New Developments in Accelerator Technology at LASL

The objective of the PIGMI (Pion Generator for Medical Irradiations) program at LASL is to develop the technology to allow the construction of smaller, less expensive and more reliable proton linacs for medical applications. Now in the final year of a three year program, a prototype accelerator is being prepared for beam tests. The high electric field gradients required have already been achieved in PIGLET, an accelerator test cavity. The injector for the prototype features a compact ion source and accelerating column assembly, a double frequency buncher, a tape wound edge cooled solenoid magnet and a series of versatile beam diagnostic boxes. The control system makes use of distributed microprocessor control with a powerful operators console. This system is currently being used to tune the injector and to develop diagnostic tools for evaluation of the performance of the prototype. The accelerating cavity itself is a copperplated 450-MHz structure featuring an alternating phase focused section followed by a transition to a conventional drift tube structure employing permanent magnet focusing. An exciting new rf quadrupole structure (RFQ) which provides an alternate technique for achieving low energy injection will be tested with beam using the PIGMI prototype as a test stand. The design features and current status of the PIGMI program are discussed.