Heavy Ion Facility Research Articles

Implications of heavy-ion-induced satellite X-ray emission III: Chemical effects in high-resolution sulfur K α X-ray spectra

High-resolution ( ∼ 7 eV at 2.3 keV) sulfur K α X-ray spectra have been obtained for a series of sulfur compound targets under heavy-ion impact at the Holifield Heavy Ion Facility. The spectra observed are dominated by a series of satellite peaks arising from varying degrees of L-shell ionization at the time of X-ray emission. Each spectral profile has been parameterized by a single variable p L, the apparent average L-shell ionization probability. Correlations are evident between p L and the corresponding sulfur atom chemical environment. Much stronger correlations are, however, found for variations of some individual peak intensities with specific chemical parameters. Comparison of results for Ar q+ and Kr q+ projectiles show that while L-shell ionization probability has increased, chemical sensitivity has apparently saturated.

Progress report on the Laboratorio Nazionale Del Sud (LNS) at Catania

The LNS heavy ion facility under construction in Catania consists of an SMP tandem Van de Graaff that will be coupled to a superconducting cyclotron with K = 800. The installation of the tandem was completed in November 1982 and acceptance tests are under way. At the moment a maximum voltage of 13.7 MV has been reached with a proton beam transmission better than 85%. A review of the state of the various parts of the project is given in this paper.

The lund monte carlo for e +e − jet physics

The lund monte carlo for e +e − jet physics

The sector magnet for the IPCR SSC

The accelerator complex of heavy ion facility projected at the Institute of Physical and Chemical Research (IPCR) consists of a separated-sector cyclotron (SSC), a variable frequency linac[1] and a conventional AVF cyclotron. The main magnet system of this SSC consists of four sector magnets with a sector angle of 50 degrees, gap distance of 80 mm and weight of 530 tons per a sector. The design parameters of the sector magnet were determined from the measurements of the magnetic properties of two 1/4-scale sector magnets. The final design of the sector magnet was completed. The magnet design has been based on the model measurements and the technical problems of the construction are presented. The first sector magnet has been placed an order at the beginning of 1981.

SIS - A Two Stage Synchrotron Facility for Heavy Ions

The GSI studies for a new large 14 GeV/u heavy ion facility have been continued. Once again concepts for two-stage facilities have been studied that combine a fast cycling booster synchrotron with a slowly cycling high energy synchrotron. In the proposed facility the total power consumption will be moderate, when superconducting magnets are used in the high energy synchrotron, and the operational versatility will allow experiments with free choice of ion species and energy in both energy ranges, 20 to 1000 MeV/u as well as 1 to 14 GeV/u. With respect to the two-stage concept the design of a new high current linear accelerator has been optimized.

A Proposed Design for a Fast (Parallel) Preprocessor for the Spin Spectrometer and Other Eventful Albatrosses

Because devices like the Spin Spectrometer described in a previous paper to this conference can produce an extremely fast but fairly simple-to-process data stream, it seems reasonable to consider front-end preprocessors having special characteristics. In general, the kinds of transformations being considered do not require floating point calculations or extensive calculations. In order to be somewhat specific, the particular data acquisition/processing problems posed by the Spin Spectrometer at the Holifield Heavy Ion Facility will be discussed.

A large superconducting dipole magnet for the heavy ion spectrometer system (HISS)

The magnet is the central element of the spectrometer system, where it will be used to momentum-analyze secondary heavy-ion fragments at relativistic energies. High bending power and large acceptance apertures are necessary for simultaneous multiple fragment measurements. Free access over large angles to the magnetic volume is necessary to accommodate a variety of experiments and particle detection systems. The magnet has pole tips two meters in diameter, a one meter gap, and a maximum central field of three tesla. The coils are designed to be cryostable, with a helical winding pattern. A window-frame steel yoke limits the stray field and augments the central field. In terms of its magnetic energy of 55 MJ it will be one of the twelve or so largest magnets in the world. Unusual engineering features of the magnet are the large magnetic forces (one million kg) between the coils at liquid helium temperature and the yoke at room temperature, and the large diameter (7 m) hydraulic cylinder base to provide rotation for the magnet. The magnet will be installed at the BEVALAC heavy-ion facility at Lawrence Berkeley Laboratory.

Making targets for a new heavy ion facility

The superconducting linac now being built and tested at the Argonne National Laboratory and to be used with the FN Tandem has as its objective to provide precision beams of heavy ions for physics research. Providing stripper foils having reasonable lifetimes for the linac as well as for the Tandem when using heavy ions is a necessity. We have shown that either heating or rotating the foils or a combination of both increases their lifetime. We now find that the lifetime can be significantly increased by high speed rotation of a disc containing the foils. Techniques have also been developed to increase the lifetime of targets used in experiments having intense beams and which may be applicable to heavy ion physics. These techniques involve principles of conductivity, radiation, and target rotation.

Present Status and Further Developments of the VICKSI Heavy Ion Facility

The VICKSI accelerator facility, a combination of a 6 MV Van de Graaff injectorand a split pole cyclotron has been completed. Extensive beam tests and regular operation indicate that all specifications are obtained. Seven differentions have been accelerated to 23 different energies since the running in periods in 1977. In 1978 the beam was actually available about 60% of the time scheduled for experiments. A second injector for the cyclotron is presently under study. It has been approved by the advisory committee to the scientific board and it is planned to be available in 1982.

Some Aspects of Radiation Safety at the Holifield Heavy Ion Facility

A new 25-MV tandem accelerator will be combined with the existing Oak Ridge Isochronous Cyclotron (ORIC). This facility will be capable of providing useful beams of heavy ions with masses up to A = 160 for nuclear physics research. A discussion of past radiation exposure problems at ORIC as well as a projection of exposures that will occur when the new accelerator comes on line are given. The radiation safety system for the new facility is described and a brief safety analysis of the new insulation gas system for the tandem will be given.

The Injection in IPCR Separated Sector Cyclotron

The accelerator complex of the proposed IPCR heavy-ion facility consists of a separated-sector cyclotron (SSC), a variable frequency linac, and an AVF cyclotron. The linac and AVF cyclotron are used independently or serve as injectors for the SSC. The distance from linac to SSC is about 40 m. The beam lines of the accelerators are not in the same horizontal plane. The vertical distance between the two beam lines is about 7 m. The beam transfer system consists of a charge stripper, beam bunchers, conventional bending magnets, and quadrupoles. An apparatus which shifts the phase of beam bunch to much higher harmonic acceleration can be used for high intensity mode.

A New Generation of Heavy Ion Facilities

One area that was not touched on here that is highly relevant to energy boosting of tandem accelerators is that of super-conducting linacs. Although there are not yet major facility proposals based on this technique, a number of laboratories are actively pursuing development studies. A review paper appears in these preceedings as well as several contributions in the session on linear accelerators. Also not discussed was the Bevalac improvement which should provide beams in the upper portion of the region shown in Fig. 1 but with two to three orders of magnitude less intensity than the facilities that have been discussed. Even so, this will be an important member of our heavy ion accelerator arsenal for the next decade. I have tried to summarize the major heavy ion facilities that we should look for through the first of the next decade. I want to end by returning briefly to the subject of the super-tandems. There is an interesting esthetic by-product to these large electrostatic machines. For years we have built horizontal accelerators, often in rather non-descript flat buildings - even tunnels and trenches. But for structural reasons the large tandems are vertical machines and now we have the opportunity to build towers - structures that have always captured mans imagination. Certainly we had a lot of discussion about the form of our tower for Oak Ridge. (Fig. 15) One early suggestion of an architectural style most compatible with our existing buildings is shown in Fig. 16.

A Heavy Ion Facility for Radiation Therapy

The accelerator requirements of particle radiation therapy are reviewed and a preliminary design of a heavy ion synchrotron for hospital installation is presented. Beam delivery systems and multi-treatment room arrangements are outlined.

Present and future sources of protons and heavy ions

A brief outline of existing medical heavy-ion facilities is given. The beam specifications for future dedicated medical ion accelerators are discussed. Machines capable of delivering dose rates of approximately 1 krad/min in volumes of a few liters are shown to represent existing technology. A cost and performance analysis shows the synchrotrons to be the most economical source for the heavier ions while conventional cyclotrons seem optimal for an exclusive proton facility. It is seen that the incorporation of additional capabilities such as neutron generation or radioisotope production can be achieved at modest incremental costs. In addition to the accelerators, feasible layouts of hypothetical facilities are discussed, and three-dimensional beam scanning is shown to allow the irradiation of large volumes without sacrificing the precise dose localization capabilities of heavy-ion beams. Concepts of quality-controlled engineering and modern computer technology are introduced as a means to obtain the desired high degree of reliability and ease of operation and maintenance.

Design Considerations for the ORNL 25 MV Tandem Accelerator

Construction of a 25 MV tandem electrostatic accelerator is now planned as part of a new heavy-ion facility at the Oak Ridge National Laboratory. The design of this accelerator incorporates several unusual features. The most important of these are a folded design, in which the low-energy and high-energy acceleration tubes are contained within a single column structure, and a digital control system. Motivations for these design features are discussed in conjunction with a brief description of the accelerator.