4 Irradiation Facility and Setup

The heavy-ion species used for the SEE studies on this product were provided and delivered by two facilities:

• Michigan State University (MSU) Facility for Rare Isotope Beams (FRIB) using a linear accelerator and an advanced electron cyclotron resonance (ECR) ion source. At the fluxes used, ion beams had good flux stability and high irradiation uniformity as the beam is collimated to a maximum of 20mm x 20mm² square cross-sectional area for the in-vacuum scintillator. Uniformity is achieved by scattering on a Cu foil and then performing magnetic defocusing. The flux of the beam is regulated over a broad range spanning several orders of magnitude. For these studies, ion flux of 8.36x10⁴ to 1.14x10⁵ ions/cm²·s was used to provide heavy-ion fluences of 1.00 x 10⁷ ions/cm².
• Texas A&M University (TAMU) Cyclotron Radiation Effects Facility using a superconducting cyclotron and an advanced electron cyclotron resonance (ECR) ion source. At the fluxes used, ion beams had good flux stability and high irradiation uniformity over a 1-in diameter circular cross-sectional area for the in-air station. Uniformity is achieved by magnetic defocusing. The flux of the beam is regulated over a broad range spanning several orders of magnitude. For these studies, ion flux of 1.04x10⁵ to 1.10x10⁵ ions/cm²·s was used to provide heavy-ion fluences of 1.00x10⁷ ions/cm².

For the experiments conducted on this report, there were two ions used, ¹²⁹Xe and ¹⁰⁹Ag. ¹²⁹Xe was used to obtain LET_EFF of 50.5 MeV × cm² / mg. ¹⁰⁹Ag was used to obtain LET_EFF of 48 MeV × cm² / mg. The total kinetic energies for each of the ions were:

• ¹²⁹Xe = 3.225 GeV (25MeV / nucleon)
  • Ion uniformity for these experiments was 97.3%
• ¹⁰⁹Ag = 1.634 GeV (15 MeV/nucleon)
  • Ion uniformity for these experiments was between 91 and 92%

Figure 4-1 shows the TPS7H60x5-SEP Evaluation Board used for the data collection at both facilities. Although not visible in this photo, the beam port has a 1mil Aramica window to allow in-air testing while maintaining the vacuum within the accelerator with only minor ion energy loss. The in-air gap between the device and the ion beam port window was maintained at 70mm for all runs at MSU and 40mm for all runs at TAMU.

Figure 4-1 Photograph of the TPS7H60x5-SEP Evaluation Board in Front of the Heavy-Ion Beam Exit Port at the Michigan State FRIB