STATUS OF THE PNPI ELECTROSTATIC ACCELERATOR
PNPI participants: V.M. Lebedev, V.A. Smolin, B.B. Tokarev, A.G. Krivshitch, and G.E. Gavrilov;
Ioffe Phisico-Technical institute of RAS participants: E.I. Terukov, Yu.K. Undalov,
V.Kh. Kudoyarova, and V.K. Gusev;
Kurnakov Institute of General and Inorganic Chemistry of RAS participant: S.A. Kozyukhin.
1. Analytical complex on the base of the electrostatic accelerator
There are two working small accelerators in PNPI: an electrostatic accelerator (ESA) [1, 2] and a neutron
generator. The machines of such a type are used widely both in scientific and in applied investigations.
Researches in the fields of solid state physics, semiconductors, and element analyses of the matter are carried
out at these accelerators. The ESA is shown in Fig. 1. Its main parameters are given in Table 1. The ion tract
with the length of 15 m has ion-optics elements, beam control devices, and an analysing magnet that makes it
possible to form and to lead to the target an ion beam with the desired size and intensity, as well as to
stabilize its energy [1, 2].
An experimental installation for element analyses was installed at the PNPI electrostatic accelerator. The
installation consists of a target chamber (Fig. 2), Si(Li) and crystal-diffraction spectrometers for detection of
X-rays [3], planar Si detectors for detection of ions, and a Ge(Li)-spectrometer for detection of γ-rays.
Spectra from detectors are collected with CAMAC electronics. Parameters of the experimental installation
are also given in Table 1.
Fig. 1. The electrostatic accelerator
2. Methods of nuclear microanalysis on the ESA beams
Beams of light ions were used for microanalyses of solids by means of nuclear physics techniques: the
proton induced X-ray emission (PIXE), the nuclear reaction analysis (NRA), and the Rutherford
backscattering spectrometry (RBS). The element composition of bulk materials, the structure of films and
outer layers of solids, and the concentration profiles are generally considered in the microanalysis of solids
(Fig. 3).
Nuclear physics techniques are nondestructive, high sensitive and precise. However, the possibilities of
the PIXE, RBS, and NRA methods for detection of elements with low and high atomic numbers and for
measurements of their contents in samples are different. The RBS is more sensitive to heavy elements
Table 1
Parameters of the analytical complex on the base of the ESA
Parameter
Accelerating particles
Ion energy
Energy resolution ΔE/E
Energy spread of the beam
Beam intensity on a sample
Value
Protons, deuterons
(0.3 – 1.3 ) MeV
10-4
~ 100 eV
(0.1 – 3·104 ) nA
Precision of beam intensity measurements
Beam diameter on the sample
Vacuum in the target chamber
~1%
(1– 8) mm
10-6 Тоrr
Energy resolution of the spectrometers
Crystal-diffraction at EX = 6.4 keV
Si(Li) at E X = 6.4 keV
Ge(Li) at Eγ = 1.33 MeV
For charge particles at Eα = 2.5 MeV
30 eV
190 eV
2.1 keV
8 keV
Table 2
Nuclear reactions used to determine the isotope composition
Nucleus
Н
Li
7
Li
10
B
11
B
2
6
12
C
C
14
N
13
15
N
O
16
18
O
F
19
19
F
Nuclear reaction
D(d,p)3H
Li(d,)4He
7
Li(p,)4He
10
B(d,0)8Be
11
B(p,0 )8Be
11
B(p,1 )8Be
12
C(d,p)13C
13
C(d,p)14C
14
N(d,p)15N
14
N(d,0 )12C
14
N(d,1 )12C
15
N(p,)12C
16
O(d,p0 )17O
16
O(d,p1 )17O
16
O(d,)14N
18
O(p,)15N
19
F(p,)16O
6
19
F(p,γ)16O
QR-value,
MeV
4.033
22.374
17.347
17.822
8.586
5.650
2.722
5.947
1.305
13.579
9.146
4.864
1.918
1.049
3.111
3.980
8.114
8.114
Incident beam
energy, keV
950
900
670
900
700
700
1000
640
970
900
900
800
900
900
900
730
1250
Cross section,
mb/sr
6.0
4.5
0.4
0.38
0.12 (0)
90 (1)
30
0.4
6.1 (p5)
0.07 (0)
0.86(1)
15
0.74 (p0)
4.5 (p1)
5.1
15
0.5
1250
Resonance reaction
(with the atomic number Z greater than 30). In favorable cases, 1012 at/cm2 can be detected. In spite of lower
sensitivity for high Z elements, the PIXE can give better element resolution than the RBS. Nuclear reactions
are efficient for detection of low Z (Z < 14) impurities, and hence complement the RBS and PIXE (Table 2).
The RBS and NRA techniques can give the depth distribution of elements in a sample. The simultaneous
usage of these methods allows one to obtain detail and precise information on the element composition from
one experiment. Analytical characteristics of the nuclear techniques are given in Table 3.
Fig. 2. The target chamber
Fig. 3. Typical sphere of the microanalysis using nuclear physics methods with ions
Table 3
Analytical characteristics of the nuclear microanalysis techniques
Parameter
Elements identified
Element resolution ΔZ
Sensitivity
Precision
Thickness of the investigated layers
Depth resolution
Lateral resolution
Value
2
H, Li – U
1
(10-1 – 10-5) %
(3 – 5 ) %
(0.01 – 10) μm
< 10 nm
± 0.5 mm
3. Main results of investigations on the ion beams
The main results of investigations of solids carried out at these accelerators during last 6 years include:
 Aging investigations of straw drift-tubes, proposed for experiments at the LHC [4, 5].
 Investigations of the composition, morphology and structure of mixed layers deposited onto surfaces
after a preliminary carboboronization procedure (B/C:H layers deposition) and subsequent deuterium
plasma-wall interaction in different areas of the Globus-M spherical tokamak after more than 8000
pulses (more than 800 s) [6–8];
 Studying of the composition and photoluminescence of amorphous hydrogenised silicon films doped
with erbium and oxygen (α-SiOX:H<Er, O>) [9, 10];
 Studying of the synthesis, composition and surface composition of the amorphous As2Se3 and As2S3,
modified with complex compounds Ln(thd)3 (Ln = Eu, Tb, Er, Yb) [11–13];
 Investigations of doping influence on the structure and optical characteristics of Ge2Sb2Te5
amorphous films [14].
References
1. V.B. Andrienko, A.N. Dyumin, V.M. Lebedev et al., Preprint LNPI-872, L., 1983. 16 p.
2. V.M. Lebedev et al., Proc. of XIII International conference on electrostatic accelerators. Obninsk,
Russia, 1999, p. 60.
3. V.B. Andrienko, A.N. Dyumin, V.M. Lebedev et al., Prib. Tekhn. Eksp. 3, 51 (1991).
4. V.K. Gusev еt al., Journ. of Nucl. Materials 386-388, 708 (2009).
5. V.K. Gusev et al., Nuclear Fusion 49, 095022 (2009).
6. V.K. Gusev et al., Nuclear Fusion 49, 104021 (2009).
7. V.M. Lebedev et al., Bulletin of the Russian Academy of Sciences: Physics 71, 1327 (2007).
8. A.G. Krivchitch, V.M. Lebedev, Nucl. Instr. Meth. A 381, 167 (2007).
9. Yu.K. Undalov et al., Semiconductors 42, 1327 (2008).
10. Yu.K. Undalov et al., Semiconductors 45, 1604 (2011).
11. S.A. Kozyukhin et al., Physics and Chemistry of Solids 68, 1117 (2007).
12. V.Kh. Kudoyarova et al., Semiconductors 41, 914 (2007).
13. V.Kh. Kudoyarova et al., Physica Status Solidi C 7, 881 (2010).
14. S.A. Kozyukhin et al., Physica Status Solidi C 8, 2688 (2011).