The Lujan Center at the Los Alamos National Laboratory's Neutron Science Center (LANSCE) is a spallation neutron source where research in materials and biological sciences is conducted on time-of-flight neutron scattering spectrometers on eleven beam lines. Execution of an experiment on a neutron spectrometer involves 1) control of the sample environment equipment, 2) measurement of the scattered neutrons, and 3) operation of the beam line itself. This paper describes the automation and coordination of these functions that is essential to effective conduct of experiments.

Assessing superconducting technology for potential upgrades to existing proton accelerators as well as applications to future high-current machines necessitates developing expertise in the processing and handling of multicell cavities at useful frequencies. In order to address some of these technological issues, Los Alamos has purchased a 4-cell 805-MHz superconducting cavity from Siemens AG. The individual cavity cells were double-sided titanium heat-treated after equatorial welding, then the irises were welded to complete the cavity assembly. The resulting high RRR (550-730) in the cells enables stable operation at higher cavity field levels than are possible with lower RRR material. Additionally, the high thermal conductivity of the material is conducive to RF and high peak power processing. The cavity was also cleaned at Los Alamos with high-pressure water rinsing. Results from the initial cavity tests, utilizing various processing techniques, are presented

We have designed and are building a subpicosecond electron injector. The injector is based on an 8 MeV photoinjector, used previously at Los Alamos in the APEX experiment. The nominal design includes magnetically compressing a 20 ps long, 3 nC bunch to a FWHM bunch length of 2/3 ps (peak current in excess of 3 kA) using a four dipole chicane buncher. The geometrical averaged transverse normalized transverse emittance after compression is about 15 /spl pi/ mm mrad.

Assessing superconducting technology for potential upgrades to existing proton accelerators as well as applications to future high-current machines necessitates developing expertise in the processing and handling of multicell cavities at useful frequencies. In order to address some of these technological issues, Los Alamos has purchased a 4cell 805-MWz superconducting cavity from Siemens AG. The individual cavity cells were double-sided titanium heat-treated after equatorial welding, then the irises were welded to complete the cavity assembly. The resulting high RRR (550-730) in the cells enables stable operation at higher cavity field levels than are possible with lower RRR material. Additionally, the high thermal conductivity of the material is conducive to rf and high peak power processing. The cavity was also cleaned at Los Alamos with high-pressure water rinsing. Results from the initial cavity tests, utilizing various processing techniques, are presented. In the interest of obtaining high accelerating fields, the cavity manufacturing processes of inspection, forming, machining, welding, firing, and etching were stringently specified [2]. Additional processing refinements were also added, based on LANL research in field emission in single cell cavities. Augmentations to the standard cavity processing used by the manufacturer included a 0.5-pm filter and heat exchanger for the recirculating etch chemistry, a long (90 hours) spray rinse with ultrapure water, and High Purity Liquid Chromatography grade (HPLC) methanol rinsing. The original manufacturer cleaning was supplemented by additional cleaning at Los Alamos that included high-pressure ultrapure-water cleaning of the cavity and components and microscopic inspection of ancillary components and flanges.

Single-cell, 3 GHz cavities are being tested to refine cavity processing and assembling procedures. Certain of these results indicated a cavity contamination problem, especially after high-field operation. In this instance, the observed behavior of poorly performing cavities indicated that indium contamination may be responsible. The standard chemical polishing treatment was modified to include a 10 minute pretreatment with pure concentrated nitric acid before the standard 2 minute dip in 1, 1, 1. Preliminary results from five cavity tests indicate that this modification may decrease the number of cavity tests that fall in the lower lobe of the performance distribution.< >

The authors describe the results of wire measurements of several prototype DARHT cavities. The measurements reported cover MOD0 with ferrites removed, measurements with drive rods in place with various terminations, and measurements with compensation cans. Measured impedances are compared with AMDS code predictions. The effects of various rod terminations and compensation resistors on cavity impedances are shown.<>