ORNL, Oak Ridge, Tennessee
UMD, College Park, Maryland
The Spallation Neutron Source (SNS) continues a ramp up in proton beam power toward the design goal of 1.4 MW on target. At Megawatt levels, US and Japanese studies have shown that cavitation in the Mercury target could lead to dramatically shortened target lifetime. Therefore, it will be critical to measure and control the proton beam distribution on the target, in a region of extremely high radiation and limited accessibility. Several sources of photons have been considered for imaging the beam on or near the target. These include a freestanding temporary screen, a scintillating coating, Helium gas scintillation, optical transition radiation, and a beam-heated wire mesh. This paper will outline the selection process that led to the current emphasis on coating development. In this harsh environment, the optics design presented significant challenges. The optical system has been constructed and characterized in preparation for installation. Optical test results will be described along with predictions of overall system performance.
Brunel University, Middlesex
Muon ionization cooling provides the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. The muon ionization cooling experiment (MICE) is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A fist measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen and RF acceleration. A second spectrometer identical to the first one and a particle identification system provide a measurement of the outgoing emittance. By April 2009 it is expected that the beam and first set of detectors will have been commissioned, and a first measurement of input beam emittance may be reported. Along with the plan of measurements of emittance and cooling that will follow in the second half of 2009 and in 2010.
GANIL, Caen
LPC, Caen
The SPIRAL2 project is based on a multi-beam driver facility in order to allow both ISOL and low-energy in-flight techniques to produce intense radioactive ion beams (RIB) in a new Facility. A superconducting linac capable of accelerating 5-mA deuterons up to 40 MeV is used to bombard both thick and thin targets. These primary beams will be used for the RIB production by several reaction mechanisms (fusion, fission, etc.) The production of high intensity RIB will be based on fission of uranium target induced by neutrons. These exotic particles will be produced, ionized, selected in a dedicated production building and transported to the existing CIME cyclotron for post acceleration. After this, they will be used in the present experimental area of GANIL. The construction phase of SPIRAL2 was officially started in 2005. The beam diagnostics for the production facility allow a pre-tuning with a stable beam followed by an extrapolation to the radioactive beam. Some diagnostic devices may also provide for equipment protections and for the safety systems. An overview is presented of the diagnostics which will allow tuning and control of the RIB in this new production facility.
INFN/LNF, Frascati (Roma)
Università di Roma II Tor Vergata, Roma
DESY, Hamburg
The characterization of the transverse phase space for high charge density and high energy electron beams is demanding for the successful development of the next generation light sources and linear colliders. Due to its non-invasive and non-intercepting features, Optical Diffraction Radiation (ODR) is considered as one of the most promising candidates to measure the transverse beam size and angular divergence. A thin stainless steel mask has been installed at 45° with respect to the DR target and normally to the beam propagation to reduce the contribution of synchrotron radiation background. In addition, interference between the ODR emitted on the shielding mask in the forward direction and the radiation from the DR target in the backward direction is observed. This is what we call Optical Diffraction Interferometry (ODRI). The contribution of this interference effect to the ODR angular distribution pattern and, consequently, its impact on the beam transverse parameters is discussed. Results of an experiment, based on the detection of the ODRI angular distribution to measure the electron beam transverse parameters and set up at FLASH (DESY, Hamburg) are discussed in this paper.
GANIL, Caen
The SPIRAL2 project is based on a multi-beam driver in order to allow both ISOL and low-energy in-flight techniques to produce Radioactive Ion beams (RIB). A superconducting light/heavy-ion LINAC capable of accelerating 5 mA deuterons up to 40 MeV and 1 mA ions up to 14.5 MeV/u is used to bombard both thick and thin targets. These beams could be used for the production of intense RIB by several reaction mechanisms (fusion, fission, transfer, etc.). In order to visualize the SPIRAL2 beam dynamics, several beam profile monitors are under development. Multiwire beam profile monitors (SEM) will be used on the driver and RIB lines, a non interceptive beam profile monitor (RGM) should be mounted on the LINAC diagnostics box and before the experiment facility, and a low intensity beam profile monitor (EFM) on the RIB lines. Signal acquisition from these monitors will be accomplished through new associated electronics which digitize 94 channels in a parallel system. Each channel integrates the current of the associated wire or strip and performs a current-voltage conversion. The dedicated GANIL data display software has been adapted for these new monitors.
FZJ, Jülich
UniDo/IBS, Dortmund
GSI, Darmstadt
ITEP, Moscow
The advanced ionization beam profile monitor is being developed at GSI for the future FAIR facility in collaboration with ITEP and FZ-Jülich. In January 2009 the IPM prototype was installed in COSY-Jülich. After successful hardware test the beam tests followed. The prototype was operated without magnetic field, thus only residual gas ions were detected. An arrangement consisting of an MCP stack, a phosphor screen, and a CCD camera was used to detect ions. We report the first profile measurements of the proton beam up to 2.8 GeV at COSY.
PSI, Villigen
For the neutron spallation source SINQ at PSI a novel visual monitor (VIMOS) has been devised to guarantee correct beam conditions, triggered at the occasion of irradiating the delicate liquid metal target during the MEGAPIE project. VIMOS is looking directly for the most relevant parameter: it checks whether any point on the target is hotter than allowed. For this purpose the incandescence of a glowing mesh right in front of the beam entrance window is observed by means of dedicated radiation hard optics and suitable cameras. Starting from the initial goal of reliably detecting beam anomalies in a timely manner the scope of the system has been extended to serve as a standard device for beam monitoring and fine tuning of the settings of the proton beam transport lines. Over the course of the five years of continuous reliable operation of this unique system valuable experience has accumulated, which is employed for steady improvements of the device with respect to endurance in the radiation environment, calibration, maintenance, and price. A summary of the operational experience of VIMOS will be reported as well as steps taken towards further upgrades.
CERN, Geneva
A novel radiation hardened current digitizer ASIC is in planning stage, aimed at the acquisition of the current signal from the ionization chambers employed in the Beam Loss Monitoring system in CERN accelerator chain. The purpose is to match and exceed the performances of the existing discrete component design, currently in operation in the Large Hadron Collider (LHC). The specifications include: a dynamic range of nine decades, defaulting to the 1pA-1mA range but adjustable by the user, ability to withstand a total integrated dose of at least 10 kGray in 20 years of operation and user selectable integrating windows, as low as 500ns. Moreover, the integrated circuit can be employed to digitize currents of both polarity with a minimum number of external components and without needing any configuration. The target technology is IBM 130 nm CMOS process. The specifications, the architecture choices and the reasons on which they're based upon are discussed in the paper.
IMP, Lanzhou
HIRFL-CSR, a new heavy ion cooler-storage ring in China IMP, had been installed and started commission from 2005. We report here the BPM system on the main ring (CSRm) and the experimental ring (CSRe). The BPM structure, the signal processing system and on-line measurement experiments are presented. The measurement results such as turn-by-turn bunch observation, closed-orbit measurement, Schottky noise measurement are also presented in this paper.
BNL, Upton, Long Island, New York
We have developed a photodiode-based X-ray beam-position monitor with high-spatial resolution for use on the future beamlines at NSLS-II. A ring array of 32 Si PIN photodiodes were fabricated for a photon sensor, and a newly-designed HERMES4 ASIC die was integrated into the data-acquisition system. A series of precision measurements for electrical characterization of the Si-photodiode sensor and the ASIC die demonstrated that the inherent noise is sufficiently below tolerance levels. Following up with a series of modeling efforts including geometrical optimization, we have built prototype detectors. In this paper, we present the development of the new state-of-the-art X-ray BPM and experimental measurements performed on the existing X12A beamline at NSLS.
NERS-UM, Ann Arbor, Michigan
Michigan Ion Beam Laboratory (MIBL) is equipped with a 1.7 MV tandem particle accelerator and a 400 KV ion implanter. Ion beams can be produced from a variety of ion sources and delivered to different beamlines. Precise beam profiling and current measurements are critical aspects of everyday activity in the laboratory and influence the success of each experiment. The paper will present the beam simulation software employed and the benefits and the shortcomings of the devices used at MIBL to precisely know all the parameters of the ion beams
PSI, Villigen
A new current monitor has been built and installed during the last maintenance period in prevision of the high intensity beam operation (3mA, 1.8MW) which is planned in the near future. It is a re-entrant cavity tuned at the 2nd RF harmonic (101 MHz). Compared to the current monitors already in operation, the design had to be modified to improve its cooling. Indeed, this monitor is placed 8 m behind a graphite target and is exposed to scattered particles. The resulting heat load would raise the monitor temperature well above 200 deg C without cooling. The modifications include a slightly different structure to improve the heat conduction, a blackening of the external surface to increase the thermal radiation and an active water cooling. Thermocouples placed on the cavity will monitor the temperature of the system. The new design was supported by simulations for heat load resulting from the scattered particles and by calculations concerning the cooling efficiency. Results obtained during laboratory tests and at the beginning of operation will be presented. Comparison between expected heat load and temperature with the actual measured values will be also discussed.
CEA, Gif-sur-Yvette
Within the framework of IFMIF-EVEDA project, a high-intensity deuteron beam (125 mA - 9 MeV) prototype accelerator will be built and tested at Rokkasho (Japan) in order to validate the future IFMIF accelerator. One of the most challenging diagnostics is the Beam Transverse Profile Monitor (BTPM), which has to be a non-interceptive device. Two R&D programs have been initiated: one based on residual gas fluorescence developed by Ciemat Madrid (see J. Carmona et al. contribution) and another one based on residual gas ionization developed at CEA Saclay. The principle of the last one is to measure the current induced by the ionization electrons, which drift under an electric field influence, towards several strips to get a one-dimension projection of the transverse beam profile. Preliminary results of a first prototype tested on the IPHI Saclay accelerator will be shown, as well as a new prototype design. In the new design several improvements have been carried out which will be tested soon with continuous and pulsed beam at higher energy.
HIT, Heidelberg
The ion cancer therapy facility HIT in Heidelberg is producing ions (H, He, C and O) from two ECR sources at an energy of 8 keV/u with different beam currents from about 80 μA up to 1.2 mA. Typical sizes for the beam in the LEBT range from are 5 40 mm. Matching the always slightly changing output from the ECR sources to the first accelerating structure, an RFQ, demands a periodical monitoring of the beam emittance. For that, a special pepper-pot measurement device is under design, whose most important parts are a damage-resistant pepper-pot mask and a vacuum-suitable scintillator material. The investigation of the material lifetime is done in the first step by computing the maximum intensity the target volume can stand without any radiation damage, shock and heating. A list of feasible materials will be discussed and results from SRIM calculations for them will be shown. A set-up for necessary material tests with beam will be presented.
CERN, Geneva
Carbon fibres are commonly used as moving targets in Beam Wire Scanners. Because of their thermo mechanical properties they are very resistant to particle beams. Their strength deteriorates with time due to low-cycle thermal fatigue. In case of high intensity beams this process can accelerate and in extreme cases the fibre is damaged during a scan. In this work a model describing the fibre temperature, thermionic emission and sublimation is discussed. Results are compared with fibre damage test performed on the CERN SPS beam in November 2008. For the operation of Wire Scanners with high intensity beams damage threshold are predicted.