Effective exploitation of a geyser bubble-chamber equipment as a background-free fast neutron detector

The MOSCAB equipment, a geyser-concept bubble-chamber originally thought for the search of dark matter in the form of WIMPs, is employed for the detection of fast neutrons. Once the background-free operating conditions are determined such that the detector is sensitive only to neutrons, which occurs when the neutron energy threshold required for nucleation is higher than approximately 2.5 MeV, the detector response to fast neutrons is investigated using a $${^{241}}$$ 241 AmBe neutron source. Sets of detection efficiency functions are then produced via Monte Carlo simulations and post-processing, their validation being performed experimentally and discussed. Finally, the use of the detector to measure the fast neutron activity of very weak n-sources in low neutron background environments, as well as to monitor the cosmic ray variations through the neutron component of the Extensive Air Showers, is considered.

The Stability and Elasticity in Ta-Ti-V Medium-Entropy Alloys Using First-Principles Calculations

Due to the low neutron activity, the high thermal stability, and the good compression strength at elevated temperatures, medium-entropy Ta-Ti-V alloys have the application potential to be used in future nuclear engineering. According to experimental results, a special quasi-random structure (SQS) model and first-principles calculations are used to calculate the structural stability and the elasticity of the ternary single-phase body-centered cubic (BCC) Ta-Ti-V alloys with the compositions Ta24Ti14V16, Ta19Ti17V18, Ta16Ti21V17, Ta22Ti23V9, and Ta18Ti18V18. The mixing energy of five compositions is positive, which indicates that they are unstable at low temperature but stable at high temperature. Meanwhile, we predict the ability of elasticity in those five compositions, and the sequence of bulk modulus is Ta24Ti14V16 > Ta19Ti17V18 > Ta18Ti18V18 > Ta16Ti21V17 > Ta22Ti23V9 and ductility is Ta19Ti17V18 > Ta18Ti18V18 > Ta22Ti23V9 > Ta24Ti14V16 > Ta16Ti21V17. Additionally, the influence of the element content on elastic properties shows that the Ta content will increase the bulk modulus of the alloys, while Ti content decreases the bulk modulus. Higher V and Ti contents are beneficial to ductility, especially the V content. The higher Ta content will sharply reduce the ductility of the alloys. Our calculation has provided further theoretical mechanism for the Ta-Ti-V medium-entropy alloys (MEAs) preparation and development.

Space weather and human deaths distribution: 25 years’ observation (Lithuania, 1989–2013)

Human health is affected by space weather component [solar (SA), geomagnetic (GMA), cosmic ray (CRA) – neutrons, space proton flux] activity levels. The aim of this study was to check possible links between timing of human (both genders) monthly deaths distribution and space weather activity.Human deaths distribution in the Republic of Lithuania from 1989 to 2013 (25 years, i.e., 300 consecutive months) was studied, which included 1,050,503 deaths (549,764 male, 500,739 female). Pearson correlation coefficients (Space factors were interrelated as follows for the considered period: CRA was inversely related to SA and GMA, CRA/SA (Most groups of deaths are related to space weather component activity. Extreme levels of activities of both groups (SA, GMA, and opposite CRA – neutron) are related to some health risks. In the considered period, there were relatively few GMA storms and low GMA was dominating, accompanied by higher CRA (neutron) activity. The ways of action of the components of space weather on the human body need additional studies. There is a special need for the prevention of rising cerebral vascular accidents and oncology malignancies as the causes of death.

Considering space weather forces interaction on human health: the equilibrium paradigm in clinical cosmobiology – is it equal?

We are constantly affected by changes in space weather. The principal “players” are solar activity (SA), geomagnetic activity (GMA) and antagonistic to them, cosmic ray activity (CRA) and high energy proton flux. CRA is measured by neutron activity on the earth’s surface in imp/min. SA and GMA are linked and serve as a shield for the earth from CRA. For a long time SA and GMA were the main areas of studies. The aim of this study was to compare some effects of the mentioned forces and discuss the temporal distribution of both groups of space weather, in relation to their effects on humans.The time distribution of GMA storms (daily) was compared with quiet (low) GMA, with higher CRA (neutron activity). Space weather data were obtained from the USA, Russia and Finland.A total of 4383 days were analyzed in the years 2000–2012. A total of 71 days (1.62%) of geomagnetic storms (GS) and 2753 days (63.8%) of quiet (IDespite a great number of publications and the significant role of GS, it is a relatively rare event and most medical emergencies and deaths occur on days of low GMA, accompanied by higher CRA (neutron activity). High neutron activity deserves more attention when analyzing space effects on human health and their mechanism of action.