Development of high-resolution ERDA with double MCP system and determination of detection limit for H and D

A double MCP (micro channel plate) system is developed for the improvement of detection limit in HERDA (high-resolution elastic recoil detection analysis) for hydrogen (H) and its isotope. One MCP detects the recoils of hydrogen (or deuterium (D)), the other one detects the secondary electrons emitted from stopper foil. While the dark current noise is reduced down to 2%, the detection efficiency still remains as 80%. The improved detection limit for H and D achieved ∼6.3 × 1019 atoms/cm3 (∼0.06 at.%) for 360 s and ∼2.3 × 1020 atoms/cm3 for 114 s, respectively. It is also found that the contributions of recoils of other light elements to the detection limit are crucial from the comparison with the previous study, in which both H and D are included in the samples. The developed system successfully determines the D depth profile in a SiO2 thin film (t = 5 nm) caused by the D2 annealing.