V. V. Ashikhmin

Measurement of neutron number generated by cosmic-ray muons in iron using the LVD

The experiment to measure the neutrons numbers generated by muons in iron (Fe) and lead (Pb) carried out using LVD. A full Monte Carlo simulation of the actual geometric configuration of the experiment is performed. The first measurement results are obtained. The measured yield of neutrons produced by muons with an energy of 280 GeV in iron is 16 × 10−4 n/μ/(g cm−2).

LVD Experiment: 25 Years of Operation

The current status of the LVD (large volume detector) experiment aimed at search for neutrinos from the gravitational collapse of stellar cores is described. Within the period of observations from June 1992 to February 2017, no gravitational collapse was found in the Milky Way Galaxy and Magellanic Clouds, including hidden ones (not ejecting the envelope). The LVD collects data for 99% of the live time. A limit on the frequency of supernova bursts within a distance of 25 kpc was set at a level of 0.1 event/yr. The most recent results obtained by studying the muon component of cosmic rays are presented.

Search for Neutrino Bursts from Collapsing Stars by Means of the LVD and BUST Detectors

A long-term and stable operation of the LVD and BUST detectors in searches for neutrino bursts from gravitational star collapses is demonstrated, and a random origin of background pulses in the detectors is confirmed thereby. The experimental results obtained by means of the LSD and BUST detectors on February 23, 1987, are considered in detail. The probability for the possible backgroundmimicked coincidences of clusters of pulses recorded in the LSD detector at 2 : 52 UT with a group of correlations of pulses within 1 s between LSD and BUST in the interval from 1 : 45 to 3 : 45 UT is estimated. Also, coincidences of the background pulses in the LVD and BUST detectors over the period of about eight years are analyzed. The results obtained in this way give sufficient grounds to conclude that the cluster of pulses recorded by the LSD detector on February 23, 1987, at 2 : 52 UT and the coincidences of individual pulses in the LSD and BUST detectors are events associated with the gravitational collapse of SN 1987A.

Seasonal variations in the muon-induced neutron flux and background of natural radioactivity at the Gran Sasso Underground Laboratory

Cosmic ray muons at average energies of 280 GeV and muon-induced neutrons are detected by the LVD (Large Volume Detector). An analysis of seasonal variations in the neutron flux, based on data collected over 15 years, is presented. Measuring of the seasonal variations in the specific number of neutrons generated by muons allows us to determine the magnitude of variations in the average energy of the muon flux at the depth of the LVD’s location. The source of the seasonal variations in the total neutron flux is a change in the intensity and average energy of the muon flux. An analysis of the long-term monitoring of the LVD’s low-energy background is also presented.

Joint analysis of experimental data to search for neutrinos from collapsing stars using the LVD and BUST apparata

Preliminary results of the search for neutrino bursts from collapsing stars using the experimental data of two detectors, the INR’s Baksan Underground Scintillation Telescope (BUST) and the Gran Sasso Large Volume Detector (LVD), are presented. The frequency of coincidence of single pulses measured by these detectors made on the bases of the same liquid scintillator is studied using experimental data obtained in 2012. The results can be explained by random pulse coincidences in the LVD and BUST detectors.

Generation of neutrons produced by muons from CERN neutrino beam

Preliminary results of neutron generation by muons, produced in CERN neutrino beam with average energy 17 GeV in LVD experiment are presented for the period 2008–2011 yrs. A Monte Carlo simulation of neutrons produced by horizontal muons was performed using the Geant4 software package. The efficiency of neutron detection in the LVD was calculated. For iron-based and white spirit scintillators, the measured neutron yields prove to be Ysc = (3.6 ± 0.7) × 10−5n/μ (g−1 cm2) and YFe = (23.2 ± 4.6) × 10−5n/μ (g−1 cm2).

Neutrons produced by muons in LVD: Monte Carlo simulation

The results of Monte-Carlo simulations of neutron production by muons in LVD obtained with Geant4 and SHIELD programs are presented. The detection efficiencies of gammas and neutons in the LVD are calculated.

Study of neutron interactions with NaCl in LVD

LVD detector, located in Gran Sasso National Laboratory, has been working on the program of the search for neutrino radiation from gravitational collapses of stars since 1992. In 2005 additional modifications of the detector by adding NaCl target were made. For the last two years the experiment with one portatank (8 counters) of LVD has been under way. Monte-Carlo simulation and its comparison with experimental data are presented and discussed in this paper.

Search for neutrino radiation from collapsing stars with the Artyomovsk scintillation detector

The current status of an experiment designed to search for neutrino radiation from collapsing stars using the Artyomovsk Liquid Scintillation Detector is described. Observations were conducted from November 1977 to July 2012. The upper limit for the mean rate at which neutrino bursts occur in the Galaxy is found to be fcol < 0.0658 events per year at a 90% confidence level. In 35 years of observations, no supernovae were detected in the Galaxy.

Neutrons produced by muons in the LVD matter

The calculation results on the production, transport, and capture of neutrons produced by muons passing through the LVD are presented. The calculations are performed using the Monte Carlo transport codes GEANT4 and SHIELD. The efficiency of detecting the neutrons produced in both the scintillator and the detector’s structure is determined.