4 Irradiation Facility and Setup

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

• Texas A&M University (TAMU) Cyclotron Radiation Effects Facility using a K500 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 9.32 × 10⁴ to 1.31 × 10⁵ ions/cm²/s was used to provide heavy-ion fluences of 1.00 ×10⁷ ions/cm². The TAMU facility uses a beam port that has a 1-mil Aramica window to allow in-air testing while maintaining the vacuum within the particle accelerator. The in-air gap between the device and the ion beam port window was maintained at 40 mm for all runs.

• Michigan State University (MSU) Facility for Rare Isotope Beams (FRIB) using a K500 superconducting cyclotron (KSEE) 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 40 mm × 40 mm square cross-sectional area for the in-air and vacuum scintillators. 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 5.89 × 10⁴ to 1.11 × 10⁵ ions/cm²/s was used to provide heavy-ion fluences of 1.00 × 10⁷ ions/cm². The KSEE facility uses a beam port that has a 3-mil polyethylene naphthalate (PEN) window to allow in-air testing while maintaining the vacuum within the particle accelerator. The in-air gap between the device and the ion beam port window was maintained at 60 mm for all runs.

For the experiments conducted on this report, 2 ions were used; ¹⁰⁹Ag (TAMU) and ¹⁰⁹Ag (KSEE). Both were used to obtain LET_EFF of ≈ 48 MeV·cm²/mg. The total kinetic energies for the ions were:

• ¹⁰⁹Ag (TAMU) = 1.635 GeV (15 MeV/nucleon) – Ion uniformity for these experiments was 94%

• ¹⁰⁹Ag (KSEE) = 2.125 GeV (19.5 MeV/nucleon) – Ion uniformity for these experiments was 91%

Figure 4-1 and Figure 4-2 shows the TPS7H401xEVM used for data collection at the TAMU facility. 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.