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[en] The accelerator facilities at Gatchina which are used both for basic physics purposes and for investigation of the radiation effects are described. The 1 GeV synchrocyclotron is a basic accelerator facility at Gatchina. The proton energy is fixed and equals 1 GeV, the extracted beam intensity can be varied from 10⁶ up to 6.10¹² l/s. The long burst operation system provides variation of the beam macro pulse duration from 300 μs up to 10 ms. A meson-production target installed in the accelerator hall is used through 3 meson channels that can operate simultaneously. The neutron generator (NG) is another facility at Gatchina. The yield of 14 MeV neutrons if up to 2.10¹² /s and the irradiation facility allows a neutron flux up to 10¹¹ n.cm^-2.s^-1 on the irradiated sample. The electrostatic accelerator (ESA) accelerates protons, deuterons and electrons in the range of 0,3 - 1,8 MeV. The intensity of the ion beam is from 1 nA up to 30 μA. (A.C.)

[en] The Data Center is a part of the Nuclear Spectroscopy Laboratory in the Neutron Research Department of the Petersburg Nuclear Physics Institute. It consists of five physicists, one mathematician and one programmer. Main directions of the Data Center activity: Nuclear data evaluation (vertical evaluation); Analysis of large sets of nuclear data (search and correction of errors); Improvement of evaluation tools (new algorithms and codes); Systematics of nuclear data (horizontal evaluation); Search for new regularities in nuclear data

[en] The Data Centre is part of the Nuclear Spectroscopy Laboratory in the Neutron Research Department of the Petersburg Nuclear Physics Institute (PNPI), and covers the work of three physicists and one mathematician. Our main activity is connected with information support of fundamental research nuclear reactor technologies, and the evaluation of nuclear data for nuclear spectroscopy.

[en] The article reports on achievements of various people, staff changes and position opportunities within the CERN organization and contains news updates on upcoming or past events. The main decisions taken at the eleventh meeting of the International Committee for Future Accelerators (ICFA) - held last October at the Leningrad Institute of Nuclear Physics, Gatchina - concerned the setting up of the four international panels which were proposed and agreed at the ICFA Seminar held at the Japanese KEK Laboratory earlier in the year. On 14 January the last of the 48 bending magnets of DESY-II, the new 9 GeV injection synchrotron for electrons and positrons, was installed in the tunnel of the 20 year-old DESY synchrotron in Hamburg. An international history symposium on 'Particle Physics in the 1950s: pions to quarks,' will be held at Fermilab in Batavia, Illinois on 1-4 May 1985

[en] We propose an experiment on search for neutron–antineutron oscillations based on the storage of ultracold neutrons (UCN) in a material trap. The sensitivity of the experiment mostly depends on the trap size and the amount of UCN in it. In Petersburg Nuclear Physics Institute (PNPI) a high-intensity UCN source is projected at the WWR-M reactor, which must provide UCN density 2-3 orders of magnitude higher than existing sources. The results of simulations of the designed experimental scheme show that the sensitivity can be increased by ∼ 10–40 times compared to sensitivity of previous experiment depending on the model of neutron reflection from walls. (paper)

[en] The methods and instruments of dynamic laser goniometry developed over many years of research carried out in the St Petersburg State Electrotechnical University [formerly Leningrad Electrotechnical Institute (LETI)] are considered. The primary sources of error and conditions for error minimisation are identified and evaluated. The laser goniometers developed have been used to certify optical polygons and angular position sensors, to estimate angular motion parameters of various objects, and specifically to measure angular positions of crystals in the unique diffraction spectrometer built at the St Petersburg Institute of Nuclear Physics (PINP) of the Russian Academy of Sciences. Modern measurement technologies combined with a self-calibrated ring laser allowed a large amount of measuring information to be accumulated over a short (1 to 5 min) period of time and ensured that the random component of angle measurement uncertainty is as small as 0.02 to 0.03 in the 0 - 360⁰ range. On the basis of inertial properties of a ring laser, a new concept was proposed for constructing a new generation of measuring systems intended to estimate complex angular motions and to provide dynamic calibration of multiple-axis test beds, large-scale antenna systems, telescopes, and other objects. (laser gyroscopes)

[en] In-source laser spectroscopy experiments for bismuth isotopes at the 306.77 nm atomic transition has been carried out at the IRIS (Investigation of Radioactive Isotopes at Synchrocyclotron) facility of Petersburg Nuclear Physics Institute. New data on isotope shifts for ^{189–198,211}Bi isotopes and isomers have been obtained. The changes in the mean-square charge radii were deduced. The large isomer shift has been observed for the intruder isomer states of Bi with spin I = 1/2 (A = 193, 195, 197). This testifies to the shape coexistence in these nuclei with the intruder isomer states more deformed than the ground states. Marked deviation from the nearly spherical behavior for ground states of the even-neutron Bi isotopes at N < 109 is demonstrated, in contrast to the Pb and Tl isotopic chains.

[en] Results of calculations of energy releases and temperature fields in the ultracold neutron source under design at the WWR-M reactor are presented. It is shown that, with the reactor power of 18 MW, the power of energy release in the 40-L volume of the source with superfluid helium will amount to 28.5 W, while 356 W will be released in a liquid-deuterium premoderator. The lead shield between the reactor core and the source reduces the radiative heat release by an order of magnitude. A thermal power of 22 kW is released in it, which is removed by passage of water. The distribution of temperatures in all components of the vacuum structure is presented, and the temperature does not exceed 100°C at full reactor power. The calculations performed make it possible to go to design of the source.

[en] Recent measurements of the neutron lifetime performed using a gravitational trap of ultracold neutrons (UCNs) (Konstantinov Petersburg Nuclear Physics Institute, Russia) and a magnetic UCN trap (LANL, USA) have confirmed PNPI’s result of 2005. The results of experiments with stored UCNs agree with each other but differ from those of the beam experiment (NIST, USA) by 3.5σ (corresponding to 1% in the decay probability). This disagreement is currently being discussed in the literature as a ‘neutron anomaly’. We analyze possible reasons for that disagreement and test the experimental data for the neutron lifetime and beta-decay asymmetry within the Standard Model. The test is only passed for neutron lifetime values that are obtained using the UCN storage method. (physics of our days)