GSI, Darmstadt
Scintillation screens are widely used for qualitative beam profile monitoring, but precise profile measurements yields ambivalent results for high beam currents. Moreover, these screens are an essential part of a pepper-pot emittance system requiring a quantitative profile evaluation. Therefore, we investigated the optical properties of 14 scintillating materials with different beams in the energy range 5.5 to 11.4 MeV/u as delivered by the heavy ion linac at GSI. Beside sensitive scintillators like YAG we focus on ceramic materials with lower light yield, like BN, ZrO2, Al2O3 and Al2O3+Cr. Their properties (light yield, beam width, high statistical moments etc.) are compared to different quartz glasses. The image of each macro-pulse is recorded by a digital CCD camera and individually evaluated by a high performance data acquisition system. For some materials, a decay of the light yield and an increase of the imaged beam width were observed. Moreover, the light yield depends on the screen temperature, which is significantly increased by the beam impact. A quantitative comparison under different beam conditions is presented.
GSI, Darmstadt
HIT, Heidelberg
The Heidelberg Ion Therapy Center (HIT) for tumor treatment is presently being commissioned using the beam diagnostic devices designed and produced by the GSI beam diagnostic department. To fulfil the requirements for hadron therapy a high-resolution analysis of the particle distribution within the slowly extracted beam is necessary. We present spill-structure measurements for carbon ion beams at energies from 88 MeV up to 430 MeV, also with respect to the spill-pause and abort functionality of the rf-knock-out extraction method. The spill-structure, as measured by internal intercepting ionization chambers (IC) is compared to data recorded with external beam loss monitors (BLM). The high-resolution data acquisition system with sampling rates up to 10 kSa/s and the connected detectors are described and the achievements during the commissioning phase are discussed.
LBNL, Berkeley, California
The superconducting, electron cyclotron resonance (ECR) ion source VENUS has been designed for the dual roles of ion injector for the 88-Inch Cyclotron at LBNL and prototype high current, medium charge state injector for the driver linac of a proposed U.S. radioactive ion beam facility. Ion beam extraction and transport from an ECR is complicated as the plasma-confining solenoidal and sextupolar fields produce beams lacking axial symmetry, these beams are composed of multiple charge states with varied distributions at extraction, and the beams undergo species-dependent rotation while leaving the confining magnetic fields. We are developing an accurate, adaptable simulation model to aid in both understanding the current VENUS system and optimizing the source and transport system for the future facility. VENUS has been outfitted with various beam diagnostics such as viewing screens, a multi-wire harp, emittance scanners, and energy analyzers, and these play an essential role in correlating simulation with experiment. We will describe in detail the diagnostics employed in the VENUS beam line. Measurements with these devices will be presented and compared with ion beam simulations.
GSI, Darmstadt
LBNL, Berkeley, California
TU Darmstadt, Darmstadt
Non-intercepting Beam Induced Fluorescence (BIF) monitors determine transversal beam profiles by observation of fluorescence light originating from excited residual gas molecules. Thus they are an alternative to conventional intercepting devices. Single photon counting is performed using an image intensified digital CCD camera. We investigated the BIF process in the energy range of 7.7 keV/u to 750 MeV/u in residual nitrogen. Experiments at low beam energies were performed at a Marx-accelerator (NDCX) at Berkeley Lab whereas mid and high energy experiments were carried out at GSI accelerators. Especially in the vicinity of targets the neutron-generated radiation level limits the monitor's signal to background ratio. Therefore the radiation background was investigated for different ion species and particle energies. Background simulations using a Monte Carlo transport code are compared to experimental data measured with scintillators, thermo luminescence detectors and the BIF monitor. Alternative image intensifier techniques are presented as well as shielding concepts. Furthermore the dynamics of ionized nitrogen molecules in the electric field of intense ion beams is discussed.
CEA, Gif-sur-Yvette
In the IFMIF-EVEDA framework, a high deuteron beam intensity (125 mA - 9 MeV) accelerator will be built and tested at Rokkasho (Japan). The development of this accelerator is shared between France, Italy and Spain. France (CEA-Saclay) and Spain (Ciemat-Madrid) are responsible of the beam instrumentation from the RFQ to the beam dump. One of the most challenging detectors is the Beam Transverse Profile Monitor (BTPM), and the Saclay group decided to investigate such a monitor based on residual gas ionisation. In order to study the feasibility, we plan in a first step to built a prototype. This monitor use a high electric field to drive the products (electrons and ions) of ionisation to resistive micro-strips. At first sight, no amplification is necessary! This prototype will be tested in the IPHI high intensity (100 mA) proton beam at Saclay to answer this question in particular, and to check the feasibility in general.
Fermilab, Batavia
This paper presents a condensed, simplified, and practical discussion of the principles, procedures, and operating parameters of particle accelerator vacuum systems as practiced at Fermilab. It is intended to provide a basis for designers, builders, and operators of accelerator systems to communicate with each other about the needs and impact of the vacuum system. Rigorous analytical development of the equations and concepts are not given. It is assumed that the reader has some limited understanding of the subject. Practical examples of real world experiences are used to illustrate the concepts outlined.
KIP, Heidelberg
GSI, Darmstadt
The development of new particle accelerators with unprecedented beam characteristics has always driven the need for an intense R&D program in diagnostic techniques. The successful operation of these machines is finally only possible with an adequate set of beam instrumentation. DITANET is a large European network between several research centres, Universities, and partners from industry that aims for the development of beyond-state-of-the-art diagnostic techniques for future accelerator facilities. This includes research projects focusing on beam profile, current, and position measurements, as well as on particle detection techniques and related electronics. A particular focus of the consortium is the training of young researchers in this multi-disciplinary field and to thus prepare them for their future careers in academia or industry. This contribution will introduce the network participants, present the general structure of DITANET, and give an overview of its research and training activities.