The array for EAS neutron component detection

Abstract

The idea of a novel type detector array is the following: delayed thermal neutrons generated by hadronic component of Extensive Air Showers (EAS) can be detected over the whole array area using special electron-neutron detectors (en-detectors). The array PRISMA-32 consists of 32 en-detectors, deployed over the area of 450 m 2 . En-detectors are able to detect two main EAS components: electromagnetic one in a case of a synchronous passage of several charged particles, and hadronic component through thermal neutron captures. Detectors are based on a specialized inorganic scintillator, being a granulated alloy of ZnS(Ag) with LiF, enriched up to 90% with 6 Li isotope. The array is triggered by the electromagnetic component of EAS, and provides information about the energy deposit (mostly electrons) and delayed neutrons accompanying the EAS within 20 ms after the trigger. During 2 years of operation more than 10 5 events were recorded. Examples of EAS detection are presented.

Investigation of the EAS Neutron Component with the PRISMA-32 Array

“…The pulses are integrated with the time constant of 1 µs using a special discriminator-integrator-unit (DIU) of front-end electronics. The first-level trigger is produced by a coincidence of any two of the 16 detectors of the cluster with a threshold of five particles in a time gate of 1 μs [1]. Cluster structure of the PRISMA-32 detector is presented in figure 4.…”

Detection of thermal neutrons with the PRISMA-YBJ array in extensive air showers selected by the ARGO-YBJ experiment

“…On the contrary, the EN-detectors, relatively simple, compact and cheap, can be easily deployed in an air shower array to record simultaneously thermal neutrons and the charged particles in the shower front [22] . A prototype array of 32 ENdetectors (PRISMA-32) is now running in Moscow [37] [38]. In order to check the performance of this detector at a high altitude site, a small array composed of four EN-detectors (PRISMA-YBJ) has been installed inside the hall hosting the ARGO-YBJ experiment at the Yangbajing Cosmic Ray Observatory (Tibet, China, 4300 m a.s.l.…”

Experimental complex for multi-component registration of the EAS in a wide energy range $(10^{15} - 10^{19} eV)$

“…To detect the lateral distribution of thermal neutrons generated by the hadron component of the EAS, around NEVOD, at the level of the upper edge of the water volume, the PRISMA-32 array is deployed [14]. PRISMA-32 detection system consists of 32 en-detectors composed of two 16-detector clusters.…”

“…Time synchronization of clusters with an accuracy of 10 ns is performed using GPS/GLONASS systems. For the registration of the EAS neutron component, a new type of detector, well-proven in the PRISMA-32 setup [14], is used. The scheme of the detector with the outer enclosure is shown in right panel of Fig.…”