[en] Short communication

No abstract available

[en] It is known that the efficiency of a detector epsilon(x) is connected to the escape function P(x) by the relation epsilon(x) = xP(x). In this paper, a specific detector is considered (3'' x 3'' NaI), and the results obtained are compared with previously results. (orig.)

[en] Stopping muons were investigated at a depth of 850 gg/cm^-₂ by means of the Baksan underground scintillation telescope. Mean lifetime of a nuon obtained from the decays recorded constitutes 2.14+-0.14 μs. For muons of atmospheric origin determined was the ratio of the muon quantity stopping in 100 gxcm^-₂ thick layer of a standard ground and the number of muons passing through this layer Rsub(atm)=(2.5+-0.1)x1a^-₃. For locally produced muons Rsub(l.p.)=(0.8+-0.1)x10^-₃. The results obtained agree well enough with theoretical predictions

[en] Edge penetration through a collimator system by radiation emitted from either a point or an extended source is studied, using the small angle approximation. Extremely accurate formulas are drived for calculating the penetration fluence. We find that the ratio of the penetrated fluence to the unimpeded fluence has a remarkably simple form; its leading term is independent of both the length and the radius of the collimator. Furthermore, the same results are applicable to a point source as well as an extended source, for a wide class of aperture shapes the collimator may take. We have also derived the formulas to computed the edge penetration at the near end of the collimator, which occurs when the distance from the source to the collimator axis exceeds the collimator radius. The accuracy of our results has been checked by Monte Carlo calculations for both neutron and gamma-ray radiations. We found excellent agreement between the analytical and numerical results. (orig.)

[en] The absolute intensity of vertical cosmic ray muons at sea level with momentum above 0.32 - 1.78 GeV/c at a geomagnetic latitude 25.5⁰N have been carefully measured by means of a narrow angle proportional counter telescope, which can distinguish a passage of penetrating muon. The present spectrum after being corrected scattering, proton contribution and geomagnetic latitude effect, has been compared with the some other spectrum. Our results are in good agreement with Allkofer et al's result. The differential and integral intensity have been found to be (7.30+-0.17)x10^-3/cm² s sr and (3.02+-0.17)x10^-3/cm² s sr (GeV/c), at momentum 1 GeV/c, respectively

No abstract available

[en] Simultaneous observations of fine structure photospheric features at several wavelengths are described. The observations, which include regions near disk center and at the limb, were obtained using a narrow band calcium filter and selected wavelengths in Mg b₁, the red wing of Hα and the Hα continuum using the Universal Birefringent Filter of the Sacramento Peak Observatory. From the disk-center series it is concluded that bright point structures seen in calcium are cospatial with the Hα filigree and are related in origin. The limb photographs confirm that the calcium network is cospatial with the white light faculae. However, in regions of good seeing it is clear that even at the limb the calcium network patterns consist of individual bright points which are essentially the same as those seen near disk center. Thus it is concluded that the white light faculae, the Hα filigree and the calcium bright points are different manifestations of the same photospheric features. (orig.)

[en] Gamma ray burst sources are presumably not larger than 10 to the 9th power cm as inferred from observed flux variations. If they are homogeneous and isotropically radiating, then from photon density considerations, they would have to be optically thick due to gamma-gamma pair production when assumed to be too far away. Deviations of observed photo spectra from an exponential shape around 1 MeV lead to an upper limit of the possible distance of such sources of only 2 kpc from the sun. Thus the sources must be galactic unless the radiation is highly beamed or emerges from a relativistically moving shell. This conclusion depends only on observed parameters. The possible presence of particles and fields in the sources would require them to be even closer

[en] In most locations there are no data on either global or diffuse radiation. Yet most of the existing correlations for predicting the latter require measured data on the former. This is because these correlations express the diffuse radiation as a function of the clearness index. To overcome this, one approach has been to develop correlations of diffuse radiation as a function of sunshine hours. This paper considers another approach: that of using predicted values of global radiation when measured values are not available. With this approach one could then use correlations of diffuse radiation as a function of clearness index. In this paper we have carried out a comparative assessment of the two approaches and reached the conclusion that the latter is more accurate. (author)