New complex EAS installation of the Tien Shan mountain cosmic ray station

Abstract

In this paper we present a description of the new complex installation for the study of extensive air showers which was created at the Tien Shan mountain cosmic ray station, as well as the results of the test measurements made there in 2014-2016. At present, the system for registration of electromagnetic shower component consists of ∼100 detector points built on the basis of plastic scintillator plates with the sensitive area of 0.25m 2 and 1m 2 , spread equidistantly over ∼10 4 m 2 space. The dynamic range of scintillation amplitude measurements is currently about (3 − 7) · 10 4 , and there is a prospect of it being extended up to ∼10 6 . The direction of shower arrival is defined by signal delays from a number of the scintillators placed cross-wise at the periphery of the detector system. For the investigation of nuclear active shower components there was created a multi-tier 55m 2 ionization-neutron calorimeter with a sum absorber thickness of ∼1000g/cm 2 , typical spatial resolution of the order of 10cm, and dynamic range of ionization measurement channel about ∼10 5 . Also, the use of saturation-free neutron detectors is anticipated for registration of the high-and lowenergy hadron components in the region of shower core. A complex of underground detectors is designed for the study of muonic and penetrative nuclear-active components of the shower.The full stack of data acquisition, detector calibration, and shower parameters restoration procedures are now completed, and the newly obtained shower size spectrum and lateral distribution of shower particles occur in agreement with conventional data. Future studies in the field of 10 14 − 10 17 eV cosmic ray physics to be held at the new shower installation are discussed.

Measurements of the low-energy neutron and gamma ray accompaniment of extensive air showers in the knee region of primary cosmic ray spectrum

“…As it is shown in Figure 1, the central part of this installation is an array of 72 scintillation charged particles detectors spread over a rectangular 30×30 m 2 "carpet" area, with the steps between neighbouring points being of 3 m and 4 m along two orthogonal directions. Such a rather dense detector disposition in the region close to the installation center was selected to investigate as precisely as possible spatial distribution of the flow of charged particles within the EAS cores [36]. At the time of the considered experiment 8 additional detectors (P1-P8 in Figure 1) were spread nearly circumferentially around this "carpet" at distances of about 50 − 70 m from its center for the detection of particles at the EAS periphery.…”

“…Since the year 2015, the EAS particles detector system of the Tien Shan mountain station was put once again into operation state after its prolonged modernization period, and regular registration of the neutron component of extensive air showers was resumed here at modern level of the experimental technique [35]. The basic goals of the present Tien Shan cosmic ray experiment were listed in the program article [36]; in particular, it was stated there that application of the various kinds of neutron detectors together with their specific data collection procedure gives a unique possibility to register the response of a single experimental installation to hadronic interactions in an exceptionally wide range of energy deposits, starting from the thermal neutrons, and up to a few TeV order energies of the cosmic ray hadrons. This is especially important for the detection of intensive radiation flows in the central region of powerful air showers.…”

The STM32 microcontroller based pulse intensity registration system for the neutron monitor

“…It should be noted that the use of a compact microprocessor technique with serial communication through a USB interface line and low power consumption allows the creation of portable data registration set-ups for various mobile autonomous detector systems (such as the distant EAS particle detectors [14], remote sensors of the optic and gamma-ray radiation from thunderclouds [15], seismological stations [16], and the like), which are supposed to be used widely at the Tien Shan cosmic ray detector complex.…”

Modern status of the Tien-Shan cosmic ray station

“…To investigate the nuclear active shower components a multi-tier 55 m 2 ionization-neutron calorimeter with a total absorber thickness of ∼ 1000 g/cm 2 , a typical spatial resolution of the order of 10 cm, and dynamic range of ionization measurement channel about ∼ 10 5 was created. In addition, the use of saturation-free neutron detectors is anticipated for registration of the high-and low-energy hadron components in the region of the shower core.…”

“…The average atmosphere depth at the height of the station location is 690 g/cm 2 . At the station a multifunction complex for investigating the various components of extensive air showers has been created [1,2]. The new complex aims to investigate the following fundamental problems in astroparticle and atmospheric physics:…”