FRANK LABORATORY OF NEUTRON PHYSICS ION BEAM ANALYSIS STANCIU-OPREAN LIGIA SUPERVISOR DR. KOBZEV ALEXANDER

MAIN PROPERTIES OF VAN DE GRAAF ACCELERATOR Accelerated ions 1 H +, 2 H +, 3 He +, 4 He +, 12 C +, 14 N +, 16 O + Energy range 0.7 – 3.5 MeV Energy spread` < 500 eV Accuracy in energy 1 keV Beam intensities H – 30  A He – 10  A C, N, O ~ 1  A Beam lines 6 Height of the accelerating tube 6 m Diameter of the tank 2.5 m Pressure in the tank 8 at

Rutherford Backscattering Spectrometry M1 –mass of incident particle М2 –mass of scattering atom;  -  scattering angle

Backscattering crossection Backscattering crossection Z 1 – the atomic number of incident particles; Z 2 – the atomic number of scattered atom; е – the electronic charge; E 0 – the energy of the projectile immediately before scattering

RBS SPECTRUM FOR W/La/Si – SAMPLE

PIXE Method PIXE Method Moseley lawMoseley law  frequency of X-ray; Rc –Rydberg’s constant; Z –atomic number; Sn – screening constant; n –main quantum number;

PIXE SPECTRUM FOR ENVIRONMENT SAMPLE

RBS PIXE C 34 N 28 О 19 F 3.4 Na 5.1 Mg 1.8 Al 3.3 Si 3.5 S 0.02 K 0.2 Ca 1.2 Mn Fe 0.40 Cu Zn 0.01 As Zr Ba 0.02 Sample N1

Conclusion 1.RBS and PIXE are undamaging methods. 2. Any element with mass from 1 up to 200 can be identified exactly. 3. The depth resolution reaches 2-3 nm. 4. The actual accessible depth for analysis is near 2-3 mkm for He-beam and is mkm for proton beam. 5.The sensitivity is different for the various samples, but for heavy elements it can be less, than 0.1 atomic %.