2016 SVC TechCon

Sessions Speakers Exhibitors Show Specials Floor Plan Buzz

Fabrication of PMMA/Metal Multilayers for Soft Gamma-Ray Telescope Lenses (Room Exhibit Hall)

11 May 16
3:30 PM - 3:50 PM

Tracks: Poster Presentation, Poster Presentation, Poster Session

Thin-film multilayer structures were fabricated to demonstrate the feasibility of channeling and concentrating soft gamma rays (above 100 keV). These multilayer structures will be used in concentrating lenses for soft gamma-ray telescopes. Gamma rays can be channeled via total external reflection in multilayer structures that consist of alternating layers of a low-density material (PMMA) and a high-density materials (gold-palladium). The fabrication of these multilayers was investigated using two methods: (1) spin-coating for PMMA (at atmospheric pressures)/magnetron sputtering for the metal and (2) ablation of PMMA using pulsed-laser deposition (PLD) and deposition of the metal by magnetron sputtering. For spin coating, we studied the effects of the wt% PMMA in toluene/MeOH and spin speed on surface roughness. The RMS roughness varied between 3 and 10. A multilayer stack was then fabricated with 14 PMMA layers (~250 nm thick) and 15 Au/Pd layer (80 nm thick). Examination in the SEM after FIB cross-section showed a high degree of smoothness can be obtained. Similar structures have been fabricated using the PLD/sputtering method, and both have been tested for gamma-ray channeling by exposing them to a finely collimated (~0.3 arcmin) beam of 122 keV photons.