In order to provide a variety of ion species to the BNL relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory facilities on a pulse-to-pulse basis, the BNL RHIC electron beam ion source (EBIS) will use injection of primary “seed” ions from external low charged ion sources. As part of the prototype for the RHIC EBIS low energy beam transport line, a switchyard for seed ion injection and extracted EBIS ion beams has been constructed. The ion injection line includes a hollow cathode ion source (HCIS), four quadrupole lenses, a switchyard, gridded lenses, and other deflection optics. The HCIS is based on one obtained from CEA Saclay [B. Visentin et al., Phys. Scr., T 71, 204 (1997).] and has been used in bench studies in the production of low charged metal and gas ions, as well as in BNL test EBIS injection studies for the production of highly charged ions. The HCIS geometry and extraction optics have been modified to be able to reach the output currents necessary to seed the test EBIS. Ion currents greater than 60μA Cu+ and 130μA Ne+ have been extracted from the modified HCIS at 12–15kV and plasma aperture of 1–1.5mm. The HCIS discharge is initiated by a rf coil and can be operated stably at pulse rates from 1to100Hz. Measurement of the emittance of injector beam before and after the injection switchyard will be provided, as well as results from ion injection into the test EBIS using the new injector configuration.

A new, simple method for making Nb/sub 3/Sn-Nb/sub 3/Sn superconducting joints is described in this paper. Joints with resistance 5/spl times/10/sup -13/ /spl Omega/, which is good enough for NMR spectrometers, have been fabricated, using a simple and reproductive procedure. An in situ joint test system and joint test results are presented.<>

A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented

A new design of a continuous-type helical electrostatic qundrupole (HESQ) ' p 1s resented. It is expected that the performance in its quasi-octupole mode of operation (with all four rods at sasme positive voltage) will be superior com- pared with the performance of the norrnal mode of opera- tion as a quadrupole. The main advantage is the climina- tion of chromatic effect,5 which distort the beam shape in phase space. Construction of this HESQ is in progress at. Texas Accelerator Center.

The helical electrostatic quadrupole (HESQ) lens has been proposed as a low energy beam transport system which permits intense H/sup -/ beams to be focused into a radio frequency quadrupole (RFQ) without seriously increasing the beam's emittance. A stepwise continuous HESQ lens has been constructed, and preliminary tests have shown that the structure does provide focusing. In order to understand the transport properties of this device, further detailed studies have been performed. Emittances were measured 3.5 cm from the end of the HESQ at two different voltages on the HESQ electrodes. A comparison of these experimental results with a linear model of the HESQ beam transport is made.< >

A program has been started at the Texas Accelerator Center (TAC) to develop H/sup -/ ion sources for its 500-keV radio frequency quadrupole (RFQ) program. The group is working on both magnetron and volume ion sources. A tilted extraction system has been designed for the magnetron source which corrected a 25-mrad angular offset in the extracted beam. An LBL type volume H/sup -/ ion source has been designed and constructed. To date, the plasma generator of the source has been tested, with extracted beam tests beginning during 1991.<>

We have constructed a new type of four-rod Radio Frequency Quadrupole to operate at 473 MHz. Four-rod structures have not been previously built for such a high frequency. The RFQ is designed to accelerate 10 rnA of H- ions from 30 keY to 0.5 MeV. The rf measurements and beam test of the RFQ have been performed success­ fully. Here, we present operational results of the RFQ system including measurements of the beam current, the required rf power, energy, energy spread, and emittance.