scan across the H⁻ beam along its vertical profile. A motorized beam expander will control the output size of the collimated laser beam in order to enable the system to operate with different spatial characteristics of the ions beam. In this paper we present a full account of the laser characteristics, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber transport efficiency and final delivery laser beam parameters will be reported.

Poster TUPF14 [4.081 MB]

TUPF15

Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators

531

S.M. Gibson, G.E. Boorman, A. Bosco
Royal Holloway, University of London, Surrey, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
JAI, Egham, Surrey, United Kingdom
C. Gabor
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
T. Hofmann
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.

Poster TUPF15 [9.196 MB]

Paper	Title	Page
TUPC26	Beam-line Diagnostics at the Front End Test Stand (FETS), Rutherford Appleton Laboratory, Oxfordshire, UK	431
	G.E. Boorman, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, S.M. Gibson JAI, Egham, Surrey, United Kingdom R.T.P. D'Arcy, S. Jolly UCL, London, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom S.R. Lawrie, A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The H⁻ ion source and beam-line at FETS will require the beam current and beam position to be continually monitored. Current transformer toroids will measure the beam current and beam position monitors (BPM) will determine the beam position. The ion source delivers pulses at a rate of 50Hz with a current up to 60mA, each pulse is 2ms long, and a 324MHz micro-bunch structure imposed by the radio frequency quadrapole (RFQ) accelerating structure. The toroid outputs will be acquired on a fast oscilloscope. The BPM design is still under consideration (shorted strip-line or button type) but the processing for both types is similar and has been designed, with simulated measurements made. Each BPM uses four pickups, at a frequency of 324MHz, which are mixed using RF electronics to an intermediate frequency of 10.125MHz. The resulting signals are then digitized at 40.500MHz and processed in an FPGA to produce the position and phase of the beam at each BPM location, with a precision of better than 100μm and 0.05rad. The measurements from the toroids and BPMs will be via EPICS servers at every pulse.
	Poster TUPC26 [0.660 MB]

TUPF15	Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators	531
	S.M. Gibson, G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.
	Poster TUPF15 [9.196 MB]

WEPC46	Beam Delivery Simulation (BDSIM): A Geant4 Based Toolkit for Diagnostics and Loss Simulation	799
	S.T. Boogert Royal Holloway, University of London, Surrey, United Kingdom S.T. Boogert, S.M. Gibson, R. Kwee-Hinzmann, L.J. Nevay, J. Snuverink JAI, Egham, Surrey, United Kingdom L.C. Deacon CERN, Geneva, Switzerland
	BDSIM is a Geant4 and C++ based particle tracking code which seamlessly tracks particles in accelerators and particle detectors, including the full range of particle interaction physics processes in Geant4. The code has been used to model the backgrounds in the International Linear Collider (ILC), Compact Linear Collider (CLIC), Accelerator Test Facility 2 (ATF2) and more recently the Large Hadron Collider (LHC). This paper outlines the current code and possible example applications and presents a roadmap for future developments.

TUPF05	Particle Tracking for the FETS Laser Wire Emittance Scanner	503
	J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom
	The Front End Test Stand (FETS) is an R&D project at Rutherford Appleton Laboratory (RAL) with the aim to demonstrate a high power (60 mA, 3 MeV with 50 pps and 10 % duty cycle), fast chopped H⁻ ion beam. The diagnostics of high power particle beams is difficult due to the power deposition on diagnostics elements introduced in the beam so non-invasive instrumentation is highly desirable. The laser wire emittance scanner under construction is based on a photo-detachment process utilizing the neutralized particles produced in the interaction between Laser and H⁻ beam for beam diagnostics purposes. The principle is appropriate to determine the transversal beam density distribution as well as the transversal and longitudinal beam emittance behind the RFQ. The instrument will be located at the end of the MEBT with the detachment taking place inside a dipole field. Extensive particle tracking simulations have been performed for various settings of the MEBT quadrupoles to investigate the best placement and size of the 2D scintillating detector and to determine the range and resolution of the instrument. Additionally the power distribution in the following beam dumps has been determined.

TUPF14	Description of Laser Transport and Delivery System for the FETS Laserwire Emittance Scanner	527
	A. Bosco, G.E. Boorman, S. Emery, S.M. Gibson Royal Holloway, University of London, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	A beam emittance monitor for H⁻ beams based on laser-induced ions neutralization is being developed at the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL). The laser system that will be used for the photo-neutralization of the H⁻ beam is a fiber laser emitting 110 ns pulses at λ=1064nm, with a repetition rate of 30 kHz and peak power of 8 kW. The laser will be conveyed to the interaction area over a distance of 70 m via an optical fiber. An assembly of two remotely controlled motorized translation stages will enable the system to scan across the H⁻ beam along its vertical profile. A motorized beam expander will control the output size of the collimated laser beam in order to enable the system to operate with different spatial characteristics of the ions beam. In this paper we present a full account of the laser characteristics, the optical transport system and the final delivery assembly. All the relevant measurements such as power, spatial and temporal characteristics of the laser, fiber transport efficiency and final delivery laser beam parameters will be reported.
	Poster TUPF14 [4.081 MB]

TUPF15	Overview of Laserwire Beam Profile and Emittance Measurements for High Power Proton Accelerators	531
	S.M. Gibson, G.E. Boorman, A. Bosco Royal Holloway, University of London, Surrey, United Kingdom G.E. Boorman, A. Bosco, S.M. Gibson JAI, Egham, Surrey, United Kingdom C. Gabor STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom T. Hofmann CERN, Geneva, Switzerland A.P. Letchford STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski, P. Savage Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Laserwires were originally developed to measure micron-sized electron beams via Compton scattering, where traditional wire scanners are at the limit of their resolution. Laserwires have since been applied to larger beam-size, high power H⁻ ion beams, where the non-invasive method can probe beam densities that would damage traditional diagnostics. While photo-detachment of H⁻ ions is now routine to measure beam profiles, extending the technique to transverse and longitudinal emittance measurements is a key aim of the laserwire emittance scanner under construction at the Front End Test Stand (FETS) at the RAL. A pulsed, 30kHz, 8kW peak power laser is fibre-coupled to motorized collimating optics, which controls the position and thickness of the laserwire delivered to the H⁻ interaction chamber. The laserwire slices out a beamlet of neutralized particles, which propagate to a downstream scintillator and camera. The emittance is reconstructed from 2D images as the laserwire position is scanned. Results from the delivery optics, scintillator tests and particle tracking simulations of the full system are reviewed. Plans to deploy the FETS laser system at the Linac4 at CERN are outlined.
	Poster TUPF15 [9.196 MB]