A versatile data acquisition system and the ISOL facility TRISTAN

Abstract

Abstract The on-line mass separator, TRISTAN, is located at Brookhaven's High Flux Beam Reactor. A Nielsen-type ion source, which can contain up to 8g of 235 U in an external beam with a flux of ∼2 × 10 9 n/cm 2 /s is used to generate short-lived fission products. Experiments have been constructed on two of the five available beam lines to measure β-γ and γ-γ coincidences, γ-γ angular correlations and delayed neutron emissions. A Users Group has been formed to coordinate research between University groups and BNL. Developments planned for TRISTAN include FEBIAD, surface ionization and negative-surface ionization-type ion sources, and a He-jet system as well as construction of new experimental facilities. An off-line separator, ISTU, is available for the development program. We have constructed a versatile, modular data acquisition system to service experiments on TRISTAN and other nuclear research facilities at the HFBR using CAMAC interfacing. Standard, commercially-available electronic instruments and computer programs, such as FORTRAN and system routines, are used throughout. Simple interfaces have been built to adapt non-CAMAC equipment to CAMAC input registers. Up to eight different experiments can be multiplexed on the branch highway by a fast microprogrammed branch driver with a 4096 word memory. The branch driver delivers pre-processed data to a bus which links devices such as a central processor, 1 megaword core memory, tape drives, discs, display processor and terminal. The following features are offered: two 8192 channel pulse height analyzers, a 3-parameter coincidence unit, 4 multiscalers, a timed sequence of delayed γ-ray spectra (33 spectra of 4096 channels each), a 2-parameter (pulse height versus time-of-flight) analyzer, 16 scalers and 24 experimental interlocks. Up to 100 different spectra are available to users for display during an experiment. Event mode recording on magnetic tape and direct sorting into the 1 megaword array are used as appropriate. A master program, almost entirely written in FORTRAN, allows users to control and monitor each experiment with simple mnemonic codes. Analysis of the data is carried out on a companion computer devoted to data processing, allowing rapid sorting, plotting, listing and analysis of data.