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 1.02 × 10⁴ to 1.12 × 10⁵ ions / cm² × s were used to provide heavy-ion fluences of 9.97 × 10⁶ to 1.00 × 10⁷ ions / cm².

For the experiments conducted on this report, there were three ions used, ¹⁰⁹Ag, ⁸⁴Kr, and ⁶³Cu. ¹⁰⁹Ag was used to obtain LET_EFF of 43 and 48MeV × cm² / mg. ⁸⁴Kr was used to obtain LET_EFF of 30.6MeV × cm² / mg. ⁶³Cu was used to obtain LET_EFF of 20.3MeV × cm² / mg. The total kinetic energies for each of the ions were:

• ¹⁰⁹Ag = 1.634 GeV (15 MeV/nucleon)

• ⁸⁴Kr = 1.259GeV (15MeV / nucleon

• ⁶³Cu = 0.944GeV (15MeV / nucleon)

Figure 4-1 shows the DRV8351-SEP 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 between 10 - 40mm for all runs to achieve different effective LETs.

Figure 4-1 Evaluation Board in Front of the Heavy-Ion Beam Exit Port

Figure 4-2 Output of Beam