A fast method to measure the thickness of removed layer from etching of SSNTD based on EDXRF

Solid state nuclear track detectors are commonly used for measurements of concentrations of radon gas and/or radon progeny. All these measurements depend critically on the thickness of the removed layer during etching. However, the thickness of removed layer calculated using the etching period does not necessarily provide a sufficiently accurate measure of the thickness. For example, the bulk etch rate depends on the strength of stirring during etching for the LR 115 detector. We propose here to measure the thickness of the removed layer by using energy-dispersive X-ray fluorescence spectrometry. In the present work, a reference silver nitrate pellet is placed beneath the LR 115 detector, and the fluorescence X-ray intensity for silver is then measured. We have found a linear relationship between the X-ray intensity and the thickness of the removed layer for LR 115 detector. This provides a fast method to measure the thickness of removed layer from etching of LR 115 detector. However, this method was found to be inapplicable for the CR-39 detector. Therefore, alternative methods have yet to be explored for the CR-39 detector.     

Separation of Macroamounts of Metal Pairs – Part 1. Separation of Cadmium and Cobalt

The separation factors of cadmium and cobalt were performed on varying cadmium, zinc and cobalt concentrations in the original aqueous solution. A long chain amine (Amberlite LA-2) and an organophosphorus solvent (TBP) have been investigated. In most cases the values of the separation factor increases with the increase of metal concentration in the aqueous phase. The various possibilities of chemical and radiochemical separations of the metal pair are reported.     

Study of indoor radon and thoron progeny levels in surrounding areas of Nalbari, Assam, India

With the growing understanding of the role of radon and its daughter products as major sources of radiation exposure, the importance of large number of estimation of radon concentration in various parts of the country is realized. Inhalation of radon, thoron and their decay products is the major source of the total radioactive dose received by the human population from natural radiation. The indoor radon and thoron progeny levels in Nalbari area of Assam are studied by using the LR-115 (type II) Solid State Nuclear Track Detector in Plastic Twin Chamber dosimeter. Radon and thoron progeny levels in different types of dwellings for one full calendar year are presented in this paper. For Assam Type (A.T.) houses, indoor radon progeny concentrations vary from 0.17 to 0.64 mWL with an annual geometric mean of 0.27 mWL and that for Reinforced Cement Concrete (R.C.C.) houses vary from 0.22 mWL to 0.60 mWL with the annual geometric mean of 0.37 mWL. The thoron progeny levels in A.T. houses also vary from 0.01 to of 0.05 mWL with an annual geometric mean of 0.02 mWL and that for R.C.C. houses vary from 0.02 to 0.08 mWL with the annual geometric mean of 0.04 mWL.      

Comparison of responses of LR-115A, CR-39 and PM-355 track detectors to pulsed low-energy proton streams

The paper concerns applications of LR-115A, CR-39 and PM-355 solid-state nuclear-track detectors (SSNTDs) for investigation of pulsed fluxes of protons below 300 keV. The proton streams were generated by the RPI-IBIS device operated with hydrogen puffing [Baranowski et al. 2000. Studies of hydrogen discharges in RPI-type devices with different electrode configurations. Czech. J. Phys. 50 (Suppl. S3), 101–107]. To perform ion mass- and energy-analysis, a Thomson mass-spectrometer equipped with a special input system and exchangeable detectors was used. A quantitative analysis of proton tracks upon Thomson parabolas was performed by means of an optical microscope equipped with a CCD camera. It made possible to measure proton tracks and to determine their statistics. The paper presents proton energy spectra recorded with the selected detectors, and responses of these detectors to protons of energy from about 30 to 300 keV. The results are important for verification of detector characteristics and for measurements of protons at different experimental conditions.     

A comparative study of indoor radon level measurements in the dwellings of Punjab and Himachal Pradesh, India

The LR-115 type-II plastic track detector has been used for measuring the indoor radon levels in the dwellings of some villages of Punjab and Himachal Pradesh. In Punjab, the villages surveyed are Rampura Phul, Lehra Mahabat and Pitho (villages in Bathinda district), and Amritsar city. The average indoor radon levels in these areas are found to vary from 64 to 152 Bq/m³, which are quite within the safe limits recommended by International Commission on Radiological Protection (Ann. ICRP 23(2)). The indoor radon levels have also been measured in the dwellings of Hamirpur district of Himachal Pradesh. The villages surveyed in this area are Nukhel, Badarn, Galore-Khas, Har-Upper, Tikker Brahamana and Awah-Lower where radon concentration has been found to vary from 261 to 724 Bq/m³. These values are higher than the recommended limit.     

Aktivierungsanalytische Untersuchung von Zirkoniumlegierungen

Durch Aktivierungsanalyse mit Reaktorneutronen (zerstörungsfrei und mit chemischer Aufarbeitung) sowie mittels zerstörungsfreier Untersuchungen an einem Neutronengenerator wurden O, Al, Si, P, Mn, Cu, Nb, Mo, Cd, Ti, Cr und Hf in Zirkoniumlegierungen bestimmt.     

Phase diagram calculation on Sn-Zn-Ga solders

Sn-Zn eutectic system is one of the most promising lead-free solders with the advantages of low melting points, excellent mechanical properties and acceptable costs, whereas its poor wetting ability confines its applications in many substrates. In this paper, gallium (Ga) was added to the Sn-Zn eutectic system in order to improve its melting properties and wetting abilities. Piecing binary phase diagram method was employed to calculate the uncharted Sn-Zn-Ga ternary phase diagram and the eutectic point of this ternary system. Differential scanning calorimeter (DSC) method was used to exam the melting point of the solder system. The SnZn6Ga solder has a melting point of 174.4 °C, with wetting rate of 48.9%, while the melting point of Sn-Zn alloy is 198.5 °C and melting rate is only about 20%. In addition, the method of piecing binary phase diagrams proves to be feasible to clarify certain unknown ternary phase systems.     

Stopping power of 1.0–2.6 MEV protons in Mylar, Makrofol and cellulose nitrate foils

Stopping powers of 1.0 – 2.6 MeV protons in Mylar, Makrofol and Cellulose nitrate were measured. The results have been compared with scanty experimetnal data in the literature and with calculated values obtained by using the TRIM 92 computer code. These values agree well with each other within uncertainties. In the case of Mylar and LR 115, maximum deviations of 9.5% and 4.5% from the semi-emperical curves were observed. In the case of Makrofol foils, a maximum deviation of 3% was found. Considering the accuracy of theories this discrepancy is not that significant.     

Observation of nuclear track in organic material by Atomic Force microscopy in real time during etching

The developments of Atomic Force Microscopy (AFM) allow to investigated solid surfaces with a nanometer scale. These techniques are useful methods allowing direct observation of surface morphologies. Particularly in the nuclear track fields, they offer a new tool to give many new informations on track formation. In this paper we present the preliminary results of a new use of this technique to characterize continuously the formation of the revealed track in a cellulose nitrate detector (LR115) after an alpha particle irradiation. For that, a specific cell has been used to observe, by nano-observations, the evolution of track shapes simultaneously with chemical treatment. Thus, the track shape evolution has been studied; visualizing the evolution of the tracks in real time, in situ during the chemical etching process.     

Properties of some high Al content glasses in various lanthanide-Si-Al-O-N systems

A review of some behaviour diagrams in the Y-Si-Al-O-N system indicate that the liquid region, and hence the glass forming region, could be more extensive than previously documented. Apart from the glass-forming region of Drew et al. [Special Ceramics 7, Brit. Ceram. Proc., vol. 31, The British Ceramic Society, Stoke-on-Trent, UK, 1981, p. 119] at 1700 °C, the solid-liquid reactions in the β-SiAlON-Y₃Al₅O₁₂ seen as liquid isotherms at 1550, 1650 and 1750 °C are indicated by Tien [Silicon Nitride Ceramics Scientific and Technological Advances, Materials Research Society Symposium Proceedings, vol. 287, MRS Pittsburgh, 1993, p. 51]. Other researchers [J. Eur. Ceram. Soc. 17 (1997) 789] have studied the nitrogen-rich liquid phase regions in the Ln-Si-Al-O-N systems (40 e/o N). In the current work, selected compositions with high Al/Si ratio in the aluminium-rich part of these systems (52-62 e/o) were fired at 1700 °C. Properties have been investigated and compared with ‘standard’ glass compositions (i.e. 28M:56Si:16Al:83O:17N e/o) [J. Eur. Ceram. Soc. 17 (1997) 1933] where M=La, Nd, Sm, Dy, Er, Yb, Y.