HB2012 - List of Keywords (controls)

Paper	Title	Other Keywords	Page
MOP211	1-MW Beam Operation Scenario in the J-PARC RCS	injection, quadrupole, emittance, lattice	68
	H. Hotchi, H. Harada, N. Hayashi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie KEK, Ibaraki, Japan
	The injection energy of the J-PARC RCS will be upgraded from 181 MeV to 400 MeV in the 2013 summer-autumn period. With this upgraded injection energy, we are to aim for 1 MW design output beam power. In this paper, we discuss beam dynamics issues for the 1 MW beam operation and their possible solutions.

MOP214	Test System and Characteristics Studies of Ferrite Cores for the CSNS RCS RF System	cavity, impedance, power-supply, LLRF	81
	H. Shi, W.L. Huang, X. Li, W. Long, H. Sun, J.Y. Tang, C.L. Zhang IHEP, Beijing, People's Republic of China
	A two-ring ferrite test system for ferrite-loaded cavities of Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) has been developed. By this system, the RF characteristics of full-sized ferrite cores of RCS cavities have been studied. On dc bias current, the swept frequency range and thresholds of High Loss Effect (HLE) have been presented. On ac bias current of 25 Hz, although the shunt impedance of the cores satisfies the CSNS cavity, comparing with the dc bias, more power dissipation and more required bias current have been observed because the induced magnetic anisotropy of the ferrite cores disappears. Consequently, it is important to evaluate the dynamic features of the cores with 25 Hz bias current for designing the cavities, the power supplies and the bias current sources.

MOP223	Radiation Safety System for PKUNIFTY Project	neutron, radiation, shielding, power-supply	112
	J. Zhao, J.E. Chen, Z.Y. Guo, Y.R. Lu, S.X. Peng PKU, Beijing, People's Republic of China J. Zhao, Q.F. Zhou State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China
	PKUNIFTY (Peking University Neutron Imaging FaciliTY) , which is based on a 2 MeV RFQ accelerator-driven compact neutron sourse with an expected fast-neutron yield of 2.9*1012n/s via the deuteron-beryllium reaction, has been operated this year. A radiation safety system for PKUNIFTY, that protects personnel from radiation hazards has been built and run since last year, is described. It consists of a shielding optimized with Monte-Carlo simulation, a dose interlock system, an alternative interlock with another 4.5MV tandem accelerator facility, and a video monitoring system. The dose of supervision area is less than 0.5μSv/h during beam operation.

MOP238	Beam Position Monitor System of the ESS Linac	linac, LLRF, quadrupole, target	133
	H. Hassanzadegan, A. Jansson ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden
	The pulsed ESS linac will include about 100 BPMs, mostly with a European XFEL style button design, 6 BPMs with a special design for the Medium Energy Beam Transport, as well as 8 stripline BPMs foreseen for the Drift Tubes. The required accuracy and resolution of the position measurement are 100 μm (rms) and 20 μm (rms) respectively with the 50 mA 2.86 ms nominal pulse. In addition to the position measurement, the BPM system needs to measure the beam phase in the nominal pulse as well as several diagnostics pulse modes with a minimum duration and intensity of 5 μs and 5 mA respectively. After a study of the possible electronics platforms, MTCA.4 is now considered as the main prototyping platform for the high performance sub-systems at ESS. It is foreseen to prototype a Rear Transition Module for IQ-based RF signal measurements intended for both the BPM and LLRF systems. The requirements and specifications of the BPM system are presented and the plan for the continuation of the project is described in this paper.

MOP247	Beam Stability and Tail Population at SPS Scrapers	emittance, injection, extraction, diagnostics	166
	L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Mikulec, E. Veyrunes CERN, Geneva, Switzerland
	Before injection into the LHC the beams are scraped in the SPS to remove the tails of the transverse particle distributions. Without scraping the tail population is large enough to create losses above the beam abort thresholds of the LHC beam loss monitor system when injecting. The scrapers are only effective if correctly set up. This paper shows the results of periodical scraper scans. The beam position and beam size at the scraper is changing with time. The scraper settings hence need to follow accordingly. The scans also give insight into the transverse tail population and could therefore provide useful beam quality diagnostics. The impact on new scraper designs and setting up strategy are discussed.

TUO3C02	FNAL Proton Source High Intensity Operations and Beam Loss Control	booster, proton, cavity, injection	320
	F.G.G. Garcia, W. Pellico Fermilab, Batavia, USA
	Funding: U.S. Department of Energy The Proton Source (PS) has been the workhorse of the Fermi National Accelerator Laboratory (FNAL) for over 40 years. During that time the United States High Energy Physics program has continued to change with increasing demands put on the PS. The past 10 years saw an increase of over 10 fold in required hourly flux for the PS and plans are now underway to have the capability to double the output with continued operations until at least 2025. To meet these goals, effort in area of beam loss control has been a major part of the upgrades. Beam collimation and absorption systems as well as diagnostics used to mitigate and control losses have been implemented. The recent implementation of new correctors for orbit and higher harmonic control has also been very beneficial. A summary of recent and planned modification to these PS systems will be discussed.
	Slides TUO3C02 [16.766 MB]

WEO1A04	Longitudinal Instabilities in the SPS and Beam Dynamics Issues with High Harmonic RF Systems	emittance, beam-loading, synchrotron, damping	358
	E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, J. Esteban Müller, H. Timko CERN, Geneva, Switzerland
	Even after a successful impedance reduction programme which eliminated the microwave instability in the SPS another longitudinal instability is still one of the main intensity limitations. It is observed during acceleration ramp for both single bunch and multibunch beams at intensities below the nominal LHC intensity. With the lower transition energy of the new SPS optics, under intensive studies now, the thresholds are increased. However, even in this case the operation of the 4th harmonic RF system is required for stability of the nominal beams. To cope with the higher intensity beams required for the future High Luminosity LHC an upgrade program for both RF systems is under way. The results of studies of the parameter space required for beam stability are presented and compared with operation modes of double RF systems in other accelerators.
	Slides WEO1A04 [6.135 MB]

WEO3A01	High Energy Electron Cooling	electron, high-voltage, vacuum, gun	363
	V.B. Reva, M.I. Bryzgunov, V.M. Panasyuk, V.V. Parkhomchuk BINP SB RAS, Novosibirsk, Russia
	The electron cooler of a 2 MeV for COSY storage ring FZJ is assembled in BINP. This paper describes the first experimental results from the electron cooler with electron beam and high voltage. The cooling section is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.1(0.025)-2 MeV. The electrostatic accelerator consists of 34 individual unify section. Each section contains two HV power supply (±30 kV) and power supply of the magnetic coils. The electrical power to each section is provided by the cascade transformer. The cascade transformer is the set of the transformer connected in series with isolating winding.
	Slides WEO3A01 [7.902 MB]

WEO3B05	Using Step-Like Nonlinear Magnets for Beam Uniformization at IFMIF Target	target, neutron, multipole, octupole	424
	Z. Yang, J.Y. Tang IHEP, Beijing, People's Republic of China N. Chauvin, P.A.P. Nghiem CEA/DSM/IRFU, France
	Uniform beam distribution and minimum beam halo on target are often required in high intensity beam applications to prolong the target lifetime, ease cooling and obtain better irradiation effect. In this report, step-like nonlinear magnets instead of standard multipole magnets have been studied for the application at IFMIF. Although the preliminary results are still below the very critical requirement of spot uniformity at the IFMIF target, they are quite permissive. The method demonstrates significant advantages over the conventional combination of octupole and duodecapole on very low beam loss, better uniformity and very low cost. Further studies are needed to fully meet the IFMIF specifications.
	Slides WEO3B05 [1.487 MB]

WEO3C03	Beam Halo Dynamics and Control with Hollow Electron Beams	electron, collimation, collider, emittance	466
	G. Stancari, G. Annala, A. Didenko, T.R. Johnson, I.A. Morozov, V. Previtali, G.W. Saewert, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev Fermilab, Batavia, USA R.W. Aßmann, R. Bruce, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino CERN, Geneva, Switzerland D.N. Shatilov BINP SB RAS, Novosibirsk, Russia
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the US Department of Energy. Partial support was provided by the US LHC Accelerator Research Program (LARP). Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.
	Slides WEO3C03 [5.139 MB]

WEO3C06	Understanding Ion Induced Radiation Damage in Target Materials	target, ion, heavy-ion, radiation	476
	M. Tomut, C.L. Hubert GSI, Darmstadt, Germany M. Tomut INFIM, Bucharest, Romania
	Successful operation of next generations of radioactive beam facilities depends on the target survival in conditions of intense radiation field and thermo-mechanical solicitations induced by the driving ion beam. Material property degradation due to ion- beam induced damage will limit target lifetime, either by affecting target performance or, by reducing the material resilience. Similar problems are faced by beam protection elements at LHC. Understanding the mechanism of radiation damage induced by ion beam in these materials provides valuable knowledge for lifetime prediction and for the efforts to mitigate performance degradation. On their way through the target material, energetic heavy ions induce a trail of ionizations and excitations, resulting in formation of ion tracks consisting of complex defect structures. We give a review on the ion-induced damage creation in high power target materials, on the structural and thermo-mechanical property degradation and on their recovery in high temperature irradiation experiments.
	Slides WEO3C06 [4.439 MB]

THO1B05	Broad-band Transverse Feedback against e-cloud or TMCI: Plan and Status	feedback, kicker, electron, pick-up	527
	C.H. Rivetta, J.M. Cesaratto, J.D. Fox, M.T.F. Pivi, O. Turgut, S. Uemura SLAC, Menlo Park, California, USA W. Höfle, K.S.B. Li CERN, Geneva, Switzerland
	The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling (Transverse mode coupled instabilities, TMCI) requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. To develop the feedback control prototype, different research areas have been pursed to model and identify the bunch dynamics, design the feedback control and implement the GigaHertz bandwidth hardware. This paper presents those R&D lines and reports on the progress as it stands today. It presents preliminary results of feedback systems stabilizing the transverse intra-bunch motion, based on macro-particle simulation codes (CMAD / HeadTail) and measurement results of the beam motion when it is driven by particular excitation signals.
	Slides THO1B05 [7.197 MB]

THO1C02	Beam Loss Control in the ISIS Accelerator Facility	injection, synchrotron, proton, acceleration	560
	D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.
	Slides THO1C02 [4.759 MB]

Paper

Title

Other Keywords

Page

MOP211

1-MW Beam Operation Scenario in the J-PARC RCS

injection, quadrupole, emittance, lattice

68

H. Hotchi, H. Harada, N. Hayashi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie
KEK, Ibaraki, Japan

The injection energy of the J-PARC RCS will be upgraded from 181 MeV to 400 MeV in the 2013 summer-autumn period. With this upgraded injection energy, we are to aim for 1 MW design output beam power. In this paper, we discuss beam dynamics issues for the 1 MW beam operation and their possible solutions.

MOP214

Test System and Characteristics Studies of Ferrite Cores for the CSNS RCS RF System

cavity, impedance, power-supply, LLRF

81

H. Shi, W.L. Huang, X. Li, W. Long, H. Sun, J.Y. Tang, C.L. Zhang
IHEP, Beijing, People's Republic of China

A two-ring ferrite test system for ferrite-loaded cavities of Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) has been developed. By this system, the RF characteristics of full-sized ferrite cores of RCS cavities have been studied. On dc bias current, the swept frequency range and thresholds of High Loss Effect (HLE) have been presented. On ac bias current of 25 Hz, although the shunt impedance of the cores satisfies the CSNS cavity, comparing with the dc bias, more power dissipation and more required bias current have been observed because the induced magnetic anisotropy of the ferrite cores disappears. Consequently, it is important to evaluate the dynamic features of the cores with 25 Hz bias current for designing the cavities, the power supplies and the bias current sources.

MOP223

Radiation Safety System for PKUNIFTY Project

neutron, radiation, shielding, power-supply

112

J. Zhao, J.E. Chen, Z.Y. Guo, Y.R. Lu, S.X. Peng
PKU, Beijing, People's Republic of China
J. Zhao, Q.F. Zhou
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

PKUNIFTY (Peking University Neutron Imaging FaciliTY) , which is based on a 2 MeV RFQ accelerator-driven compact neutron sourse with an expected fast-neutron yield of 2.9*1012n/s via the deuteron-beryllium reaction, has been operated this year. A radiation safety system for PKUNIFTY, that protects personnel from radiation hazards has been built and run since last year, is described. It consists of a shielding optimized with Monte-Carlo simulation, a dose interlock system, an alternative interlock with another 4.5MV tandem accelerator facility, and a video monitoring system. The dose of supervision area is less than 0.5μSv/h during beam operation.

MOP238

Beam Position Monitor System of the ESS Linac

linac, LLRF, quadrupole, target

133

H. Hassanzadegan, A. Jansson
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden

The pulsed ESS linac will include about 100 BPMs, mostly with a European XFEL style button design, 6 BPMs with a special design for the Medium Energy Beam Transport, as well as 8 stripline BPMs foreseen for the Drift Tubes. The required accuracy and resolution of the position measurement are 100 μm (rms) and 20 μm (rms) respectively with the 50 mA 2.86 ms nominal pulse. In addition to the position measurement, the BPM system needs to measure the beam phase in the nominal pulse as well as several diagnostics pulse modes with a minimum duration and intensity of 5 μs and 5 mA respectively. After a study of the possible electronics platforms, MTCA.4 is now considered as the main prototyping platform for the high performance sub-systems at ESS. It is foreseen to prototype a Rear Transition Module for IQ-based RF signal measurements intended for both the BPM and LLRF systems. The requirements and specifications of the BPM system are presented and the plan for the continuation of the project is described in this paper.

MOP247

Beam Stability and Tail Population at SPS Scrapers

emittance, injection, extraction, diagnostics

166

L.N. Drøsdal, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, O. Mete, B. Mikulec, E. Veyrunes
CERN, Geneva, Switzerland

Before injection into the LHC the beams are scraped in the SPS to remove the tails of the transverse particle distributions. Without scraping the tail population is large enough to create losses above the beam abort thresholds of the LHC beam loss monitor system when injecting. The scrapers are only effective if correctly set up. This paper shows the results of periodical scraper scans. The beam position and beam size at the scraper is changing with time. The scraper settings hence need to follow accordingly. The scans also give insight into the transverse tail population and could therefore provide useful beam quality diagnostics. The impact on new scraper designs and setting up strategy are discussed.

TUO3C02

FNAL Proton Source High Intensity Operations and Beam Loss Control

booster, proton, cavity, injection

320

F.G.G. Garcia, W. Pellico
Fermilab, Batavia, USA

Funding: U.S. Department of Energy
The Proton Source (PS) has been the workhorse of the Fermi National Accelerator Laboratory (FNAL) for over 40 years. During that time the United States High Energy Physics program has continued to change with increasing demands put on the PS. The past 10 years saw an increase of over 10 fold in required hourly flux for the PS and plans are now underway to have the capability to double the output with continued operations until at least 2025. To meet these goals, effort in area of beam loss control has been a major part of the upgrades. Beam collimation and absorption systems as well as diagnostics used to mitigate and control losses have been implemented. The recent implementation of new correctors for orbit and higher harmonic control has also been very beneficial. A summary of recent and planned modification to these PS systems will be discussed.

Slides TUO3C02 [16.766 MB]

WEO1A04

Longitudinal Instabilities in the SPS and Beam Dynamics Issues with High Harmonic RF Systems

emittance, beam-loading, synchrotron, damping

358

E.N. Shaposhnikova, T. Argyropoulos, T. Bohl, J. Esteban Müller, H. Timko
CERN, Geneva, Switzerland

Even after a successful impedance reduction programme which eliminated the microwave instability in the SPS another longitudinal instability is still one of the main intensity limitations. It is observed during acceleration ramp for both single bunch and multibunch beams at intensities below the nominal LHC intensity. With the lower transition energy of the new SPS optics, under intensive studies now, the thresholds are increased. However, even in this case the operation of the 4th harmonic RF system is required for stability of the nominal beams. To cope with the higher intensity beams required for the future High Luminosity LHC an upgrade program for both RF systems is under way. The results of studies of the parameter space required for beam stability are presented and compared with operation modes of double RF systems in other accelerators.

Slides WEO1A04 [6.135 MB]

WEO3A01

High Energy Electron Cooling

electron, high-voltage, vacuum, gun

363

V.B. Reva, M.I. Bryzgunov, V.M. Panasyuk, V.V. Parkhomchuk
BINP SB RAS, Novosibirsk, Russia

The electron cooler of a 2 MeV for COSY storage ring FZJ is assembled in BINP. This paper describes the first experimental results from the electron cooler with electron beam and high voltage. The cooling section is designed on the classic scheme of low energy coolers like cooler CSRm, CSRe, LEIR that was produced in BINP before. The electron beam is transported inside the longitudinal magnetic field along whole trajectory from an electron gun to a collector. This optic scheme is stimulated by the wide range of the working energies 0.1(0.025)-2 MeV. The electrostatic accelerator consists of 34 individual unify section. Each section contains two HV power supply (±30 kV) and power supply of the magnetic coils. The electrical power to each section is provided by the cascade transformer. The cascade transformer is the set of the transformer connected in series with isolating winding.

Slides WEO3A01 [7.902 MB]

WEO3B05

Using Step-Like Nonlinear Magnets for Beam Uniformization at IFMIF Target

target, neutron, multipole, octupole

424

Z. Yang, J.Y. Tang
IHEP, Beijing, People's Republic of China
N. Chauvin, P.A.P. Nghiem
CEA/DSM/IRFU, France

Uniform beam distribution and minimum beam halo on target are often required in high intensity beam applications to prolong the target lifetime, ease cooling and obtain better irradiation effect. In this report, step-like nonlinear magnets instead of standard multipole magnets have been studied for the application at IFMIF. Although the preliminary results are still below the very critical requirement of spot uniformity at the IFMIF target, they are quite permissive. The method demonstrates significant advantages over the conventional combination of octupole and duodecapole on very low beam loss, better uniformity and very low cost. Further studies are needed to fully meet the IFMIF specifications.

Slides WEO3B05 [1.487 MB]

WEO3C03

Beam Halo Dynamics and Control with Hollow Electron Beams

electron, collimation, collider, emittance

466

G. Stancari, G. Annala, A. Didenko, T.R. Johnson, I.A. Morozov, V. Previtali, G.W. Saewert, V.D. Shiltsev, D.A. Still, A. Valishev, L.G. Vorobiev
Fermilab, Batavia, USA
R.W. Aßmann, R. Bruce, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract DE-AC02-07CH11359 with the US Department of Energy. Partial support was provided by the US LHC Accelerator Research Program (LARP).
Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.

Slides WEO3C03 [5.139 MB]

WEO3C06

Understanding Ion Induced Radiation Damage in Target Materials

target, ion, heavy-ion, radiation

476

M. Tomut, C.L. Hubert
GSI, Darmstadt, Germany
M. Tomut
INFIM, Bucharest, Romania

Successful operation of next generations of radioactive beam facilities depends on the target survival in conditions of intense radiation field and thermo-mechanical solicitations induced by the driving ion beam. Material property degradation due to ion- beam induced damage will limit target lifetime, either by affecting target performance or, by reducing the material resilience. Similar problems are faced by beam protection elements at LHC. Understanding the mechanism of radiation damage induced by ion beam in these materials provides valuable knowledge for lifetime prediction and for the efforts to mitigate performance degradation. On their way through the target material, energetic heavy ions induce a trail of ionizations and excitations, resulting in formation of ion tracks consisting of complex defect structures. We give a review on the ion-induced damage creation in high power target materials, on the structural and thermo-mechanical property degradation and on their recovery in high temperature irradiation experiments.

Slides WEO3C06 [4.439 MB]

THO1B05

Broad-band Transverse Feedback against e-cloud or TMCI: Plan and Status

feedback, kicker, electron, pick-up

527

C.H. Rivetta, J.M. Cesaratto, J.D. Fox, M.T.F. Pivi, O. Turgut, S. Uemura
SLAC, Menlo Park, California, USA
W. Höfle, K.S.B. Li
CERN, Geneva, Switzerland

The feedback control of intra-bunch instabilities driven by electron-clouds or strong head-tail coupling (Transverse mode coupled instabilities, TMCI) requires bandwidth sufficient to sense the vertical position and apply multiple corrections within a nanosecond-scale bunch. These requirements impose challenges and limits in the design and implementation of the feedback system. To develop the feedback control prototype, different research areas have been pursed to model and identify the bunch dynamics, design the feedback control and implement the GigaHertz bandwidth hardware. This paper presents those R&D lines and reports on the progress as it stands today. It presents preliminary results of feedback systems stabilizing the transverse intra-bunch motion, based on macro-particle simulation codes (CMAD / HeadTail) and measurement results of the beam motion when it is driven by particular excitation signals.

Slides THO1B05 [7.197 MB]

THO1C02

Beam Loss Control in the ISIS Accelerator Facility

injection, synchrotron, proton, acceleration

560

D.J. Adams, B. Jones, A.H. Kershaw, S.J. Payne, B.G. Pine, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam lines. The facility currently delivers ~2.8·10¹³ protons per pulse at 50 Hz, splitting the pulses 40/10 between two neutron target stations. High intensity performance and operation are dominated by the need to control beam loss, which is key to sustainable machine operation and hands on maintenance. Beam loss measurement systems on ISIS are described, along with typical operational levels. The dominant beam loss in the facility occurs in the synchrotron due to high intensity effects during the H⁻ injection and longitudinal trapping processes. These losses are localised in a single superperiod using a beam collector system. Emittance growth during acceleration also drives extraction and beam transport loss at 800 MeV. Measurements, simulation and correction systems for these processes are discussed, as are the implications for further intensity upgrades.

Slides THO1C02 [4.759 MB]