Hydrogen and deuterium depth profiling by elastic recoil detection analysis

Cross section of 15N-2D nuclear reactions from 3.3 to 7.0 MeV for simultaneous hydrogen and deuterium quantitation in surface layers with 15N ion beams

“…Nuclear reaction analysis (NRA) via the 1 H( 15 N,) 12 C reaction using 15 N ion beams above the 6.385-MeV energy resonance is a well-established and powerful method for nanometer-resolved depth profiling of hydrogen ( 1 H) in the near-surface region of solids [1][2][3][4]. 15 N-1 H NRA quantitatively reveals the 1 H depth distribution in the analyzed target by registering the emitted -rays as a function of the 15 N incidence energy.…”

“…15 N-1 H NRA quantitatively reveals the 1 H depth distribution in the analyzed target by registering the emitted -rays as a function of the 15 N incidence energy. At typical beam sizes of a few mm 2 , 1 H( 15 N,) 12 C NRA depth-selectively determines the 1 H content in electrical conductors as well as in insulating samples with a sensitivity of ~110 13 cm -2 for 1 H at surfaces and ~110 18 cm -3 (~100 ppm) 1 H in the bulk within several tens of minutes, irrespective of the chemical binding state of 1 H [5]. The technique is most elegantly performed with a scintillation detector positioned behind the target outside of the analyzing vacuum system, which provides accessibility for in-situ sample characterization and manipulation through surface science instrumentation [3][4][5].…”

“…The technique is most elegantly performed with a scintillation detector positioned behind the target outside of the analyzing vacuum system, which provides accessibility for in-situ sample characterization and manipulation through surface science instrumentation [3][4][5]. Inherently, however, 1 H( 15 N,) 12 C NRA is selective only to the 1 H isotope. This limits the technique's versatility in situations when the target material contains both 1 H and 2 D, such as in the study of hydrogen isotope exchange processes in surface layers.…”

“…The latter are of profound interest in the context of plasma-surface interactions occurring in thermonuclear fusion devices [6,7] or for the elucidation of hydrogen transportation mechanisms across metal surfaces related to hydrogenation catalysis, hydrogen storage and purification [8][9][10]. Depth profiling of deuterium ( 2 D) is typically performed with 2 D( 3 He,p) 4 He NRA using 3 He ion beams of much lower energy [11], which is in turn selective for only 2 D. Synchronous analysis of 1 H and 2 D could hitherto only be achieved by elastic recoil detection (ERD) [12][13][14]. This method registers H and D recoils with in-vacuum particle detectors and often additional resolutionenhancing ion optics positioned in the forward direction [15][16][17][18], which precludes integration with 15 N NRA for 1 H, as the -ray detector should be placed as closely as possible to the analyzed target to provide sufficient sensitivity for 1 H. Thus, with the aim to expand the versatility of 15 N NRA towards analyzing materials that contain both 1 H and 2 D, we here describe a novel approach to quantify the 1 H and 2 D isotopes in near-surface layers simultaneously, using a single 15 N ion beam and the convenient -ray detection system of a conventional 15 N-1 H NRA setup without the need for additional particle detectors.…”

“…The 15 N ions of energies above 6.385 MeV used as projectiles in 1 H( 15 N,) 12 C NRA also induce the 2 D( 15 N,p) 16 N and 2 D( 15 N,n) 16 O reactions with 2 D in the target. The latter reactions release -rays of 6.13 and 7.12 MeV [19] that are well-separated from the 4.3-MeV -emission from 1 H( 15 N,) 12 C and easily detectable with virtually no background from natural radiation (see Figure 1 below).…”