UKP-2-1 Accelerator complex

The accelerator UKP-2-1 includes two independent beam transportation channels, united by one accelerating potential. The Cockcroft-Walton cascade generator provides accelerating voltage up to 1 MV. One of the channels is designed to accelerate hydrogen ions and inert gases produced from a duoplasmatron with a displaced emission hole. The second channel includes a source with cesium sputtering and is designed to accelerate heavy ions. Turbomolecular and magnetic discharge pumps used to pump out the ducts provide a vacuum of 2.3×10^-7 Torr in the channels. The transportation channels include doublets of electrostatic quadrupole lenses controlled by high-voltage units from a computer. The heavy ion injector magnet and bending magnets provide preliminary separation of the heavy ion beam and transportation of accelerated beams to the target chambers. Analyzing magnets, including magnetic field stabilization by nuclear magnetic resonance, have a mass resolution of DM/M=250.

In 2001, a new 40-position heavy-ion source MS-SNICS, manufactured by National Electrostatic Corporation (USA), was purchased and put into operation. Thus, it became possible to quickly, without breaking the vacuum, change the cathode of the source, thus resetting the channel to a new type of ion. This is especially important for some analytical applications developed at the accelerator.

The technical capabilities of UKP-2-1 make it possible to obtain accelerated beams of ions from hydrogen to plutonium with energies in the range from 300 keV to 4 MeV and beam currents on the target from a few nanoamps to tens of microamps. As a result of technical improvements, an energy spread in the proton beam of ~100 eV was achieved at an ion energy of 1 MeV [2 – 5].

Heavy ion source MS-SNICS from NEC

Technical characteristics of the beams

During operation of the accelerator, a system for auto information collecting and controlling accelerator parameters was developed to ensure the reliability and long-term stability of the resulting beams. The system is based on the conversion of analog signals from the lower arm of the cascade generator divider, from Hall sensors of magnetic analyzers, electrostatic lenses and an electrostatic analyzer into a digital code. Subsequently, the converted signals are compared with the setting parameters set by the operator, and the error signal is fed through a digital-to-analog converter (DAC) to the power system of the corresponding accelerator device, adjusting its operating parameters to the required values. In addition, the beam current on one of the Faraday cups of the beam transportation system is controlled through the DAC. The information collection and processing system is controlled using a personal computer IBM PC. The control program is written in the National Instruments Labview development environment.

In 1995, the staff of the accelerator facility jointly with the Institute of Theoretical and Experimental Physics (Moscow, Russia) and GSI (Darmstadt, Germany) carried out measurements of Coulomb energy losses by fast protons in a flame target [6].

In 1998, a proton microprobe system was developed based on the proton beam transport channel, which makes it possible to obtain a beam with a diameter of ~10 μm on a sample. The system included object slits, an electrostatic scanner, and a doublet of short-focus electrostatic lenses [7]. The resulting beam of micron sizes was used within the framework of the ISTC Project K-749 “Study and systematization of “hot” soil particles of SNTS” to obtain the distribution of radionuclides over the volume of “hot” particles, as well as within the framework of the ISTC Project K-472 “Assessment of chemical and radiation loads on the children body in the region of the Aral environmental disaster and the development of a rehabilitation strategy” for the analysis of biological fluids and tissues [8, 9].

Currently, a set of nuclear-physical analysis methods has been developed and widely used at the UKP-2-1 accelerator, including the Rutherford backscattering method, the X-ray analysis method with proton excitation, and the method of resonant nuclear reactions. For these purposes, an additional light ion transportation channel was designed, equipped with a target chamber shown in the figure below. The camera includes a Si(Li) detector for recording X-ray radiation with a resolution of 145 eV (at a line of 5.9 keV), located at an angle of 45º to the normal to the target, a surface barrier detector for recording back-scattered particles with a resolution of 15 keV, located at an angle of 130º to the direction of beam motion and a Na(I) scintillator for γ-quanta recording.

Experimental target chamber

One of the perspective areas being developed at the UKP-2-1 accelerator is the method of accelerator mass spectrometry (AMS). The AMS method is currently one of the most popular tools in the world for the analysis of ultra-low contents of long-lived natural and artificial radioisotopes. The world's leading laboratories specializing in radioecology, dating and astrophysics are trying to develop AMS on their basis, realizing the uniqueness of the results obtained by this method. The problem of analyzing ultra-low concentrations of plutonium and uranium is of particular relevance for Kazakhstan with the Semipalatinsk nuclear test site (SNTS), as well as two dozen uranium mining mines on its territory. Quantitative data on the content of uranium and plutonium isotopes in biological samples of mine’s personnel and residents of the areas adjacent to the SNTS are required to assess the potential impact of radiation dose on human health, low-dose exposure and for validation or development of new and improved dosimetric models. The AMS method will solve this problem. The expected detection limit for ²³⁹Pu in biological samples (urine, blood, etc.) in this case should be 500 nBq/L.

List of publications on the topic “Heavy ion accelerator UKP-2-1”

Golubev V.P., Ivanov A.S., Latmanizova G.M., Modek A.I., Nikiforov S.A., Pikalev A.S., Svinin M.P., Subbotkin S.A., Arzumanov A. .A., Bayadilov E.M., Gorlachev I.D., “UKP-2-1” heavy ion accelerator complex, Proceedings of the XII All-Union Meeting on Charged Particle Accelerators, Moscow, 1990., pp. 139 – 142.

Gorlachev I.D., Lysukhin S.N., “Automatic adjustment system for lenses - correctors of the tandem accelerator UKP 2-1”, Proceedings of the X Meeting on Tandem Accelerators, Obninsk, 1991, pp. 232 - 234.

A.A. Arzumanov, A.N. Borisenko, I.D. Gorlachev, S.N. Lysukhin "Improvements of heavy ion accelerator UKP 2-1" Proceed. of the XIII particle accelerator conference, Dubna, Russia, 13-15 October 1992, v.1, p. 118-121, Moscow.

Arzumanov A.A., Borisenko A.N., Gorlachev I.D., Lysukhin S.N., “Improving the energy characteristics of the tandem accelerator in Alma-Ata”², Proceedings of the XIV Meeting on Charged Particle Accelerators, Dubna, 1994, pp. 65 - 68.

Arzumanov A.A., Borisenko A.N., Gorlachev I.D., Lysukhin S.N., Platov A.V., “Improving the voltage stability of the cascade generator of the UKP-2-1 accelerator,” Proceedings of the XI Meeting on Electrostatic Accelerators, Obninsk, 1995, pp. 222 - 228.

G.Belyaev, M.Basco, A.Cherkasov, A.Golubev, A.Fertman, I.Roudscoy, S.Savin, B.Sharkov, V.Turticov (ITEP, Moscow) A.Arzumanov, A. Borisenko, I. Gorlachev, S. Lysukhin (INP, Alma-Ata) D.H.H. Hoffman, A. Tauschwitz (GSI, Darmstadt) "Measurement of Coulomb energy losses by fast protons in a plasma target" Phys. Rev. E 53, N 3, 2701 (1996).

Arzumanov A.A., Borisenko A.N., Gorlachev I.D., Lysukhin S.N., Platov A.V., ²Features of microbeam formation on a tandem accelerator in Alma-Ata², Proceedings of the XII Meeting on Electrostatic Accelerators, Obninsk, 1997, pp. 81 - 85.

Punin V.T., Abramovich S.N., Buzoverya M.E., Chulkov V.V. (VNIIEF), Gorlachev I.D., Lysukhin S.N. (INP NNC RK), Shabalin V.N., Shatokhina S.N. (RNIIG RF), ^“Elemental analysis of biofluids using proton microprobing”, Proceedings of the 2nd International Conference on Nuclear and Radiation Physics, Almaty, 1999, pp. 226-236.

I. Gorlachev, R. Isaeva, B. Knjazev, Z. Mazhitova, A. Platov‚ V. Zaichik, Use of the nuclear-physical methods at the tandem accelerator for the determination of trace element contents in human lung tissue‚ Proceeding of the XV International Conference on Electrostatic Accelerators and Beam Technologies‚ Obninsk‚ 2003.