A review is given of early development work at the University of Wisconsin on electrostatic accelerators insulated by high pressure gas. This work started in 1933 and led in 1940 to a 4.5MeV accelerator. Starting in 1946 development work was initiated along three lines: 1) Bakeable high strength metal to ceramic bonding, 2) Organic-free pumping, 3) Metal charge carrying devices. In 1951 construction was started at the University of Wisconsin on an accelerator utilizing results of these three development programs. In 1965 much development work was transferred to the National Electrostatics Corp. where the charging chain was developed. It consists of metal cylinders joined by links of solid insulating material. A 1MV column support unit was perfected which is used to construct column modules. A bakeable all metal and ceramic tube, free of organic vapors was developed. It consists of short sections bolted together with three sections per column module. A three-stage accelerator was built and was tested with a beam up to energies of 22MeV. A two-stage accelerator to provide 28MeV protons (14MV on terminal) is under construction. A two-stage accelerator to give 40MeV protons (20MV on terminal) has been designed.

Chain and inductive charging system as a charge-carrying element of the electrostatic generator

The Pelletron Accelerator

I.A - Electrostatic Accelerators

At Kyushu university a 10 MV tandem accelerator is just completed and being tested for the overall performance. The construction of this machine was started five years ago and the design principle has been shown at the electrostatic accelerator conference at Daresbury [1]. This facility cannot be said to be large from the present standard but be called compact. However, radial and axial field gradients of this machine are fairly high at 10 MV so that the design was necessarily made with an intention of overcoming various problems in the conditions of high gradient field. REVUE DE PHYSIQUE APPLIQUÉE TOME 12, OCTOBRE 1977, PAGE 1. Mechanical design feature. Figure 1 shows the mechanical and electrostatic structure of this tandem. The inside diameter of the tank is 3.8 m and the length of each column is 5.3 m. This size is nearly the same as that of the FN tandem. The column is divided into five sections with separating plates and a diagonal insulating post member is placed on center in each section. Arrangement of the horizontal and diagonal posts in the cross section of the column is shown in figure 2. Pellet chains and an accelerator tube are placed at both sides of the diagonal post. This arrangement allows the pellet chains and the tube wide space. The tube is isolated from the column structure and independent dividing resistor chains are used for the column and the tube. The horizontal posts are tightly bolted to the separating plates in each section. In order to enable this sort of construction all the structual components of the column were produced with a very high precision. The length of the diagonal members are made to be adjustable in order to eliminate the bending stress of the horizontal posts. This adjustment was made in every times when the load of the column was added during the construction. The axial compression force by the compression spring was also adjusted as the FIG. 1. Basic mechanical and electrostatic structure of the 10 MV tandem of Kyushu University. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/rphysap:0197700120100131500

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Development of the high-gradient electrostatic accelerator techniques in the Kyushu University tandem

A new type of high voltage generator has been designed, with the aim of developing a compact, inexpensive and easily-maintained generator for energetic ion beam analyses. It has a similar structure to a rotating disk-type generator, such as the Disktron, and has the potential to have a compact size and satisfactory generating voltage stability. Its generating mechanism is, however, rather similar to rectifier type generators, such as the Cockcroft-Walton and the Schenkel types, so that there are no friction components which might produce a lot of dust, so opening the high pressure tank for cleaning is an infrequent operation. The proposed generator can be produced relatively inexpensively. A single module model has been built and it was confirmed that the proposed generating mechanism functions successfully.

Chain and inductive charging system as a charge-carrying element of the electrostatic generator

Citations

The Pelletron Accelerator

I.A - Electrostatic Accelerators

Development of the high-gradient electrostatic accelerator techniques in the Kyushu University tandem

Design of a new high voltage generator for ion beam analysis

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