A regular monodisperse flow of spherical microtargets of solid hydrogen or deuterium with a variable diameter of several tens of micrometers and a frequency from several tens to several hundreds of kilohertz is in demand as internal targets in physical experiments at accelerators. The paper is devoted to the modification and launching of a prototype cryogenic corpuscular hydrogen target in which the gas entering the facility is transformed into a flow of spherical microtargets. Processes of cryogenic cooling and liquefaction of the gas, formation of a liquid microjet, and its controlled monodisperse disintegration into equal-sized drops are realized in the target, and they are followed by freezing of the drops and formation of microtargets upon injection into vacuum. The target prototype is composed of the cryogenic, vacuum, and gas systems as well as the systems for control and optical diagnostics of microtarget parameters. The modified target prototype provided monodisperse regimes of generation of microtargets with a diameter of 20–50 μm at a generation frequency of 260–465 kHz.

An electromagnetic scintillation calorimeter using liquid krypton or xenon as the working medium has been built. The calorimeter consists of 45 tapered light-collecting cells with dimensions of (2.1 x 2.1) x 40 x (4.15 x 4.15) cm made from aluminum-coated mylar film 50 mum thick. The light from each cell is detected by photomultipliers. The calorimeter filled with liquid krypton was exposed to a beam of secondary particles with a momentum of 400 MeV/c from the ITEP accelerator. The results of the first test are given.

A scintillating LXe/LKr electromagnetic calorimeter has been built at the ITEP and tested at the BATES (MIT) accelerator. The detector consists of PMT matrix and 45 light collecting cells made of aluminized 50 microns Mylar partially covered with p-terphenyle as a wavelength-shifter (WLS). Each pyramidal cell has (2.1/spl times/2.1)/spl times/40/spl times/(4.15/spl times/4.15) cm dimensions and is viewed by FEU-85 glass-window photomultiplier. The detector has been exposed at 106-348 MeV electron beam. The energy resolution /spl sigma//sub E//E/spl cong/5%//spl radic/E at 100-350 MeV range in LXe, the coordinate resolution /spl sigma//sub x//spl cong/0.7, the time resolution /spl sigma//sub t//spl cong/0.6 ns for single cell have been obtained. Possible ways to improve energy resolution are discussed.<>

We describe the method and report the results of measurements of the cross sections for interaction of antiprotons with nuclei of C, Al, Ti, and Cd at antiproton momenta 1.45 and 1.8 GeV/c. We also report cross sections for interaction of protons with the same nuclei at momenta 1.52 and 1.8 GeV/c. Part of the data on the interaction of protons were used to check the method of measurements, and part are new. The results are satisfactorily described by means of the Glauber multiple scattering theory.

It is suggested that in equations usually used to calculate curves of theoretical distributions of PSP amplitudes in the course of quantum analysis the effect of variations in the quantum values themselves is overestimated and variations in noise level are not taken into account. An equation allowing for both these parameters is suggested. Statistical analysis of "elementary" PSPs of the parietal ganglion ofHelix pomatia and of "minimal" PSPs of hippocampal neurons showed the necessity of allowing for noise variations. By means of the suggested equation theoretical distributions agreeing better with the experimental according to thex2 criterion can be found and variation in the quantum itself can also be determined indirectly.

It is suggested that formulas commonly used to calculate theoretical amplitude distributions of postsynaptic potentials (PSPs) for their further quantum analysis lead to the overestimation of the quantum value variations (sigma nu) and neglect the variations of a noise level (sigma 2n). A proper formula taking into account both parameters in proposed. The necessity to consider sigma 2n is shown by statistical analysis of "individual" and "minimal" PSPs recorded in the neurons of the central ganglion of the snail and hippocampal neurons of the rabbit. Taking into account sigma 2n resulted in a better agreement between theoretical and experimental distributions and provided an indirect method for sigma nu estimation.