Laboratory of accelerator facility

Сокращенное название: LAF

Телефон: +7 495 939 25 07



Laboratory of accelerator facility

The Laboratory of accelerator facility (LAF) was organized in 1995 on the base of three charged particles accelerators: 120-cm cyclotron P-7, electrostatic (Van de Graaf) generator accelerator EG-8 and cascade Cockroft-Walton accelerator KG-500. All these accelerators were designed, developed and put into operation in the late 1950s and the early 1960s. Scientists of a number of SINP departments active use accelerators in their research in the field of fundamental physics, applied physics and allied sciences along with learning goals during the eduction of the students of MSU Physics Physics Department.

From the very beginning of the Laboratory it's head is PhD. Andrey Spassky.

Description of chrged particles accelerators:

I. 120 cm cyclotron (of P7 type) is intended for acceleration of light ions with А = 1-4 up to energy of 7,8 MeV/nucleon:
protons up to 5÷8 MeV,
deuterons up to 10÷16 MeV,
Helium-3 up to 15÷24 MeV,
alfa-particles up to 20÷30 MeV.
Beam current is up to 60 micro ampere, ejected beam current is up to 10 micro ampere.
Protons and alfa-particles are mainly accelerated particles, deuterons and Helium-3 are accelerated from time to time.

The accelerator is used for scientific research in the field of fundamental nuclear physics of medium energy and for different tasks in the applied and allied areas, for instance:
1. Backward scattering methods are used for elemental analysis of the near-surface layers of the materials.
2. Nuclear reactions are used for non-destructive analysis of some elements' content in biological samples.
3. By means of fast particles produced during nuclear reactions instruments based on silicon semiconductor detectors are tested and calibrated.
4. Short-lived isotopes are used for medical and other purposes.

Protons and alfa-particles backward scattering methods is used for profiling of oxygen content in alloy steels, for studies of structural materials nitriding, other purposes.

Products of the reactions occured in thin biological and agrochemical samples and selectively separated by means of specific nuclear reactions. It is possible to determine content of boron, carbon, nitrogen, oxugen, sulphur and other light elements' isotopes within the accuracy of several percents.

Fast and light reaction products turned out to be a convenient tool for calibration of complex instruments based on semiconductor cilicon detectors, in particular, used for space-physics reseacrh. By means of protons produced during reactions of 3Не++ ions it is succeeded to test instruments consisted of a number of detectors with total thickness up to 8 mm.

Studies of production of radioactive isotops of thallium, astatine, used for medical purposes, cobalt-59 and other elements are caaried by means of ejected beam of 4Не++ ions.

II. Accelerator facility of electrostatic (Van de Graaf) generator (EG-8) is intended for production of positively charged protons, alfa-particlesm nitrogen ions, etc. ejected into experimental hall with energy up to 4 MeV/charge which is the maximum theoretically possible for this facility and the maximum current of I = 10 micro ampere. In practice at this accelerator the maximum energy for the protons achived 3 MeV.

Besides the experiments with positively charged particles (protons and alfa-particles) the accelerator was used for acceleration of the electrons and charged microparticles (macrones or dust particles) in order to study their influence on the spacecrafts' surface.

In 1980s the accelerator was essentially upgraded by DSc. Alexander Almazov, who worked as a Senior Reearcher of the Department of atomic nucleus physics from 1980 till 1985.

After full reconstruction of the electrostatic accelerator under his management it became one of the best faciclities in the USSR, conforming to international standards. In particular, tape station of the accelerator was replaced with induction one designed by Alexander Almazov. A new axially-symmetrical septated acceleration tube was installed, accelerator column was also essentially reconstructed. A new high-reliable resistive high voltage divider also designed by Almazov was isntalled in it. System of beam energy stabilization was designed and manufactured.

Currently the accelerator is actively used for the studies of metallic, semiconductor and dielectric materials in poly- and monocrystal phases by means of ion-beam analysis.

III. An accelerator KG-500 is a high-voltage Cockroft-Walton cascade generator with air isolation which is intended for acceleration of positively charges ions in electrostatic field.

Basic parameters of ions acceleration (for hydrogen) are the following:
a) maximum energy - 500 keV;
b) energy stability - 0,1%;
c) energy range - 50-500 keV;
d) direct beam current (at the input of magnetic analyzer) - 1 mA;
e) direct beam current density - 25 mA/mm2;
f) monoatomic ions current in a beam, deflected for 90o, - 0,2 mA.

Vertically directed ion beam is turned in horizontal plane by two magnetic analyzers and ejected for operation in five vacuum experimental chambers and plant MEIS (Medium Energy Ion Scattering) with native energy resolution of ~ 10-3 E0 .

IV. Horizontal electrostatic van de Graaf accelerator (AN-2500) with maximum potentials difference of 2,5 MV manufactured by HVEE (Netherlands) was put into operation in 2009. The accelerator was purchased basing on the Agreement between the Center of Material Science of Gronningen province (Netherlands) and SINP MSU as gratuitous transfer for scientific research and educational purposes.

Technical parameters of the accelerator are the following:
- energy of accelerated particles - up to 2,5 MeV (during the recent years of the acelerator's operation in Gronningen it did not exceed 1,5 MeV);
- types of accelerated particles: positive ions of hydrogen and helium;
- accelrating tube and conductor are situated in a horizontal steel boiler 3 meters in length and 1,5 m in diameter under pressure of 20 atm. of isolating gas.

Accelerator's design provides absence of negative influence to the environment due to radiation monitoring and protection, electromagnetic shielding, зкotection from line noise.