FRANK LABORATORY OF NEUTRON FRANK LABORATORY OF NEUTRON PHYSICSPHYSICS

ION BEAM ANALYSISION BEAM ANALYSIS

STANCIU-OPREAN LIGIASTANCIU-OPREAN LIGIA

SUPERVISOR DR. KOBZEV ALEXANDERSUPERVISOR DR. KOBZEV ALEXANDER

MAIN PROPERTIES OF VAN DE GRAAF MAIN PROPERTIES OF VAN DE GRAAF ACCELERATORACCELERATOR

Accelerated ions 1H+, 2H+, 3He+, 4He+,12C+, 14N+, 16O+

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

2

12

122

122 ]

cos)sin([

21

MM

MMMk

M1 –mass of incident particleM1 –mass of incident particle

М2 –М2 –mass of scattering atommass of scattering atom;;

--scattering anglescattering angle

Backscattering crossectionBackscattering crossection

221

22

2221

221

2

2

0

221

sin

]sincos[

2sin

1)

2(

MM

MMM

E

ezz

d

d

Z1 – the atomic number of incident particles;

Z2 – the atomic number of scattered atom;е – the electronic charge;

E0 – the energy of the projectile immediately before scattering

RBS SPECTRUM FOR W/La/Si – SAMPLERBS SPECTRUM FOR W/La/Si – SAMPLE

PIXE MethodPIXE Method

• Moseley lawMoseley law

frequency of X-rayfrequency of X-ray;;Rc –Rydberg’s constantRc –Rydberg’s constant;;

ZZ – –atomic numberatomic number;;SnSn – – screening constant screening constant;;nn – –main quantum numbermain quantum number;;

n

SZ

Rn

c

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 0.015

Fe 0.40

Cu 0.003

Zn 0.01

As 0.001

Zr 0.003

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 10-15 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 %.