Accelerator Facility

The accelerator laboratory occupies nearly 6000 square feet in the basement of Volcanology, located adjacent to the main Physics building, known as Willamette Hall. Main subdivisions of this facility include accelerator vault, target room, control room, machine shop, electronics shop, and chemistry preparatory room. Faculty offices and an additional 600 square feet of laboratory space are maintained in the main Physics building.

The accelerator is a HVEC KN-4000 Van de Graaff insulated with SF6 . A voltage upgrading kit allows operation to an energy of 5.2 MeV. The accelerator is equipped with an ORTEC pulsed terminal with duoplasmatron ion source, gridded einzel lens, and preacceleration klystron beam bunching. Post-acceleration chopping is also available. The duoplasmatron is capable of injecting several hundred microamperes of H+ ions into the accelerator. For nanosecond-pulsed beam work, bunched beams of protons, deuterons, and alpha particles are routinely available with time-averaged intensities up to 5 microamperes. Beam-pulse widths achieved at the target range from 1.0 to 2.5 ns, FWHM, depending on the ion species. Pulse repetition periods ranging from 0.5 to 16 microseconds can be chosen remotely.

The target room is equipped with 6 beam-tube extensions, with provision for a seventh. The zero-degree beam tube is equipped with a fast, 50-ohm Faraday cup which is used for preliminary adjustment of the pulsed beam. One beam line is used for neutron studies. A single-detector neutron time-of-flight spectrometer with a flight path of up to 10m at 0o can be used with this station. This beam line is presently equipped, however, with a 16-detector, linear array and associated time-of-flight electronics, an automated luggage lift, and flexible shielding and neutron collimators. It is currently used for explosives-detection studies. Another beam line is permanently dedicated to proton microprobe investigations.

The laboratory is equipped with an extensive array of fast and slow modular pulse electronics, general electronic equipment and instruments, and a variety of radiation detectors and monitors. Automated data acquisition is carried out with various CAMAC instrumentation via a GPIB crate controller.

Laboratory computing facilities include a Sun Sparc IPX workstation with several gigabytes of disc storage. The workstation is connected to the university's 10BaseT local area network and shares several disc partitions with a Sun Sparc 5 housed in the main Physics Building. A Silicon Graphics parallel processor, with a peak computational capacity exceeding 7 GFLOPS, is accessible over this network. Several NCD X-terminals are also available in the laboratory and staff offices.