Non-desctructive quantitative Hydrogen Analysis

Methode:

The method uses the nuclear reaction  

15N + 1H -> 12C + 4He + γ (4,43 MeV)

With this Resonant Nuclear Reaction Analysis (RNRA) hydrogen concentrations can be obtained from near surface layers of solids without a standard by measuring of the γ-rays. Because of the narrow resonance at the 15N-energy of 6.385 MeV the depth in the material where the reaction takes place can be varied by increasing the incidence energy for obtaining a depth profile.

 

 Gamma-Resonanz für die Wasserstoffanalyse


 Properties of the hydrogen analysis beamline at the 5 MV-Tandem:

  • Incident beam:
15N2+
  • Energy:
6.3 - 12 MeV
  • Beam current:
10 - 50 nA
  • Beam spot:
1 - 100 mm2 
  • Detection limit:
0,02 at%  (200 ppm)
  • Analysing depth:
up to 5 µm (depending on material)
  • Depth resolution:
about 8 nm (Si), minimal 1 nm (grazing incidence )
  • Measured quantity
yield of the 4,43 MeV γ-rays
  • Detector:
4" x 4 " BGO

Results: 

Wasserstofftiefenprofil in GaAs
Example 1:
Hydrogen depth profile in GaAs with 1 nm resolution
Wasserstofftiefenprofil in DLC Schichten
Example 2:
Hydrogen concentrations in DLC layers, made by PECVD using different parameters  

Experimental Setup:

Experimenteller Aufbau zur Wasserstoffanalyse