Thin-film breakdown counters and their applications (review)

Experimental techniques based on the use of thin-film breakdown counters fabricated at Khlopin Radium Institute are reviewed.     

Modelisation and distribution of neutron flux in radium–beryllium source (<Superscript>226</Superscript>Ra–Be)

Using the Monte Carlo N-Particle code (MCNP-6), to analyze the thermal, epithermal and fast neutron fluxes, of 3 millicuries of radium–beryllium, for determine the qualitative and quantitative of many materials, using method of neutron activation analysis. Radium–beryllium source of neutron is established to practical work and research in nuclear field. The main objective of this work was to enable us harness the profile flux of radium–beryllium irradiation, this theoretical study permits to discuss the design of the optimal irradiation and performance for increased the facility research and education of nuclear physics.     

A novel scheme of optical Meyer wavelet filter based on time lenses in nonlinear multi-span optics fiber communication system

In this work, a novel scheme to realize optical Meyer wavelet filter based on time lenses and Mach–Zehnder modulators in optical domain was proposed and the transfer functions of Meyer wavelet decomposition and reconstruction processed in frequency domain were derived to realize Meyer wavelet de-noising for optical signal. The filter could be used to reduce the nonlinear noise induced by the interaction of EDFA’s ASE noise, fiber’s dispersion and nonlinearity in high bit rate multi-span optical communication systems without photo-electric conversion. The bit error rate curves of the optical bit sequence without and with optical Meyer wavelet filter were plotted to show the effectiveness of the optical Meyer wavelet filter, which can achieve better result and improve the optical communication quality in dispersion compensation links.     

Zur Entdeckungsgeschichte des Radons

The radioactivity of the noble gas radon and its short-life daughter products as the essential part of natural radioactivity have gained in topically in the last years. For this reason the history of discovery of radon has been summed up. This history is one part of the early research about radioactivity. From the appearance of induced radioactivity the way leads to the discovery of thorium emanation by Rutherford and of radium emanation by Dorn. Finally, the article deals with the detection of radon in the air by Elster and Qeitel and of the radon in well water and springivaler by Thomson because only these results have opened the way for the therapeutical usage of radon.     

Enrico Fermi’s Discovery of Neutron-Induced Artificial Radioactivity:The Influence of His Theory of Beta Decay

We analyze the influence of Enrico Fermi’s theory of beta decay, which he formulated in December 1933, on his experimental discovery of neutron-induced artificial radioactivity four months later, in March 1934.We discuss Gian Carlo Wick’s application of Fermi’s theory in interpreting Frédéric Joliot and Irène Curie’s discovery of alpha-particle-induced artificial radioactivity, and how Fermi was then influenced by his theory in planning his neutron-bombardment experiments, in his decision to use a radon-beryllium (Rn-Be) neutron source, and in his choice of the elements he bombarded with Rn-Be neutrons. Our analysis is based crucially on Fermi’s first laboratory notebook, the Hirpine Notebook, which is preserved in the Oscar D’Agostino Archives in the Technical Institute “Oscar D’Agostino” in Avellino, Italy, and on the materials that are preserved in the Fermi Archives in the Domus Galilaeana in Pisa. These documents enable us to reconstruct Fermi’s discovery of neutron-induced artificial radioactivity and to assign an exact date to it of March 20, 1934.     

The potential health hazard due to elevated radioactivity in old uranium mines in Dolina Białego,Tatra Mountains,Poland

Natural radioactivity is one of the essential components of the environment. Unlike the Sudety mountains area in Poland, the Tatra Mountains were not the subject of wide survey as regards the levels of natural radioactivity. Especially, the concentrations of radon (natural radioactive gas) have not been investigated there in terms of their possible negative health impact. Within the frame of bilateral cooperation between the Institute of Nuclear Physics in Kraków, Poland, and the Jo?ef Stefan Institute in Ljubljana, Slovenia, the measurements of natural radioactive elements in old uranium mines in the Tatra National Park were performed in June 2010. The investigated sites were located in Dolina Bia?ego (The Valley of the White). One of the mines is situated near the tourist path. The paper presents the results of complex measurements of natural radioactivity in both uranium drifts. The concentration of radon gas inside the mining drifts exceeded 28,000 Bq m^?3. Also, very high gamma dose rates were observed (up to 5600 nSv h^?1). The maximum concentrations of natural radioactive elements (potassium ⁴⁰K, radium ²²⁶Ra, thorium ²³²Th) in rock samples amounted to 535, 2137, and 18 Bq kg^?1, respectively. The effective dose rates due to radon and thoron inhalation have been assessed as 0.013 mSv h^?1 (for the lowest concentration) and 0.121 mSv h^?1 (for the highest concentration).     

On the importance of the neutron number N=132 for asymmetric fission in the radium region

An analysis of the shell energy in terms of cluster contributions shows that the compound neutron number N=132 together with the (Z = 50)-substructure determines the border between symmetric and asymmetric fission in the Radium region. Possible experimental tests of this hypothesis are discussed.     

Charged particle fluxes in the near-ground atmosphere

In recent decades, interest in the environment has increased. The role of different factors, charged particles included, in the formation of aerosols and atmospheric electricity has been widely considered in the literature. Particle fluxes in atmospheric layers no more than several kilometers above Earth’s surface are especially important factors of weather conditions. These fluxes are due to cosmic rays and natural radioactivity. In this work, the composition of radiation is analyzed using long-term measurements of cosmic rays in the atmosphere, performed at different latitudes by the Lebedev Physical Institute of the Russian Academy of Sciences. Different components of charged particles fluxes in the near-ground atmosphere are estimated.     

Proton radioactivity within the generalized liquid drop model with various versions of proximity potentials

In the present work, we systematically investigate the proton radioactivity half-lives of spherical proton emitters adopting a generalized liquid drop model(GLDM) with 16 different proximity potentials, of which the proximity potential Prox.77-13 gives the closest results to the experimental data. Combined with the previous conclusion that the GLDM with proximity potential Prox.77-13 can also best describe α decay half-lives, which makes the model more uniform and consistent.Further, we use the proximity potential Prox.77-13 in GLDM to predict the proton radioactivity half-lives of 14 spherical proton emitters that are allowed energetically but not yet observed experimentally or specifically quantified. Finally, we research the Geiger-Nuttall law for proton radioactivity. The results reveal that the Geiger-Nuttall law can also be well used to study the proton radioactivity half-lives of isotopes with the same orbital angular momentum l.     

Visualization activities in Indonesia

Though it is still in its initial state, visualization techniques as one of the supportive components in the industrial transformation as well as a research tool have, however, gained some supports in universities and research institutes. This paper presents a review of activities related to the visualization research and application in universities and research institutes in Indonesia, namely at the Center for Applied Physics — Indonesia Institute for Sciences (P3FT-LIPI), University of Indonesia (UI), Institute of Technology Surabaya (ITS), Institute of Technology Bandung (ITB), and Aero-Gas Dynamics and Vibration Laboratory (LAGG-BPP-Teknologi).     

Radioactive analysis and radiological hazards in different types of Egyptian cement

Studies of the natural γ-emitting radionuclides in different types of cements manufactured by different companies in Egypt (e.g. Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan Ltd.) have been done to determine their natural levels of radioactivity using a high-purity germanium detector (HPGe). Knowledge of radioactivity present in cement materials enables one to assess any possible radiological risks to human health. The results show that the highest mean values of ²²⁶Ra and ²³²Th activity are 234.01±20.12 and 46.56±4.65 Bq kg^?1, respectively, measured in cement sample ‘Iron’ from Helwan company (HI). The corresponding value of ⁴⁰K is 333.53±26.68 Bq kg^?1 measured in cement sample ‘Karnak’ from Helwan company (HK). For ¹³⁷Cs, this value is 3.27±0.31 Bq kg^?1 measured in cement sample (HI). The average concentrations of measured radionuclides in the different cement samples are 72.21±6.39, 24.98±2.24, 134.49±10.45, and 0.58±0.08 Bq kg^?1 for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs, respectively. The measured activity concentrations for these radionuclides were compared with the reported data of other countries. Radium equivalent (Ra_eq) activities and different hazard indices were calculated to assess the radiation hazard. Iron HI cement sample shows a higher Ra_eq activity of 311.91±31.10 Bq kg^?1. Calculations of absorbed doses in nGy h^?1 show that the Iron (HI), Karnak (HK), and Super fine (HSu) products from Helwan company have higher activities than the permissible level (80 nGy h^?1). On the basis of the external hazard index (H _ex), Ra_eq activities, and annual effective dose rates for organs (H _organ), the natural radioactivity of cement samples is not greater than the recommended values in the established standards and hence safe for use in building constructions and therefore for inhabitants.     

Production of Hippuran-131I at Boris Kidrič Institute,Viněa Part II. Investigation of the Stability of Sodium ortho-131I-Hippurate as a Function of the Ageing Time,Presence of some Bacteriostatics and Stabilizers,Radioactivity, and the Sterilization Process of its Solutions

Stability of radioactive sodium ortho-¹³¹I-hippurate produced at the Boris Kidri? Institute, Vin?a, according to the modified procedure for application in nuclear medicine in Yugoslavia was investigated.

In these investigations stability was observed as a function of the ageing time of the solutions, their radioactivity (A mCi/ml; A mCi/mg of the carrier; A_tot), the presence of some bacteriostatics and stabilizers (C₆H₅—CH₂OH, Na-citrate), sterilization process and storage conditions.     

Cosmic-ray neutron spectrometry by solid state detectors

Extensive data have been gathered since the early 1990s on the response of different detectors based on the registration of neutron-induced fission in bismuth, gold, tantalum by the spark replica counter and the thin film breakdown counter. These detectors make it possible to exploit the excellent characteristics of the fission reactions in bismuth, gold and tantalum for the measurements of high-energy neutrons.

Most of the investigations have been carried out at the quasi-monoenergetic neutron beam facility at The Svedberg Laboratory-TSL of the Uppsala University in cooperation with the Khlopin Radium Institute (KRI).

The responses of different fission detectors in the intermediate range of neutron energy (35–180 MeV) have been evaluated: a region where the predictive power of available nuclear reaction models and codes is not reliable yet. For neutron energy greater than 200 MeV, the fission-detector responses have been derived from the data of the proton fission cross-sections.

Finally, by using the ratio of the responses of these detectors, a simple and accurate way to evaluate the spectrum hardness can be obtained, thus providing a tool to obtain spectral information needed for neutron dosimetry without the need to know the entire spectrum.

The experimentally measured spectra obtained to-date have different shapes and they are also different from those calculated.

In this paper, a new approach will be reported to analyse the existing spectra by using response ratios of different detectors. Preliminary data have been already obtained for the high-energy neutron spectrum from the CERN concrete facility.     

Uranium, radium and radon exhalation studies in some soil samples using plastic track detectors

Radium concentration and radon exhalation rate have been measured in soil samples collected from some areas belonging to upper Siwaliks of Kala Amb, Nahan and Morni Hills of Haryana and Himachal Pradesh states, India using LR-115 type II plastic track detectors. Uranium concentration has also been determined in these soil samples using fission track registration technique. Radium concentration has been found to vary from 5.30 to 31.71 Bq.kg⁻¹, whereas uranium concentration varies from 33.21 to 76.26 Bq.kg⁻¹. The radon exhalation rate in these samples varies from 216.87 to 1298.00 mBq.m⁻²hr⁻¹ (6.15 to 36.80 mBq.kg⁻¹.hr⁻¹). Most of the samples have uranium concentration above the worldwide average concentration of 35 Bq.kg⁻¹. A good correlation (R ² = 0.76) has been observed between uranium concentration and radon exhalation rate in soil. The values of uranium, radium and radon exhalation rate in soil are compared with that from the adjoining areas of Punjab.     

试论居里夫人的科研艺术

居里夫人关于放射性元素,特别是镭的发现与研究为原子物理学、放射化学和放射医学的发展奠定了基础,为此她先后获得了诺贝尔物理学奖和诺贝尔化学奖.居里夫人在科研过程中所运用的科学方法,如选题方法、实验方法、假说方法、逻辑思维方法等对现代的科技工作者仍具有重要的借鉴意义.     

CAFe DUMP前刮束器的设计研制

位于中国科学院近代物理研究所的超导直线加速器样机CAFe是一台质子超导直线加速器实验样机,围绕该装置的束流实验研究将为下一步设计研究加速器驱动次临界洁净核能系统(ADS)专用的超导直线加速器打下基础并提供经验。为了实现CAFe的10 mA束流指标,需要设计研制专门的束流收集器(DUMP)和对应的刮束器。本工作就CAFe DUMP前刮束器的研制进行了系统的设计和计算工作。刮束器面向束流侧的材料采用Al6063,确保束流轰击后的剩余放射性活度处于安全范围。基于蒙特卡罗粒子输运模拟,开展放射性核素及剩余剂量分析。结果表明,退役时刮束器外围剂量为可接受的百微希沃特每小时量级。通过ANSYS的热分析,计算了不同束流情况下刮束器的温度分布及温度变化,研究了刮束器在正常运行时移除热量的能力和在异常状况下应急保护的能力。计算结果表明,刮束器可以满足安全移除强流高功率束流束晕的设计需求。在CAFe高功率束流实验中,刮束器及DUMP运行正常,束流监测指标与设计一致,证明研制的刮束器实现了安全移除束晕、监测束流参数和保护DUMP的功能。     

Activation Characteristics of Fuel Breeding Blanket Module in Fusion Driven Subcritical System

Shortage of energy resources and production of long-lived radioactivity wastes from fission reactors are among the main problems which will be faced in the world in the near future. The conceptual design of a fusion driven subcritical system (FDS) is underway in Institute of Plasma Physics, Chinese Academy of Sciences. There are alternative designs for multi-functional blanket modules of the FDS, such as fuel breeding blanket module (FBB) to produce fuels for fission reactors, tritium breeding blanket module to produce the fuel, i.e. tritium, for fusion reactor and waste transmutation blanket module to try to permanently dispose of long-lived radioactivity wastes from fission reactors, etc. Activation of the fuel breeding blanket of the fusion driven subcritical system (FDSFBB) by D-T fusion neutrons from the plasma and fission neutrons from the hybrid blanket are calculated and analysed under the neutron wall loading 0.5 MW/m2 and neutron fluence 15 MW.yr/m2. The neutron spectrum is calculated with the worldwide-used transport code MCNP/4C and activation calculations are carried out with the well known European inventory code FISPACT/99 with the latest released IAEA Fusion Evaluated Nuclear Data Library FENDL-2.0 and the ENDF/B-V uranium evaluated data. Induced radioactivities, dose rates and afterheats, etc, for different components of the FDS-FBB are compared and analysed.     

The frame bundle picture of Gaussian wave packet dynamics in semiclassical mechanics

Letters in Mathematical Physics - Recently Ohsawa (Lett Math Phys 105:1301–1320, 2015) has studied the Marsden–Weinstein–Meyer quotient of the manifold $$T^*\mathbb {R}^n\times...     

Observation of inverse Meyer–Neldel rule in thermally activated crystallization of a hybrid composite of phenol formaldehyde

We report the inverse Meyer–Neldel (MN) rule in the thermally activated crystallization of a hybrid composite of phenol formaldehyde using two experimental approaches. In the first experiment, the annealing time dependence of the pre-exponential factor K ₀ and the activation energy of crystallization E _c were studied. In the second experiment, the annealing temperature dependence of the same parameters was investigated. We observed the inverse Meyer–Neldel rule between the pre-exponential factor K ₀ and the activation energy of crystallization E _c in both cases.     

Influence of proton irradiation on electrical properties of Y-Ba-Cu-O thin films

One of the authors (P. K.) wishes to express his gratitude to Dr. O. Meyer and his technical staff for providing him with the experimental facilities in the Institut für Nukleare Festkörperphysik, Karlsruhe.