A.B. Ivanov

A high precision straw tube chamber with cathode readout

Abstract The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm diameter straws were made of aluminized Mylar with transparent longitudinal window. The X -coordinate information has been taken from cathode strips as induced charges and investigated with the centroid method. The spatial resolution σ x = 103 μ m was obtained at a signal-to-noise ratio of about 70. The possible ways to improve the signal-to-noise ratio are discussed.

Development and application of a multistep chamber for digital radiochromatography imaging

Abstract A device based on multistep chamber has been developed for high-sensitive automation express-analysis of flat radiochromatograms and electrophoregrams. The device operated on-line with an SM-4 computer. The spatial resolution for β detection from 14 C, 35 S and 32 P radionuclides and for X-ray detection from 125 I is not worse than 1 mm. Analyzing the samples, radioactive spots are localized and their relative activity is measured. The time of analyzing the 160×160 mm 2 samples is not larger than 30 min. The device possesses high stability and the reproducibility of measurement results.

Automatized One-dimensional X-Ray-Detector

One-dimensional gas-filled X-ray detectors with delay line readout have been developed and tested on line with IBM-PC. The pressure of a xenon (90) and CH4 (10) mixture can be set over a range of 1–10 atm. The position resolution for 8 keV photons is about 170 μm. Main properties and possible applications of the detector are presented.

Relativistic hypernuclei at Dubna

At the Laboratory of High Energies (JINR, Dubna) a unique approach was elaborated with hypernuclei produced by the excitation of the beam nuclei and their decays observed at a distance of tens of cm behind the production target. While the very first experiments were carried out in the Synchrophasotron beams, more extensive hypernuclei research programme is planned for the Nuclotron accelerator and the new spectrometer created by the authors. At the time of the conference the first test run in the Nuclotron beam was in progress. Investigation of hydrogen hypernuclei isotopes is in the first line of the experimental research plans. Namely, lifetimes and production cross sections of Λ 4 H and Λ 3 H will be measured. Search for Λ 6 H is also among the tasks.

Development and investigation of a neutron radiography imaging system with a low-pressure multistep chamber

An imaging system of thermal neutrons for an investigation of digital neutron radiography has been developed and tested. Some characteristics obtained on a neutron radiography beam of an experimental reactor are reported. The coordinates of each event are determined in this system. After processing in a LSI 1123 computer, a radiograph, accumulated in a histogramming memory of 64 K 16-bit words, is presented on a colour display. A 230 × 180 mm2 low-pressure multistep chamber is used as a detector. Neutron conversion takes place in a 6 μm boron layer enriched to 86% in 10B. The detection efficiency of thermal neutrons is no less than 3%. The count rate of the system reaches up to 2 × 105 events per second. A radiograph can be obtained within 10 minutes. The sensitivity of this system to gamma-background is low. One event/s is detected for a background of 1 R/h. The spatial resolution is found to be 0.7 mm (FWHM) using a cadmium knife edge. The integral nonlinearity is less than 0.4%. The possibility of using a hydrogeneous converter in this system for neutron radiography is discussed.

The development and utilization of multiwire coordinate detectors for an express-analysis of labelled compounds in thin layer chromatography

Abstract Characteristics of multiwire position sensitive chambers for an express-analysis of labelled compounds in thin layer chromatography are described. The analysis is characterized by a relatively high detection sensitivity, good data reproducibility and high spatial resolution.

A high resolution gamma camera based on a multiwire position-sensitive detector

Abstract Information is presented on parameters of a gamma camera for γ-ray detection over a range of 50–100 keV. A multiwire proportional chamber used as a detector is filled with a 90% xenon-10% methane mixture at a pressure of 5 atm. The data are read out by means of electromagnetic delay lines. The efficiency of the detector for this energy range is 25–40%. The intrinsic spatial resolution is no worse than 1.5 mm for 60 keV photons and the central field of view. The sensitive area is 270 × 270 mm 2 , the central field of view 240 × 240 mm 2 . Results of testing the gamma camera are presented. The work has been performed at the High Energy Laboratory, JINR.

Formation of an intense electron beam in guns with a small-diameter cathode

In the given work the experimental results of formation of the electron beam with a current up to 4 A in the electron gun with the cathode of a small diameter - 13 mm are presented. The gun is intended for generation of intense electron beams in systems of electron cooling used for fast and deep cooling of ions in the scheme with large factor of expansion in a decreasing magnetic field.

New developments and investigations of PSD at JINR, LHE

Abstract The main parameters and test results of several position-sensitive detectors for investigations by means of soft X-rays, slow neutrons and ions are presented.

Recent progress in developments and applications of imaging detectors at LHE, JINR

Abstract Data on the development and investigation of position-sensitive detectors performed at the Laboratory of High Energies, JINR for X-ray structural studies and in beta autoradiography are presented. The parameters of the position-sensitive detectors of thermal neutrons with a high-pressure multiwire proportional chamber and a low-pressure multistep chamber are described. The characteristics of the imaging detector with a CCD matrix which is being developed are discussed.