MV Tandem Electrostatic Accelerator Research Articles

Detection and analysis of laser driven proton beams by calibrated Gafchromic HD-V2 and MD-V3 radiochromic films.

The radiochromic film (RCF) is a high-dose, high-dynamic range dosimetry detection medium. A stack of RCFs can be used to detect both spatial and energetic distribution of laser driven ion beams with a large divergence angle and continuous energy spectrum. Two types of RCFs (HD-V2 and MD-V3, from Radiation Products Design, Inc.) have been calibrated using MeV energy protons and carbon ions produced by using a 2 × 6 MV tandem electrostatic accelerator. The proportional relationship is obtained between the optical density and the irradiation dose. For protons, the responses are consistent at all energies with a variation of about 15%. For carbon ions, the responses are energy related, which should be noted for heavy ion detection. Based on the calibration, the broad energy spectrum and charge distribution of laser accelerated proton beam with energy from 3 to 8 MeV and pC charge were detected and reconstructed at the Compact LAser Plasma Accelerator at Peking University.

Performance and application of heavy ion nuclear microbeam facility at the Nuclear Physics Institute in Řež, Czech Republic

The Tandetron Laboratory of the Nuclear Physics Institute of the Czech Academy of Sciences is equipped with five beam lines associated with a 3 MV tandem electrostatic accelerator model 4130 MC from High Voltage Engineering Europa B.V. This accelerator is coupled with two duoplasmatron sources and a single sputter ion source and provides ions from hydrogen to gold. One of these lines is a nuclear microbeam facility, utilizing ion beams of micro- and sub-micro sizes for materials research by use of particle induced x-ray emission spectroscopy, particle induced gamma emission, Rutherford back-scattering spectroscopy, and scanning transmission ion microscopy methods as well as for ion beam writing. The major advantage of the presented microprobe is a possibility of 3D structure creation not only in polymer materials using light ions but also in other materials such as glass, ceramics, etc. by use of heavy ions. The focusing system allows focusing of charged particles with a maximum rigidity of 11 MeV amu/q2. The usual resolution in high and low current modes is 2 × 3 µm2 for a 100 pA and 0.3 × 0.5 µm2 for the 2000 ions/s of 2 MeV protons, respectively. A detailed facility description is given in the paper. The applications of focused beams of heavy ions as well as examples of light ions utilizing are also presented in the article.

The 6 MV Tandem Electrostatic Accelerator for Multipurpose Ion Beam Applications at the University of Tsukuba

The 6 MV Tandem Electrostatic Accelerator for Multipurpose Ion Beam Applications at the University of Tsukuba

Mubeam system for study of single event upset of semiconductor devices

A high energy heavy ion mubeam system has just been installed on a beam line of the 3 MV tandem electrostatic accelerator mainly for analysis of single event upset (SEU) of LSI memories in spacecraft. This system was designed for precise beam positioning at a desired muscopic area of the mucircuit, to experimentally evaluate of actual SEU sensitive area, and also to allow single ion hits for observing a transient charge pulse from an SEU. For these purposes, a fair amount of target beam current is required for beam positioning at the desired area. The system is equipped with two lens systems: one to control the target beam current in a wide range down to an extremely low current without any change of the beam optics, and the other to focus heavy ion beams within a spot size of 1 μm. The final goal is to hit a muscopic target area with a single 15 MeV nickel ion.

Status of the positive ion injector for atlas

The positive ion injector project will replace a High Voltage Engineering Corp. model FN 9 MV tandem electrostatic accelerator as the injector into the ATLAS superconducting heavy ion linear accelerator. It consists of an electron cyclotron resonance (ECR) ion source on a 350-kV platform injecting into a linac of individually phased superconducting resonators which have been optimized for ions with velocities as low as β = 0.009. The resulting combination will extend the useful mass range of ATLAS to projectiles as heavy as uranium, while increasing the beam currents available by a factor of 100.

The ORNL 25 MV tandem accelerator control system

The CAMAC-based control system for the 25 MV tandem electrostatic accelerator of the Holifield Heavy Ion Research Facility at Oak Ridge National Laboratory (ORNL) was specified by ORNL and built by the National Electrostatics Corporation. Two Perkin-Elmer 32-bit minicomputers are used in the system: a message switching computer and a supervisory computer. The message switching computer transmits and receives control information on six serial highways. This computer shares memory with the supervisory computer. Operator consoles are located on a serial highway; control is by means of a console CRT, trackball, and assignable shaft encoders and meters. Two identical consoles operate simultaneously: one is located in the tandem control room; the other is located in the cyclotron control room to facilitate operation during injection of tandem beams into the cyclotron or when beam lines under control of the cyclotron control system are used. The supervisory computer is used for accelerator parameter setup calculations, actual accelerator setup for new beams based on scaled, recorded parameters from previously run beams, and various other functions. The experience of nearly seven years of control system operation and improvements is discussed.

The Present Status of the Daresbury Nuclear Structure Facility

The Daresbury Laboratory of the Science Research Council is constructing a 30 MV tandem electrostatic accelerator. The R & D programme supporting the design of the accelerator is outlined, and the present state of the project is described.

Magnetic Field Measuring System for Remapping the ORIC Magnetic Field

The Holifield Heavy Ion Research Facility will integrate a new 25 MV tandem electrostatic accelerator into the existing cyclotron laboratory which includes the Oak Ridge Isochronous Cyclotron (ORIC). 1 Computations of ion paths for beam injection from the new tandem into ORIC require field mapping in the regions traversed by the beam. Additional field data is also desired for the higher levels (~19 kG) now used for most heavy ion beams. The magnetic field measurement system uses 39 flip coil/current integrator sets with computer controlled data scanning. The coils are spaced radially at 1 inch intervals in an arm which can be rotated azimuthally in 2 degree increments. The entire flip coil assembly can be shifted to larger radii to measure fields beyond the pole boundary. Temperature stabilization of electronic circuitry permits a measurement resolution of ±1 gauss over a dynamic range of ±25,000 gauss. The system will process a scan of 8000 points in about one hour.

Design Status of a Separated-Sector Cyclotron Booster Accelerator for the Holifield Heavy Ion Research Facility

A separated-sector cyclotron booster accelerator is being designed for the Holifield Heavy Ion Research Facility as a Phase II project to be started in 1978. Phase I of the HHIRF, now under construction, includes a 25 MV tandem electrostatic accelerator, a beam transport and injection system to enable use of the Oak Ridge Isochronous Cyclotron as an energy booster for tandem beams, and some additional experiment areas and associated beam transport systems. The Phase I facility using the ORIC-25 MV tandem combination will provide energies up to about 25 MeV/amu for light ions such as oxygen and more than 5 MeV/amu up to the region of mass 160. The new Phase II separated-sector cyclotron will provide energies up to 100 MeV/amu for light ions and up to 12 MeV/amu for the heaviest ions such as uranium.

ORIC RF System - Preparation for HHIRF

The integration of the Oak Ridge Isochronous Cyclotron (ORIC) into the Holifield Heavy Ion Research Facility (HHIRF) requires several RF system modifications to permit injection of ion beams from the 25 MV tandem electrostatic accelerator into ORIC. A new dee eliminates structural interference with the injected beam path and provides an opportunity to improve the mechanical stability of the resonator and to reduce RF voltage gradients in areas susceptible to sparking. Space for structural improvements is realized by reducing the ion beam aperture from 4.8 cm to 2.4 cm. The complexity of the original ORIC RF power system has been substantially reduced. A new broadband solid state driver amplifier between the frequency synthesizer and the main power amplifier eliminates most circuit tuning and permits the use of a new simplified dee RF voltage regulator loop. Most of the remaining instrumentation and control circuitry is TTL compatible and will eventually tie to the ORIC computer control system through a CAMAC interface.

Calculated Finite Emittance and Dee-Gap Crossing Effects on Heavy-Ion Trajectories of ion Injection into the Oak Ridge Isochronous Cyclotron from a 25 Mv Tandem Electrostatic Accelerator

The present calculational results are part of a continuing study to assist in optimizing the geometry and flexibility of the ORIC injection system. The calculated effects of finite emittance and dee-gap crossings during ion injection on beam size and quality at the stripper foil are presented.

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.