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Injector Accelerators

FMT developed and delivered a 10-keV, 100 mA injector for the University of Maryland Electron Ring (UMER), a recirculating accelerator being developed as a model for a new class of very high current accelerators (see UMER web site). FMT also designed, developed, and delivered a separate, multi- purpose beam diagnostic chamber for use with UMER.

The E-gun includes a micrometer-controlled variable A/K gap for adjustable beam current, a gate valve and an ion pump. A built-in Rogowski-type current monitor is also included. A rotatable calibrated aperture plate with six masks is built in. The plate includes a pepperpot and a five-beamlet aperture as well as several round apertures. A small window allows a direct view of the particular aperture in place. The E-gun is bakeable up to 250^o C. The solenoid mount is to the right and the HV deck is visible on the left in the photograph of the E-gun.

UMER Injector E-gun

Beam Diagnostic Chamber

The multi-purpose beam diagnostics chamber is shown in the photograph. With an 8-inch ID, it is designed to measure horizontal and vertical emittance with a slit-wire technique. A retarding-field energy analyzer is included to measure energy and energy spread. A movable phosphor screen with 1.5 meter travel is also included for insertion into the complete injector as well as initial measurements of the E-gun. In addition, a Faraday cup and pepperpot are supplied. Three transverse viewing ports are included. There are 11 ports in this bakeable system, including a port for the 60 l/s ion pump. Where appropriate, precision linear motion feedthroughs with 4.25 inch travel for remote insertion and extraction are provided.

FMT UMER Injector Layout

The injector layout shows the location of major elements. FM Technologies supplied the injector system up to but not including the Y-shaped injection chamber. The system includes some components supplied by UMD. The Helmholtz conductors (HC) are placed in a rectangular array for earth field compensation with minimum field error. The drawing shows the original concept, which included two Panofsky quadrupoles pulsed sequentially, Pan1 for the injected beam and Pan2 for the ring beam. The short dipoles (SD) are for small steering corrections.