A new dosimeter to improve characterization of TRIUMF proton and neutron beams:
With collaborators at the University of Waterloo, TRIUMF's PIF & NIF group has invented a new dosimeter that's proven incredibly valuable at characterizing the proton and neutron test beams available at TRIUMF’s irradiation facilities.
Neutron radiation effects testing, usually for single event effects (SEE), uses accelerator produced neutrons with a broad energy spectrum to simulate the cosmic ray or terrestrial spectrum at ground level or aircraft altitudes. The energies that are of interest are above 1 MeV, with most testing to date using the fluence of > 10 MeV neutrons for determining acceleration factors between accelerator neutrons and the terrestrial environment. The new PIF-NIF dosimeter is based on an array of SRAMs (Static Random-Access Memories) with thirty, 16 Mbit Cypress SRAMs arranged in a close-packed 5x6 array to cover an area of 36 x 36 mm. This SRAM has several key features. It does not latch-up, and the ECC can be removed and the single event upset (SEU) cross section with ECC removed is large enough at about 10-13 cm2 per bit for good sensitivity. The total error rate at a flux of 106 protons or neutrons/cm2/s is about 2500-3000/minute so good statistics can be achieved very quickly even at much lower fluxes. The new dosimeter will allow for improvements to TRIUMF’s testing facilities and methods benefiting both scientific researchers and industrial engineers in their understanding and quantification of radiation effects.