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 250o 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.