Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection
The sensitivity of hydrogen elastic recoil detection (ERD) is usually limited by the low energy background in the ERD spectrum. This background varies substantially from sample to sample and is related to the amount of hydrogen present on or near the sample surface. A number of 4.5 MeV He 2+ hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z carbon to high Z tungsten carbide to observe the effects of multiple scattering and double scattering within the sample material. The effect of different ERD geometries is also studied. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. The contributions of other processes are also discussed.