Thermal Neutrons in Eas: A New Dimension in Eas Study

A new method to study Extensive Air Shower (EAS) hadronic component is proposed. It is shown that addition of specific detectors for thermal neutron detection to a standard array for EAS study can significantly improve its performance. Results of CORSIKA based Monte Carlo simulations as well as preliminary experimental data are presented. A proposal of novel type of EAS array is given.Comment: 6 pages, 4 figures, a talk given at ISVHECRI2007, Weihai, China. To be published in Nucl. Phys. B (Proc. Suppl.

Lateral Distribution for Aligned Events in Muon Groups Deep Underground

The paper concerns the so-called aligned events observed in cosmic rays. The phenomenon of the alignment of the most energetic subcores of gamma-ray--hadron ($\gamma-h$) families (particles of the highest energies in the central EAS core) was firstly found in the "Pamir" emulsion chamber experiment and related to a coplanar particle production at $E_0>10^{16}$ eV. Here a separation distribution (distances between pairs of muons) for aligned events has been analyzed throughout muon groups measured by Baksan Underground Scintillation Telescope (BUST) for threshold energies $0.85 \div 3.2$ TeV during a period of 7.7 years. Only muon groups of multiplicity $m\geq 4$ with inclined trajectories for an interval of zenith angles $50^\circ - 60^\circ$ were selected for the analysis. The analysis has revealed that the distribution complies with the exponential law. Meanwhile the distributions become steeper with the increase of threshold energy. There has been no difference between the lateral distribution of all the groups and the distribution of the aligned groups.Comment: 4 pages, 3 figures. Prepared for the ISVHECRI'2006, Weihai, Chin

Seasonal thermal neutron flux variations at high altitude

The PRISMA project developed for cosmic ray study above 30 TeV is now realized as 2 prototypes at different altitudes. Special en-detectors are used for both electron and neutron components recording. An array of 4 such detectors is running in Yang Ba Jing (Tibet, China) at altitude 4300 m a. s. l. since January 2013. To be sure that thermal neutron background is stable we also study its variations. Here we present the results of this study, namely seasonal thermal neutron flux variations at high altitude

The array for investigations of EAS neutron component

The neutron component of EAS has not been practically studied for many years. Creation of the neutron detector arrays PRISMA-32 and PRISMA-YBJ demonstrated the effectiveness of such investigations. It is important to underline that recording the EAS neutron component is carried out over the whole array area. Development of a new larger scale neutron detector array (URAN) in MEPhI will continue these studies. During the construction of the URAN array, a new design of en-detectors based on the scintillator with natural boron and new electronics was developed. The use of new electronics with a switchable sampling rate allows one to reach EAS fast timing accuracy up to 10 ns. The en-detectors of the URAN are located on the roofs of the buildings. The sensitive area of each detector is 0.36 m2, while the array's starting area is ∼ 103 m2. Total number of the initial array detectors is 72. They are subdivided into 6 independent clusters each of 12 en-detectors, connected with the central data acquisition station

The array for investigations of EAS neutron component

The neutron component of EAS has not been practically studied for many years. Creation of the neutron detector arrays PRISMA-32 and PRISMA-YBJ demonstrated the effectiveness of such investigations. It is important to underline that recording the EAS neutron component is carried out over the whole array area. Development of a new larger scale neutron detector array (URAN) in MEPhI will continue these studies. During the construction of the URAN array, a new design of en-detectors based on the scintillator with natural boron and new electronics was developed. The use of new electronics with a switchable sampling rate allows one to reach EAS fast timing accuracy up to 10 ns. The en-detectors of the URAN are located on the roofs of the buildings. The sensitive area of each detector is 0.36 m2, while the array's starting area is ∼ 103 m2. Total number of the initial array detectors is 72. They are subdivided into 6 independent clusters each of 12 en-detectors, connected with the central data acquisition station

The array for investigations of EAS neutron component

The neutron component of EAS has not been practically studied for many years. Creation of the neutron detector arrays PRISMA-32 and PRISMA-YBJ demonstrated the effectiveness of such investigations. It is important to underline that recording the EAS neutron component is carried out over the whole array area. Development of a new larger scale neutron detector array (URAN) in MEPhI will continue these studies. During the construction of the URAN array, a new design of en-detectors based on the scintillator with natural boron and new electronics was developed. The use of new electronics with a switchable sampling rate allows one to reach EAS fast timing accuracy up to 10 ns. The en-detectors of the URAN are located on the roofs of the buildings. The sensitive area of each detector is 0.36 m2, while the array's starting area is ∼ 103 m2. Total number of the initial array detectors is 72. They are subdivided into 6 independent clusters each of 12 en-detectors, connected with the central data acquisition station