4 Irradiation Facility and Setup

The heavy-ion species used for the SEE studies on this product were provided and delivered by the 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 2.74 × 10⁴ to 1.00 × 10⁵ ions / cm² × s were used to provide heavy-ion fluences of 1.00 × 10⁷ ions / cm².

For the experiments conducted on this report, there were two ions used, ¹⁰⁹Ag, and ¹⁶⁵Ho. ¹⁰⁹Ag was used to obtain LET_EFF of 48 or 58 MeV × cm² / mg. ¹⁶⁵Ho was used to obtain LET_EFF of 75 MeV × cm² / mg. The total kinetic energies for each of the ions were:

• ¹⁰⁹Ag = 1.634 GeV (15 MeV/nucleon)
  • Ion uniformity for these experiments was 95%
• ¹⁶⁵Ho = 2.474 GeV (15MeV / nucleon)
  • Ion uniformity for these experiments was between 81 and 98%

Figure 4-1 shows the TPS7H60x5-SP Evaluation Board used for the 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. The in-air gap between the device and the ion beam port window was maintained at 40mm for all runs.

Figure 4-1 Photograph of the TPS7H60x5-SP Evaluation Board in Front of the Heavy-Ion Beam Exit Port at the Texas A&M Cyclotron