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The CERN-MEDICIS (MEDical Isotopes Collected from ISolde) facility has delivered its first radioactive ion beam at CERN (Switzerland) in December 2017 to support the research and development in nuclear medicine using non-conventional radionuclides. Since then, fourteen institutes, including CERN, have joined the collaboration to drive the scientific program of this unique installation and evaluate the needs of the community to improve the research in imaging, diagnostics, radiation therapy and personalized medicine. The facility has been built as an extension of the ISOLDE (Isotope Separator On Line DEvice) facility at CERN. Handling of open radioisotope sources is made possible thanks to its Radiological Controlled Area and laboratory. Targets are being irradiated by the 1.4 GeV proton beam delivered by the CERN Proton Synchrotron Booster (PSB) on a station placed between the High Resolution Separator (HRS) ISOLDE target station and its beam dump. Irradiated target materials are also received from external institutes to undergo mass separation at CERN-MEDICIS. All targets are handled via a remote handling system and exploited on a dedicated isotope separator beamline. To allow for the release and collection of a specific radionuclide of medical interest, each target is heated to temperatures of up to 2,300°C. The created ions are extracted and accelerated to an energy up to 60 kV, and the beam steered through an off-line sector field magnet mass separator. This is followed by the extraction of the radionuclide of interest through mass separation and its subsequent implantation into a collection foil. In addition, the MELISSA (MEDICIS Laser Ion Source Setup At CERN) laser laboratory, in service since April 2019, helps to increase the separation efficiency and the selectivity. After collection, the implanted radionuclides are dispatched to the biomedical research centers, participating in the CERN-MEDICIS collaboration, for Research & Development in imaging or treatment. Since its commissioning, the CERN-MEDICIS facility has provided its partner institutes with non-conventional medical radionuclides such as Tb-149, Tb-152, Tb-155, Sm-153, Tm-165, Tm-167, Er-169, Yb-175, and Ac-225 with a high specific activity. This article provides a review of the achievements and milestones of CERN-MEDICIS since it has produced its first radioactive isotope in December 2017, with a special focus on its most recent operation in 2020. ispartof: FRONTIERS IN MEDICINE vol:8 ispartof: location:Switzerland status: published

In synchrotrons at the European Organization for Nuclear Research (CERN), magnetic measurement systems known as B-trains measure the magnetic field in the main bending magnets in real-time, and transmit this signal for the control of the synchrotron’s RF accelerating cavities, magnet power converter and beam monitoring systems. This work presents an assessment of the capabilities and performance of the new FIRESTORM (Field In REal-time STreaming from Online Reference Magnets) system as part of the first phase of commissioning. A short summary of the architecture of the measurement system is provided first, followed by the definition of an error model which can be used to characterize random and systematic errors separately. We present a procedure for the metrological calibration and qualification of the B-trains, including an experimental evaluation of the different error sources for the four new systems being commissioned in the Proton Synchrotron Booster (PSB), Low Energy Ion Ring (LEIR), Proton Synchrotron (PS) and the Extra Low ENergy Antiproton (ELENA) ring. In particular, we discuss a method to calibrate systematic gain and offset errors based on the RF cavity frequency offset needed to center the beam on its theoretical orbit.

A new beam dump has been designed, built, installed and operated to withstand the future proton beam extracted from the proton synchrotron booster (PSB) in the framework of the LHC Injector Upgrade (LIU) Project at CERN. The future proton beam consists of up to 1×1014 protons per pulse at 2 GeV and is foreseen after the machine upgrades planned for CERN’s Long Shutdown 2 (2019-2020). In order to be able to efficiently dissipate the heat deposited by the primary beam, the new dump was designed as a cylindrical block assembly, made out of a copper alloy and cooled by forced airflow. In order to determine the energy density distribution deposited by the beam in the dump, Monte Carlo simulations were performed using the fluka code, and thermomechanical analyses were carried out by importing the energy density into ANSYS®. In addition, computational fluid dynamics (CFD) simulations of the airflow were performed in order to accurately estimate the heat transfer convection coefficient on the surface of the dump. This paper describes the design process, highlights the constraints and challenges of integrating a new dump for increased beam power into the existing facility and provides data on the operation of the dump. A new beam dump has been designed, built, installed and operated to withstand the future proton beam extracted from the Proton Synchrotron Booster (PSB) in the framework of the LHC Injector Upgrade (LIU) Project at CERN, consisting of up to 1E14 protons per pulse at 2 GeV, foreseen after the machine upgrades planned for CERN's Long Shutdown 2 (2019-2020). In order to be able to efficiently dissipate the heat deposited by the primary beam, the new dump was designed as a cylindrical block assembly, made out of a copper alloy and cooled by forced airflow. In order to determine the energy density distribution deposited by the beam in the dump, Monte Carlo simulations were performed using the FLUKA code, and thermo-mechanical analyses were carried out by importing the energy density into ANSYS. In addition, Computational Fluid Dynamics (CFD) simulations of the airflow were performed in order to accurately estimate the heat transfer convection coefficient on the surface of the dump. This paper describes the design process, highlights the constraints and challenges of integrating a new dump for increased beam power into the existing facility and provides data on the operation of the dump.

Integrator drift is a problem strongly felt in different measurement fields, often detrimental even for short-term applications. An analytical method for modelling and feed-forward correcting drift in magnetic flux measurements was developed analytically and tested experimentally. A case study is reported on the proof of principle as a novel kind of quasi-DC field marker of the 5-ppm Nuclear Magnetic Resonance (NMR) transducer Metrolab PT2026, applied to the Extra Low ENergy Antiproton (ELENA) ring and the Proton Synchrotron Booster (PSB) at CERN. In some particle accelerators, such as in ELENA, the resulting feed-forward correction guarantees 1 μ T field stability over 120-s long magnetic cycle on a plateau of 50 mT, reducing by three orders of magnitude the field error caused by the integrator drift with respect to the state of the art.

International audience; In this paper, we report on the development and first deployment of a distributed optical fiber radiation sensor (DOFRS) for the online monitoring of radiation levels in the high-energy accelerator facilities of CERN. The DOFRS is composed of two basic parts: a set of suitably chosen radiation sensitive optical fibers (OFs), to be installed in the machine tunnel, and an optical time domain reflectometer (OTDR), to be installed in a radiation-free area. We carried out a calibration of the radiation response of a P-doped multimode OF under $^{60}$Co $\gamma$-rays and in the mixed-field radiation environment of the CHARM facility at CERN. By performing OTDR measurements, we are able to probe the radiation-induced attenuation in the OF along its length and calculate the deposited radiation dose with a spatial resolution of 1 m. In this paper, we describe the main features associated with DOFRS implementation in the proton synchrotron booster (PSB) at CERN. We also report the first results obtained from the monitoring of PSB radiation levels since its recommissioning in April 2017. The performances and advantages of the DOFRS system are discussed.

As part of the LHC Injector Upgrade (LIU) project, the production of a high-intensity proton beam in the Proton Synchrotron Booster (PSB) at CERN will be achieved by injecting a beam of H− ions from the new linear accelerator LINAC4. During the injection process the two electrons of the H− ions are removed with a stripping foil across which the machine orbit is shifted to fill the machine aperture with beam. The process of filling the machine aperture is called ‘phase space painting’ and is accomplished with four individually-pulsed ferrite-cored kicker magnets. The magnets, two of 36μH inductance and two of 320μH inductance, will be excited by piecewise linearly decreasing currents with a maximum current of 400A for the 36μH magnets. The waveforms will comprise four different programmable slopes, changeable from pulse to pulse in the range of 8μs to 150μs. The four kicker waveforms must be well synchronized and deviate less than 0.5% from a reference waveform. Each pulse generator contains several stages of pre-charged capacitors that one after another are switched to the magnet to generate the current with the required slopes; additional stages are present to allow fine control of the slope linearity. The performance of the first operational prototype is presented and compared to theoretical calculations.

High precision modeling of space-charge effects, together with accurate treatment of single-particle dynamics, is essential for designing future accelerators as well as optimizing the performance of existing machines. We describe Synergia, a high-fidelity parallel beam dynamics simulation package with fully three-dimensional space-charge capabilities and a higher order optics implementation. We describe the computational techniques, the advanced human interface, and the parallel performance obtained using large numbers of macroparticles. We also perform code benchmarks comparing to semi-analytic results and other codes. Finally, we present initial results on particle tune spread, beam halo creation, and emittance growth in the Fermilab Booster accelerator.

In addition to heavy ion collisions (RHIC Design Manual, Brookhaven National Laboratory), RHIC will also collide intense beams of polarized protons (I. Alekseev, et al., Design Manual Polarized Proton Collider at RHIC, Brookhaven National Laboratory, 1998 [2]), reaching transverse energies where the protons scatter as beams of polarized quarks and gluons. The study of high energy polarized protons beams has been a long term part of the program at BNL with the development of polarized beams in the Booster and AGS rings for fixed target experiments. We have extended this capability to the RHIC machine. In this paper we describe the design and methods for achieving collisions of both longitudinal and transverse polarized protons in RHIC at energies up to s =500 GeV .

The construction of a compact rapid cycling synchrotron has recently been studied at CERN to replace the first stage of its accelerator complex, the proton synchrotron booster. Although currently there are no plans to build this machine, fast cycled accelerator magnets are of general interest for numerous reasons. This has led to the design, manufacture, and testing of a scaled model dipole as detailed in this paper to show the capability of producing and characterizing a magnet design based on high-silicon content grain-oriented steel able to operate up to 1.3 T at 10 Hz.

Since its first operation in 1972 at an energy of 800 MeV, the CERN Proton Synchrotron Booster, which consists of four superimposed synchrotrons, has seen two upgrades: once to 1.0 GeV in 1988 and then to 1.4 GeV in 1999. During this time the main magnets of the machine have remained largely unchanged with small differences (1%) between the inner and outer gaps of the main bending magnet fields being compensated by trim power supplies. The future upgrade of the machine will demand to extract protons at an energy of 2.0 GeV and require almost double the original dipole field. At this field, due to saturation effects, the inner and outer gaps of the main dipole magnets will differ by up to 4%. This paper presents the design and implementation of a modification of the magnetic circuit strongly reducing these effects. We also discuss the results of experimental tests concerning the effects on field quality and eddy current transients, including the implications for the real-time magnetic field measurement system to control RF and power supplies.

Linac4 is the first element of the Large Hadron Collider Injectors Upgrade Project and will replace the existing Linac2 as linear injector of protons for the CERN accelerators. A new transfer line will link Linac4 to the Proton Synchrotron Booster. Approximately a hundred normal-conducting electro-magnets are required for beam steering and focusing along the linac and the transfer line. This text concentrates on the design of the Linac4 quadrupole magnets. The design and the first magnetic measurements of the inter-tank quadrupole electro-magnets are discussed. In addition, the design and optimization of the transfer line quadrupole magnets are highlighted. The compatibility of the magnetic requirements and the power converter constraints for the latter magnet type is assessed.

The LHC Injector Upgrade (LIU) project aims to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Starting at the source a H- beam is accelerated by LINAC4 and then injected into the Proton Synchrotron Booster (PSB). During injection the two electrons of the H- ions are removed with a stripping foil. The protons produced in this way are then accelerated successively by the PSB, the PS and the SPS before being injected into the LHC. When the H-beam is injected into the PSB the machine orbit is shifted across the stripping foil to fill the machine aperture with beam. This shifting of orbit is called `painting' and is accomplished with four slow kicker magnets. The kickers must be well synchronized and with less than 0.5% of deviation from a reference waveform. These kicker magnets will operate with a maximum current of 400A and will have waveforms comprising four different programmable slopes, changeable from pulse to pulse in the range of 10μs to 100μs. Each kicker will be energized by a pulse generator which contains several stages of pre-charged capacitors that one after another are switched to the magnet to generate the current with the required slopes. Additional stages are present to allow fine control of the slope linearity.

The new linear accelerator (Linac4) under construction at CERN [1] is designed to provide a 160MeV negative hydrogen ions (H-) beam to the Proton Synchrotron Booster (PSB). Linac4 is intended to replace the ageing 50MeV Linac2 and aims to increase the LHC beam luminosity. Several H-sources are under development [2] in view of gradually increasing the H-intensity to 80 mA with a limited co-extracted electron beam of 1-1.5 A. Previous attempts to reach this H-beam intensity showed the necessity of replacing the source's high voltage DC power supplies with high voltage pulsed power converters, with the objective of mitigating destructive arc events inside the source between two RF pulses (beam extraction length of 700 μs with 2 Hz repetition rate).

The LHC Injector Upgrade (LIU) project aims to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Starting at the source a H- beam is accelerated by LINAC4 and then injected into the Proton Synchrotron Booster (PSB). During injection the two electrons of the H- ions are removed with a stripping foil. The protons produced in this way are then accelerated successively by the PSB, the PS and the SPS before being injected into the LHC. When the H- beam is injected into the PSB the machine orbit is shifted across the stripping foil to fill the machine aperture with beam. This shifting of orbit is called `painting' and is accomplished with four slow kicker magnets. The kickers must be well synchronized and deviate less than 0.5% from a reference waveform. They will operate with a maximum current of 400A and will have waveforms comprising four different programmable slopes, changeable from pulse to pulse in the range of 10μs to 100μs. Each kicker will be energized by a pulse generator which contains several stages of pre-charged capacitors that one after another are switched to the magnet to generate the current with the required slopes. Additional stages are present to allow fine control of the slope linearity. The magnet current is measured and analyzed. Errors are corrected by adjusting the charging voltages and the switch timing. The precision of the waveform is maintained even if circuit parameters change slightly due to aging or component tolerances.

As part of a collaboration with the SSC, CEA/Saclay has designed superconducting quadrupole magnet for the High Energy Booster ring. A number of prototypes are being built at Saclay, after which the production will be handed over to an American firm. This paper presents the mechanical, thermal and electromagnetic analyses which have been performed during the design of the magnet. >

Space-charge effects have been identified as the most serious intensity limitation in the CERN PS and PS Booster, on the way towards ultimate LHC performance and beyond. We here explore the application of several previously proposed space-charge compensation methods to the two LHC pre-injector rings, and the challenges which need to be overcome. The methods considered include the reduction of tune shift and resonance strengths via octupoles, pole-face windings, electron lenses, or neutralisation.

An increase of beam intensity and brightness is essential for future upgrades of existing CERN proton accelerator facilities. A first step can be an injection of H− ions from a new higher energy H− linear accelerator called Linac4 into the Proton Synchrotron Booster (PSB). A second step could be the complete replacement of the PSB by a high‐power linear accelerator, called SPL, injecting directly into the Proton Synchrotron (PS). Both injection scenarios require a high performance, high reliability negative hydrogen ion source. This paper will present the challenging source requirements and the two approaches to fulfill them.

Turn-by-turn data from a single BPM includes information on the chromaticity in sidebands displaced above and below the betatron frequency by an amount of the synchrotron frequency. It may be necessary to induce small amplitude synchrotron oscillation by giving the beam a small kick. Power spectrum of the BPM data gives clear chromatic sidebands, and they can be applied to the chromaticity measurement in the Fermilab Booster.

The difference between the effective rf voltage and the accelerating voltage required to match the rate of change of the Booster magnetic field can be used to estimate the energy loss per beam turn. Although the effective rf voltage (RFSUM) and the synchronous phase can be experimentally measured and used to calculate the accelerating voltage, the calibration of the signals during the fast change of the Booster rf frequency is difficult and appears to introduce some offset to the beam energy loss estimation. An observed linear relationship between energy loss and beam intensity is used to evaluate the offset, which is then applied to the experimental data. This approach, rather than recalibrating the signals, is simple and suitable for minimizing the error in the data.

The space charge limit in circular program accelerators has been studied using a simulation program. Results from the simulation study indicate a different model for the space charge limit than the often-presented models which emphasize resonances due to magnetic field errors. In studies of three operating accelerators, which include the Alternating Gradient Synchrotron, the Proton Synchrotron Booster, and the Fermilab Booster, it was found that the computed intrinsic space charge limit was fairly close to the experimentally observed space charge limit. This result and studies of the effects of resonances due to magnetic field errors suggest that the intrinsic space charge limit provides an upper bound for the space charge limit which is not far from what is actually achieved by operating accelerators. The resonances present due to magnetic field errors, if strong enough, can prevent the accelerator from achieving the intrinsic space charge limit. However, the effects of these resonances were found to be appreciable only when the beam intensity gets close to the intrinsic space charge limit. Well below the intrinsic space charge limit, there is little beam growth due to magnetic field error driven resonances, and the space charge forces tend to stabilize these resonances. >

Beam performance results for the injection phase of proton beam commissioning of the Alternating Gradient Synchrotron (AGS) booster synchrotron are presented. The beam from the 200 MeV LINAC is transported through a new beam line into the booster. This LINAC-to-booster (LTB) beam line includes a 126 degrees bend and brings the injected beam onto the Booster injection orbit through the backleg of a main-ring dipole magnet. Transfer of the beam from the LINAC to the booster, the spiralling beam, and closing of the orbit in the booster ring are discussed. Injection and transport through one sector of the ring were accomplished. >

The delivery of a beam with characteristics appropriate to the filling of the LHC (Large Hadron Collider) proton-proton collider requires that the CERN PS complex provide a beam whose transverse particle density exceeds, by a factor of three, the highest currently attained. The beam dynamics operations and the associated hardware modifications which would be required to achieve this goal are considered. The approach favored involves filling the Proton Synchrotron (PS) with two pulses from the Proton Synchrotron Booster (PSB) and requires and RF quadrupole (RFQ2) as a preinjector for the linac (LINAC2), an increase of the PSB extraction energy and additional RF systems, both in the PSB and PS. >

The KAON Factory will require over 2000 magnets to transport protons from the existing 500-MeV cyclotron through three storage rings and two synchrotrons and deliver them to the experiment area at 30 GeV. The magnet requirements are summarized and the results of measurements on prototypes for the 50-Hz booster magnets are compared with design values. The results of prototype work, some of the more difficult design aspects of other magnets, and the tolerances required to achieve production magnets uniform to +or-2 parts in 10/sup 4/ are discussed. >

The design concepts for ferrite-tuned accelerating cavities discussed differ from conventional solutions using thick ferrite toroids for frequency tuning. Instead, tuners consisting of an array of ferrite-loaded striplines are investigated. These promise more efficient cooling and higher operational reliability. Possible improvements in both voltage holding and average power handling are examined. A variety of options discussed permit substantial improvements on both voltage holding capabilities and tolerable RF power levels of ferrite-tuned cavities for rapid-cycling booster synchrotrons. Layout examples for the SSC-LEB RF system are presented (tuning range 47.5 to 59.6 MHz, repetition frequency 10 Hz). >

The fast-growing "Ring 4" instability occurring at intensities above 6.5/spl times/10/sup 12/ protons in the top one of the four rings of the CERN PS Booster (PSB) is finally explained by an asymmetry in the 40 vacuum pump manifolds common to all rings. Measurements (by wire method) and calculations show a sharp resonant peak (Q/spl sim/2000) at 1100 MHz and shunt impedances two times higher for the Ring 4 ports as compared to the other rings. This factor is sufficient to explain that the threshold of the instability falls below the maximum intensity only in Ring 4. A final, but labor-intensive and expensive, cure consists of inserting short-circuiting sleeves into all 160 beam ports. Results of beam and impedance measurements and the planned cure will be presented and discussed.

A beam-abort dump for the Fermilab Main Injector to handle 3E13 protons per pulse at 150 GeV has been designed. A 120 GeV beam line goes through the beam-dump off-set by 27 cm from its center. The design and the environmental safety aspects of the beam-dump are described here.

Recently, it was proposed to use negatively charged electron beams for compensation of beam-beam effects due to protons in the Tevatron collider. The authors show that a similar compensation is possible in space-charge dominated low energy proton beams. The idea has a potential of several-fold increase of the FNAL Booster beam brightness. Best results will be obtained using three electron lenses around the machine circumference, using co-moving electron beam with time structure and profile approximately matched to the proton beam. This technique, if feasible, will be more cost effective than the straightforward alternative of increasing the energy of the injection linac.

Since the move of ISOLDE from CERN’s synchrocyclotron (SC) to the Proton Synchrotron Booster (PSB) in 1992 extensive work has been devoted to the development of new beams, i.e. the production of new isotopes, beams of higher intensity and the ionization of further elements. Most of these developments were driven by the particular needs of the physics community proposing new experiments. The main achievements were the adaption of liquid metal targets to the pulsed proton beam to prevent shockwaves and splashing inside the target container and systematic studies on the time structure of the release of the isotopes from the target. Furthermore the work on laser ion-sources already started at ISOLDE-2 was continued, the so-called RIST target was developed, and most recently first tests on the isotope production while increasing the proton energy from 1 GeV to 1.4 GeV were done. The latter topics are discussed in this paper.

This paper reviews 40 years of operation of the CERN Proton Synchrotron Booster, from the commissioning in the early 1970s until today's operation as injector for the Large Hadron Collider (LHC) and as one of the backbone accelerators for CERN's fixed-target physics program.

The design goal for the Fermilab Main Injector (FMI) is to accelerate a minimum of 6/spl times/10/sup 10/ protons per bunch through the transition. We present here the results from simulation studies of the transition crossing in the FMI using the particle tracking code ESME.

A study of Intrabeam Scattering (IBS) in the High Energy Booster (HEB) is presented. Piwinski`s formulas for IBS are presented and evaluated for the HEB. A computer code written to evaluate Piwinski`s formulas is discussed. The result of the study is that IBS should not be a problem for the HEB, although the safety factor is not enormous.

The many varied types of spool pieces for the High Energy Booster (HEB) of the Superconducting Super Collider (SSC) Laboratory are presented. Each type of spool piece is discussed, and the specific components are identified. The spool piece components allow each spool piece to perform as a unique electromechanical device positioned in series with large superconducting magnets to provide electrical and mechanical support for each superconducting magnet in areas of cryogenics, electrical power, instrumentation, diagnostics, and vacuum. A specialized HEB superspool is identified that perhaps has the potential to aid in the overall configuration management of the HEB lattice by combining HEB superconducting quadrupole magnets and spool pieces within a common cryostat.

The detailed studies of aperture limitations, beam loss scenarios and energy deposition calculations have been performed to establish the requirements on a collimation system for the High Energy Booster (HEB), 2 TeV superconducting injector for the Supercollider. Calculations of a source term and hadronic and electromagnetic cascades in the HEB components and shielding are done with MARS12 code, particle tracking trough the lattice-with STRUCT code. A multicomponent beam collimation system is proposed to provide reliable operation of the HEB under any circumstances and a clean 2 TeV beam injected into the Collider.

A superconducting model dipole magnet has been designed to serve as a vehicle in an R&D program to develop a dipole magnet for potential use in the SSC High Energy Booster. The objective has been to use the Brookhaven National Laboratory (BNL) and Fermi National Accelerator Laboratory (FNAL) 50 mm aperture dipole designs to the maximum possible extent for design of a dipole magnet with the same size aperture and a field intensity of 6.67 T. Objectives of this program have also included an evaluation of magnet cross section designs which provides increased margin and includes a field quality iteration on BNL and FNAL dipole designs. The salient parameters of this magnet are listed in Table 1. In this paper the 2D magnetic and mechanical design of the cold mass in conceptual and detail form is presented.

Beam-Loss Monitors (BLM) are used with each accelerator in the Superconducting Super Collider complex. The primary purpose of these detectors is to protect the accelerators from damage due to the loss of protons. Although the range of primary beam energies to be covered is very large, 20 MeV to 20 TeV, we plan to maintain commonality of detectors and electronics as much as possible. In this report the plans for developing and implementing BLM systems for each of the accelerators will be discussed. Possible solutions to problems that have been identified are presented.

The history of the project will be traced from 1982 to present. The factors influencing the choice of site will be mentioned. Comparison with other accelerators will be made. Other topics covered are status of civil construction, design of magnets for the 4 injector accelerators, status of RF accelerating systems and status of particle detectors. The final topic will be projected plans and schedules. The detailed status of superconducting magnets and cryogenic plants will be covered by other talks in this session.

This paper presents the preliminary mechanical finite element analysis for the SSCL designed DSB dipole magnet. This SSCL version 50 mm aperture dipole magnet is for the SSCL High Energy Booster with nineteen turns, three wedges for inner coil and twenty six turns, one wedge for outer coil, the round collar is nineteen mm thick, the yoke and the shell are adopted from the design for quadrupole QSE101.

Analytical estimation of the transverse emittance growth due to a point-like perturbation is performed for a proton synchrotron machine. This emittance growth is caused by the tune spread within the bunch. However, the emittance growth suffers a saturation effect caused by the same tune spread. Computer simulations on the emittance growth due to resistive wall instabilities and feedback systems verify qualitatively this emittance growth saturation effect. These simulations were accomplished in the Medium Energy Booster of the Superconducting Super Collider using the TADIMMI computer code.

Eddy currents are developed in the tuner of the Superconducting Super Collider Low Energy Booster (LEB) cavity during the LEB frequency sweep. The two main difficulties created by the eddy currents are excessive tuner‐surface heating, and more important, a reduction in the time response of the tuner. We present a detailed analysis of the eddy currents for various tuner designs. The analysis has been done using 2D and 3D time‐domain finite element codes (PE2D by Vector‐Field and EMAS by MSC). Non‐linear analysis was performed utilizing B‐H curves. The codes have been benchmarked analytically and by using measured data for different slotted pillbox structures.

Progress in the use of one‐turn maps for long‐term tracking of particles—useful in dynamic aperture studies on large circular accelerators—is reviewed briefly. It is recommended that long‐term tracking of particles for large circular accelerators such as the Superconducting Super Collider (SSC) or its high‐energy booster be performed with one‐turn maps. The advantages are twofold: not only is tracking speed dramatically enhanced (by about two orders of magnitude for the SSC), but one‐turn‐map tracking also offers an easier reliability check of the tracking results and easier order‐by‐order analysis.

The presentation on ion profile monitors using microchannel plates consists of two principal parts. The first part describes the design and performance of a profile monitor that was installed in the Debuncher Ring of the Antiproton Source at Fermilab. The information presented relies to a large extent on the contents of a previously published article describing that project [1]. The second part of the presentation describes work in progress on a turn‐by‐turn profile monitor for the Fermilab Booster. A written description of that work is included elsewhere in these proceedings [2].

Future CERN programs for the large hadron collider (LHC) and the isotope online separator (ISOLDE) require increasing the beam intensity and brightness from the proton synchrotron booster (PSB). This could be achieved by charge-exchange injection with phase-space painting into the PSB acceptance from a higher energy H− linac. A new injector will require a high performance, high reliability, negative hydrogen-ion source. This article will present the results achieved so far with a prototype microwave-driven source operated with three different magnetic structures (multicusp, solenoidal, and a combination of both). The experiments were carried out with different mixing gases, different chamber inserts, and under a wide range of operational conditions.

Charged particle beams in circular accelerators often become unstable and execute coherent transverse oscillations that grow in amplitude. These are driven by deflecting fields set up by currents induced in the vacuum chamber walls or other equipment by the oscillating beam itself. This unwanted interaction between the beam and its surroundings is characterized by a transverse coupling impedance Z T . We show that it is relatively easy to measure Z T for accelerator components with large impedance such as kicker magnets, and that useful results can also be obtained for components with small impedance, such as vacuum chambers, although in this case one is close to the limits of accuracy with ordinary laboratory equipment.

A data acquisition and control philosophy for the Zero Gradient Synchrotron (ZGS) 500 MeV booster has involved a top down design incorporating all of the systems comprising the booster. Consideration of operational complexity was necessary because the booster is to be used simultaneously for ZGS injection, and solid state physics studies. Existing software and hardware capabilities of the ZGS computer were considered.1 The resulting data acquisition and control system is based on a mix of sequential logic and a minicomputer. Hardware considerations were based on a ten year life expectancy of the booster. Due to time, budget, and manpower constraints, the incorporation of the total design has been divided into three phases of implementation. The first phase will be covered in this paper and the remaining phases will be outlined.

For filling the Antiproton Accumulator ring, the beam in the PS must be concentrated within one quarter of its circumference. A first step is to inject as much beam as possible into two groups of five PS buckets each occupying one quarter of its periphery. For this purpose, beams from the 4-ring injector synchrotron (PSB) are recombined in pairs by means of an RF dipole magnet which permits longitudinal interleaving of successive bunches. Each PSB bunch being slightly under 180° in length, two of them can fit into a (stationary) PS bucket. It is shown that the use of a sinusoidal deflecting field instead of the ideal square wave results in only a modest growth of the transverse emittance of the recombined beams. The increase of longitudinal emittance by a factor of ~ 3, inherent to the scheme is also acceptable for the PS machine. We discuss the beam dynamics aspects, the construction of the 8 MHz, 250 gauss meter deflecting magnet and the experimental results.

The construction and operation of the system to transfer the 500 MeV proton beam from the fast cycling booster synchrotron to the main ring are described. The observations of beam properties in the transfer process show that the emittances of the beam extracted from the booster are properly transformed to the acceptances of the main ring. The transfer efficiency is measured to be close to 100 %.

Analytical expressions are derived in order to compute the optimum injection parameters for betatron stacking into a chosen fraction of the total accelerator acceptance in the Q range N + 0.1 ? Q ? N + 0.9. The example of the CERN PS Booster (PSB) is worked out. The efficiency of the process is calculated using standard numerical integration algorithms with a Gaussian distribution of the incoming beam. Other types of distribution can also be dealt with. The results show that the installation of pulsed dipole and quadrupole supplies to obtain steering and focusing conditions which vary during the injection process will improve the injected current by only 3% in the case of the PSB. The measured performance of the PSB injection system is reported and compared with model prediction. Estimates of injected currents prove to be about 10% higher than the actual values. Some considerations on the influence of space-charge forces, which might explain this effect are presented.

The main features of this 800 MeV injector are described. The design philosophy is discussed.

For efficient antiproton production, a maximum number of protons must be concentrated within one quarter of the CERN Proton Synchrotron (PS) ring before sending the beam to the production target. With the Antiproton Collector (AC) added to the Antiproton Accumulator (AA), the bunch length has to be shorter (by about 20 ns) than before to allow bunch rotation in the AC. While a more ambitious scheme providing such a beam is being implemented, a funneling method, in which beams of two rings of the four-ring Proton Synchrotron Booster (PSB) are recombined in pairs by an RF dipole that permits longitudinal interleaving of successive bunches, has been in operation since the start-up of the AC. Preliminary experiments had shown that the PS space-charge limit had to be overcome in order to make the scheme feasible. After raising the PSB output energy from 815 MeV to 1 GeV, beams of >10/sup 13/ protons compressed into one quarter of the PS ring were achieved. Related to this development, a record proton beam for fixed-target physics was accelerated in the Super Proton Synchrotron, while beam losses in the Proton Synchrotron Booster-Proton Synchrotron Ring (PSB-PS) line were reduced. >