J. Tanabe

High Energy Beam Transport System for a Heavy Ion Medical Accelerator

A beam transport system for a Heavy Ion Medical Accelerator is presented. The design allows for ease of tuning, similarity of tuning between different beam lines, and future expansion of the number of beamlines. An option for generating secondary beams with acceptable transmission losses to all treatment areas is also included in the design, as is a vertical beamline option for use with patients in a horizontal position.

A Compact Heavy Ion RFQ Preacceleraior for Use at the CERN Linac I

This paper describes the LBL contribution to a project designed to provide fully-stripped oxygen beams for acceleration in the CERN PS complex.[1] A preaccelerator for Linac I, consisting of an ECR ion source, an REQ linac, and RF matching cavities, is being assembled as part of a collaborative arrangement among LBL, GSI, and CERN. The RFQ, designed and built at LBL, will accept analyzed oxygen +6 beam from the ECR at 5.6 keV/amu, and accelerate it to 139.5 keV/amu, the injection energy required for 2 ß¿ operation of Linac I. Stripping to +8 will be done with a foil stripper at 12.5 MeV/amu at the exit of Linac I. The RFQ operates at 202.56 MHz and is 0.86 meters in length. The structure is stabilized with vane coupling rings, and uses a single drive loop and a single tuning loop.

Design of a Three Channel Septum Magnet

A three channel septum magnet has been designed to service the three primary beam lines at the exit of the SuperHILAC. A pulsed switching magnet located in the next to last drift tube in the SuperHILAC poststripper diverts the beam ± 1.09° into either the north or south port of the septum magnet. The central channel allows an undiverted beam to pass into another distribution magnet downstream. All channels may be active simultaneously and each may be tuned independently. Each septum channel contains four separate field regions and bends the beam 14.91°. Various important aspects of the design, including geometry, material selection, thermal characteristics and power requirements, are discussed.

The 50-MeV Bevatron Injection Linac

The BNL 50-MeV injection linac has been installed as a new injector for the Bevatron. The preinjector, linac modifications, and beam transfer lines are described. The linac and modulator have been modified to permit longer pulse operation at a higher peak current. Most support equipment was already on hand and modified for use.

The Bevatron Cryopump

A cryogenic vacuum pump, designed to lower the base pressure from 2 × 10-6 Torr to 3 × 10-7 Torr was installed in the Bevatron in February 1972. The ~ 11,000 ft3 vacuum volume contains > 100,000 ft2 of outgassing surface and is pumped with twenty-four 32-in. oil diffusion pumps. Nine cryopanels (90 ft total) were distributed around the 360-ft circumference, increasing pump capacity by 400,000 l/s for condensibles at 80°K and 140,000 l/s at 20°K. Benefits include faster pumpdowns, improved beam stability, and higher intensities.

A Cryogenic Pumping System Proposed for the Bevatron

A cryogenic pumping system capable of pumping 300, 000 1/sec of nitrogen is proposed for the Bevatron to decrease the base pressure from ~2x10-6 to ~2 x 10-7 torr. The Bevatron consists of approximately 10,000 ft3 of free volume with approximately 15,000 ft2 of free outgassing area. The magnet pole tips, which consists of 1/2-in. laminations, add a potential 80,000 ft2 of outgassing area. The design calls for an approximately 360-ft-long, 20°K surface shielded by an 80°K surface strung along the inside perimeter of the Bevatron. Initial design considerations indicate that radiant heat flux from the 80°K surface is a prime design factor which could greatly affect the operating and installation costs of 80°K refrigeration. A two-dimensional Monte Carlo type program was devised and used to optimize designs with maximum nitrogen pumping speed and minimum 80°K shield area to reduce the refrigeration costs.

Measurement and Optimization of the Emittance of a 300-ns 250-A 3.4-MeV Electron Beam

Author(s): Allison, R.W.; Beal, J.W.; Everett, W.L.; Guggemos, J.R.; Lamb, W.A.S.; Richter, R.M.; Sherwood, W.A.; Spoerlein, R.L.; Tanabe, J.; Wright, R.E.; Zajec, E.

Copper-Tape-Wound Edge-Cooled Solenoid

Construction details and tests of a 10-cm-ID and 26.35-cm-long copper-tape-wound solenoid are described. Magnet measurements at 35 kW indicate an axial-field line integral of 193 kG-cm and a transverse-field line integral, measured on the geometric axis, of less than 0.1% of the axialfield integral.