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This work investigated the electronic and structural properties of sodium iodide using the Density Functional Theory (DFT) method implemented in the quantum espresso code. The GGA (PBE) functional with exchange correlation was used. Convergence test for the kinetic energy cut-off, k-point and lattice parameter was carried out and the parameter generated was found to be consistent with the crystallography open data base input file of the sodium iodide. Band structure was plotted, and band gap was calculated to be 3.87 eV which was found to be in the category of a semiconductor but with high resistivity and low resolution. The plot of density of state was revealed that electrons may be scarcely found within some state in the sodium iodide crystal. The research shows that sodium Iodide can be effective as a semiconductor in the presence of dopants e.g., thallium which is often used in a radiation detection.

This work investigated the electronic and structural properties of sodium iodide using the Density Functional Theory (DFT) method implemented in the quantum espresso code. The GGA (PBE) functional with exchange correlation was used. Convergence test for the kinetic energy cut-off, k-point and lattice parameter was carried out and the parameter generated was found to be consistent with the crystallography open data base input file of the sodium iodide. Band structure was plotted, and band gap was calculated to be 3.87 eV which was found to be in the category of a semiconductor but with high resistivity and low resolution. The plot of density of state was revealed that electrons may be scarcely found within some state in the sodium iodide crystal. The research shows that sodium Iodide can be effective as a semiconductor in the presence of dopants e.g., thallium which is often used in a radiation detection.

Magmatic rocks represent one of the most significant rocks due to their abundance, durability and appearance; they can be used as ornamental stones in the construction of dwellings. The current study is concerned with the detailed petrography and natural radioactivity of seven magmatic rocks. All are commercial granitic rocks and are identified as black Aswan, Nero Aswan, white Halayeb, Karnak, Verdi, red Hurghada and red Aswan. Their respective mineralogical com-positions are classified as porpheritic granodiorite, granodiorite, tonalite, monzogranite, syenogran-ite, monzogranite and syenogranite. A total of nineteen samples were prepared from these seven rock types in order to assess their suitability as ornamental stones. Concentrations of 226Ra, 232Th and 40K radionuclides were measured using NaI (Tl) scintillation gamma-ray spectrometry. Among the studied magmatic rocks, white Halayeb had the lowest average values of226Ra (15.7 Bq/kg),232Th (4.71 Bq/kg) and40K (~292 Bq/kg), all below the UNSCEAR reported average world values or rec-ommended reference limits. In contrast, the other granitic rocks have higher values than the recom-mended limit. Except for the absorbed dose rate, other radiological hazard parameters including radium equivalent activity, annual effective dose equivalent, external, and internal hazard indices reflect that the White Halyeb rocks are favorable for use as ornamental stone in the construction of luxurious and high-demand residential buildings. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

The specific activity of 40K, 232Th and 226Ra in marine sediment samples collected from National Institute of Oceanography and Fisheries (NIOF) and Safier Hotel area in Hurghada city (the most important regions in Egypt), were measured by gamma ray spectrometry using NaI(Tl) detector. The values of specific activity varied from 7 ± 1 Bq kg-1 to 53 ± 4 Bq kg-1, 6 ± 1 Bq kg-1 to 32 ± 6 Bq kg-1, and from 167 ± 11 Bq kg-1 to 1120 ± 63 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The heavy metals have been measured and analysed by atomic absorption spectrometer. The major range values of heavy metals concentrations in marine sediment samples were: Cu (10.5-78.0 μg g-1), Zn (21-150 μg g-1), Pb (30-53 μg g-1), Cd (2.50-4.00 μg g-1), Fe (5100-13150 μg g-1), Mn (118-298 μg g-1), Ni (17-36 μg g-1) and Co (16-18 μg g-1). The total organic matter (TOC) and carbonates (CaCo3) distribution have been measured at some locations. Also, the frequency distribution and the value of (232Th/226Ra), (232Th/40K) and (226Ra/40K) ratio for all measured samples were determined. Additionally, evaluations have been made of the radiological hazards and the results are diagrammed by Surfer program in maps. © Penerbit Universiti Sains Malaysia, 2019.

The Cryogenic Observatory for SIgnals seen in Next-generation Underground Searches (COSINUS) project aims to provide a model-independent cross-check of the long-standing DAMA/LIBRA claim on the observation of dark matter by using the same target material, but in a different experimental approach. Operating sodium iodide (NaI) scintillating crystals as low-temperature scintillating calorimeters has the distinct advantage of providing a lower energy threshold for nuclear recoil events as expected from dark matter particle interactions combined with particle discrimination. The dual readout of phonon and light allows us to provide background rejection on an event-by-event basis, a unique feature in comparison with other NaI-based dark matter searches. The manuscript discusses in detail the COSINUS detector concept and presents the results and performance parameters from our second prototype detector.

Application of NaI(Tl) detectors in the search for galactic dark matter particles through their elastic scattering off the target nuclei is well motivated because of the long standing DAMA/LIBRA highly significant positive result on annual modulation, still requiring confirmation. For such a goal, it is mandatory to reach very low threshold in energy (at or below the keV level), very low radioactive background (at a few counts/keV/kg/day), and high detection mass (at or above the 100 kg scale). One of the most relevant technical issues is the optimization of the crystal intrinsic scintillation light yield and the efficiency of the light collecting system for large mass crystals. In the frame of the ANAIS (Annual modulation with NaI Scintillators) dark matter search project large NaI(Tl) crystals from different providers coupled to two photomultiplier tubes (PMTs) have been tested at the Canfranc Underground Laboratory. In this paper we present the estimates of the NaI(Tl) scintillation light collected using full-absorption peaks at very low energy from external and internal sources emitting gammas/electrons, and single-photoelectron events populations selected by using very low energy pulses tails. Outstanding scintillation light collection at the level of 15 photoelectrons/keV can be reported for the final design and provider chosen for ANAIS detectors. Taking into account the quantum efficiency of the PMT units used, the intrinsic scintillation light yield in these NaI(Tl) crystals is above 40 photons/keV for energy depositions in the range from 3 up to 25 keV. This very high light output of ANAIS crystals allows triggering below 1 keV, which is very important in order to increase the sensitivity in the direct detection of dark matter.

Background and Purpose: In vitro experimental investigations of haemodynamic profiles inside two patient-specific silicone models of intracranial aneurysms were carried out with the aid of a non-intrusive particle image velocimetry (PIV) measurement technique. Multi-plane fluid flow structures, including two-dimensional time-mean velocities as well as their fluctuating components, across the aneurysm model were obtained before and after the deployment of a flow diverting stent. Moreover a high-speed camera was employed to visualise the effectiveness of the flow diverter on intra-aneurysmal flow patterns. Both qualitative and quantitative experimental data will not only help the fundamental understanding of the haemodynamic phenomena occurring in the intracranial aneurysms, but be utilised to validate the numerical predictions using computational fluid dynamics (CFD). Material(s) and Method(s): Two patient-specific, full-scale silicone models of aneurysms were fabricated using rapid prototyping and 3D printing techniques. The working fluid used was a mixture of sodium iodide, glycerol and distilled water with its refractive index matching to the silicone resin. The 2D PIV system consisted of a CCD camera, a Nd:YAG pulsed laser and a synchroniser. Rhodamine B fluorescent particles were used as the seeding particles for the PIV measurements. At each measuring plane, 400 pairs of successive images were taken at the laser repetition rate of 4 Hz. Hence a mean velocity flow pattern at that plane was obtained by statistically averaging 400 successive instantaneous velocity vector maps over a time period of approximately two minutes. Result(s): The multi-plane intra-aneurysmal flow patterns under various flow rates from 80 ml/min to 470 ml/min were obtained before and after the deployment of the flow diverter. It was clearly observed from the quantitative PIV measurements that the overall averaged velocity magnitude at one particular plane had a four-to-seven-fold decrease

Background and Purpose: In vitro experimental investigations of haemodynamic profiles inside two patient-specific silicone models of intracranial aneurysms were carried out with the aid of a non-intrusive particle image velocimetry (PIV) measurement technique. Multi-plane fluid flow structures, including two-dimensional time-mean velocities as well as their fluctuating components, across the aneurysm model were obtained before and after the deployment of a flow diverting stent. Moreover a high-speed camera was employed to visualise the effectiveness of the flow diverter on intra-aneurysmal flow patterns. Both qualitative and quantitative experimental data will not only help the fundamental understanding of the haemodynamic phenomena occurring in the intracranial aneurysms, but be utilised to validate the numerical predictions using computational fluid dynamics (CFD). Material(s) and Method(s): Two patient-specific, full-scale silicone models of aneurysms were fabricated using rapid prototyping and 3D printing techniques. The working fluid used was a mixture of sodium iodide, glycerol and distilled water with its refractive index matching to the silicone resin. The 2D PIV system consisted of a CCD camera, a Nd:YAG pulsed laser and a synchroniser. Rhodamine B fluorescent particles were used as the seeding particles for the PIV measurements. At each measuring plane, 400 pairs of successive images were taken at the laser repetition rate of 4 Hz. Hence a mean velocity flow pattern at that plane was obtained by statistically averaging 400 successive instantaneous velocity vector maps over a time period of approximately two minutes. Result(s): The multi-plane intra-aneurysmal flow patterns under various flow rates from 80 ml/min to 470 ml/min were obtained before and after the deployment of the flow diverter. It was clearly observed from the quantitative PIV measurements that the overall averaged velocity magnitude at one particular plane had a four-to-seven-fold decrease

Nuclear Compton scattering — the elastic scattering of photons — from 12C has been studied at the Tagged-Photon Facility at MAX IV in Lund, Sweden. The differential cross section for the reaction was determined at laboratory angles of 60° and 120° in the energy range 65-95 MeV. The cross section for nuclear Compton scattering is related to the electric and magnetic polarisabilities of the proton and the neutron. The polarisabilities are fundamental structure constants that describe how nucleons are affected by an external electromagnetic field. The determination of the electric and magnetic polarisabilities of the neutron through measurements of the deuterium Compton scattering cross section is the goal of a recent large scale experimental effort spanning almost a decade at the Tagged-Photon Facility at MAX IV. The purpose of this experiment was twofold: to verify the procedure for normalisation of Compton scattering data by investigating 12C and comparing to a well-established and comprehensive existing body of data, and to determine whether the electric and magnetic polarisabilities of free nucleons are affected when they are bound inside a nucleus.

Nuclear Compton scattering — the elastic scattering of photons — from 12C has been studied at the Tagged-Photon Facility at MAX IV in Lund, Sweden. The differential cross section for the reaction was determined at laboratory angles of 60° and 120° in the energy range 65-95 MeV. The cross section for nuclear Compton scattering is related to the electric and magnetic polarisabilities of the proton and the neutron. The polarisabilities are fundamental structure constants that describe how nucleons are affected by an external electromagnetic field. The determination of the electric and magnetic polarisabilities of the neutron through measurements of the deuterium Compton scattering cross section is the goal of a recent large scale experimental effort spanning almost a decade at the Tagged-Photon Facility at MAX IV. The purpose of this experiment was twofold: to verify the procedure for normalisation of Compton scattering data by investigating 12C and comparing to a well-established and comprehensive existing body of data, and to determine whether the electric and magnetic polarisabilities of free nucleons are affected when they are bound inside a nucleus.

The United States Air Force School of Aerospace Medicine, Consultative Services Division investigated false neutron counts with the Berkeley Nucleonics Corp. Model 940-2GN surveillance and measurement radioisotope identification system (SAM 940-2GN). This portable instrument is a standard component of the Bioenvironmental Engineering (BE) 886H Allowance Standard. In the presence of high-activity gamma fields, it has been demonstrated that the SAM 940-2GN will report neutron counts erroneously, which is due to cross-talk within the detector, and can be thought of as a ?false positive.? This letter provides a prediction of false neutron response in high-activity gamma environments based on empirical data. Additionally, the letter gives a decision matrix so BE personnel can appropriately assess SAM 940-2GN neutron counts and avoid potential misclassification of a source as a neutron emitter.

Nuclear physics research is focused upon determining the structure of the atomic nucleus and nuclei, and understanding the interactions both within it and between them. To accomplish this, various probes of the nucleus are used - two types are 'electromagnetic' and 'hadronic'. An example of an electromagnetic probe is the photon, which has the advantage of interacting with the nucleus via the very well-understood electromagnetic force. At MAX-lab, tagged photons are produced using an electron beam. In order to detect these photons, different detectors may be used: sodium iodide and Pb-glass are two examples. In order to produce meaningful results, such detectors must first be calibrated by applying physically well-motivated and understood corrections. The detectors have to be calibrated both relatively and absolutely in terms of their timing and the amount of deposited energy they register. A detailed overview of such calibrations is presented in this thesis, which is based upon data acquired at MAX-lab during the June and September 2011 and April 2012 run periods.

Nuclear physics research is focused upon determining the structure of the atomic nucleus and nuclei, and understanding the interactions both within it and between them. To accomplish this, various probes of the nucleus are used - two types are 'electromagnetic' and 'hadronic'. An example of an electromagnetic probe is the photon, which has the advantage of interacting with the nucleus via the very well-understood electromagnetic force. At MAX-lab, tagged photons are produced using an electron beam. In order to detect these photons, different detectors may be used: sodium iodide and Pb-glass are two examples. In order to produce meaningful results, such detectors must first be calibrated by applying physically well-motivated and understood corrections. The detectors have to be calibrated both relatively and absolutely in terms of their timing and the amount of deposited energy they register. A detailed overview of such calibrations is presented in this thesis, which is based upon data acquired at MAX-lab during the June and September 2011 and April 2012 run periods.

Vascular supply is an obvious requirement for all organs. In addition to oxygen and nutrients, blood flow also transports essential trace elements. Iodine, which is a key element in thyroid hormone synthesis, is one of them. An inverse relationship exists between the expansion of the thyroid microvasculature and the local availability of iodine. This microvascular trace element-dependent regulation is unique and contributes to keep steady the iodide delivery to the thyroid. Signals involved in this regulation, such as VEGF-A, originate from thyrocytes as early TSH-independent responses to iodide scarcity. The question raised in this paper is how thyrocytes, facing an acute drop in intracellular stores of iodine; generate angiogenic signals acting on adjacent capillaries. Using in vitro models of rat and human thyroid cells, we show for the first time that the deficit in iodine, is related to the release of VEGF-A via a reactive oxygen species/hypoxia inducible factor-1-dependent pathway. Key words: thyroid function, angiogenesis - VEGF, ROS, iodine, HIF.

Free radical damage and fibrosis caused by selenium deficiency are thought to be involved in the pathogenesis of myxoedematous cretinism. So far, no pathway explains the link between selenium deficiency and tissue fibrosis. Pharmacological doses of iodine induce necrosis in iodine-deficient thyroids. Necrosis is much increased if the glands are also selenium-deficient, which then evolve to fibrosis. This rat model was reproduced to explore the role of selenium deficiency in defective tissue repair. At first, proliferation indexes of epithelial cells and fibroblasts were comparable between selenium-deficient and control groups. Then, in selenium-deficient thyroids the inflammatory reaction was more marked being mainly composed of macrophages. The proliferation index of the epithelial cells decreased, while that of the fibroblasts increased. These thyroids evolved to fibrosis. TGF-beta immunostaining was prominent in the macrophages of selenium-deficient rats. Anti TGF-beta antibodies restored the proliferation indexes, and blocked the evolution to fibrosis. In selenium deficiency, an active fibrotic process occurs in the thyroid, in which the inflammatory reaction and an excess of TGF-beta play a key role.

The purpose of this research is to investigate the angular resolution, efficiency, and energy resolution possible from a portable Compton camera gamma ray imaging system for possible use in the field of nuclear nonproliferation. The proposed device uses room temperature semiconductor and position sensitive scintillation detectors. The position and energy resolution (and their energy dependence) of a room temperature lithium drifted silicon (Si(Li)) detector and a position sensitive thallium -doped sodium iodide (NaI(Tl)) scintillation detector are investigated. The position and energy resolution of the position sensitive scintillation detector is also modeled computationally, and the results compared to measured data. An efficiency model is also presented. The angular resolution, efficiency, and energy resolution of the proposed system are calculated. The same computational methods are then applied to a hypothetical position sensitive Thallium doped cesium iodide (CsI(Tl)) scintillator. Based on the results, the angular resolution and energy resolution of a system employing this type of position sensitive detector coupled to the same room temperature Si(Li) detector is predicted.

Iodine deficiency disorders are major problems in most developing countries. According to WHO more than one billion people worldwide are at risk for iodine deficiency. However, prophylaxis programs based on the distribution of iodized salt have been unsuccessful in developing countries for socioeconomic reasons. We tested the efficacy of iodination of water with sodium iodide incorporated into silicone matrices (Rhône-Poulenc-Rorer-Doma). Nine such matrices were placed into each of the 198 wells supplying more than 90% of the 85,037 inhabitants of the Nana-Grebizi prefecture (figure 1). Efficacy was evaluated by following classical markers of iodine deficiency in representative samples of the population (figure 2): goiter size was measured immediately before (T = 0, n = 3,090) and twelve months after (T = 12, n = 2,645) installation of the matrices; and urinary iodine concentrations were assayed at T = 0 (n = 319), 6 (n = 304) and 12 (n = 261). The prevalence of goiter was 60.9% (visible goiter 10.7%, cretinism 0.7%) and the median urinary iodine concentration was 2.1 (95% confidence interval 2.0-2.3) micrograms/dl. Thus the population suffered from severe iodine deficiency. All villages were severely affected, despite inter-village variations (tables 1 and 2, figure 4). Twelve months after iodination of wells, the overall prevalence of goiter fell to 44.5% (p < 0.0001, table 1 and figure 3) and that of visible goiter to 2.5% (p < 0.0001). With the exception of one village (Bokanzi) the prevalence of goiter decreased by 18.6 to 56.3% (table 1).(ABSTRACT TRUNCATED AT 250 WORDS), English Abstract, Journal Article, info:eu-repo/semantics/published

Iodine deficiency disorders are major problems in most developing countries. According to WHO more than one billion people worldwide are at risk for iodine deficiency. However, prophylaxis programs based on the distribution of iodized salt have been unsuccessful in developing countries for socioeconomic reasons. We tested the efficacy of iodination of water with sodium iodide incorporated into silicone matrices (Rhône-Poulenc-Rorer-Doma). Nine such matrices were placed into each of the 198 wells supplying more than 90% of the 85,037 inhabitants of the Nana-Grebizi prefecture (figure 1). Efficacy was evaluated by following classical markers of iodine deficiency in representative samples of the population (figure 2): goiter size was measured immediately before (T = 0, n = 3,090) and twelve months after (T = 12, n = 2,645) installation of the matrices; and urinary iodine concentrations were assayed at T = 0 (n = 319), 6 (n = 304) and 12 (n = 261). The prevalence of goiter was 60.9% (visible goiter 10.7%, cretinism 0.7%) and the median urinary iodine concentration was 2.1 (95% confidence interval 2.0-2.3) micrograms/dl. Thus the population suffered from severe iodine deficiency. All villages were severely affected, despite inter-village variations (tables 1 and 2, figure 4). Twelve months after iodination of wells, the overall prevalence of goiter fell to 44.5% (p < 0.0001, table 1 and figure 3) and that of visible goiter to 2.5% (p < 0.0001). With the exception of one village (Bokanzi) the prevalence of goiter decreased by 18.6 to 56.3% (table 1).(ABSTRACT TRUNCATED AT 250 WORDS), English Abstract, Journal Article, info:eu-repo/semantics/published

To evaluate the involvement of T cell immunity in the thyroiditis induced in goitrous mice by iodide administration, we analyzed the immunological changes happening in the thyroid glands and lymph nodes during goiter involution in balb/c and athymic nude mice of similar background. In both balb/c and nude mice, goiter involution was characterized by thyroid cell necrosis and inflammation. In balb/c mice, the inflammatory infiltrate was made of numerous Ia+ cells. Their number was unchanged during goiter development, but was significantly increased after 2 days of involution and remained high after 8 days. CD4+ and CD8+ T cells were also observed, some of which were clearly activated since they expressed the receptor for Interleukin-2 (IL-2R). The numbers of CD4+, CD8+ and IL-2R+ T cells were increased during goiter as compared to control mice, and they reached a maximum at day 1 of involution. In nude mice, unexpectedly, CD4+ and CD8+ T cells were also found in the thyroid. Their numbers, as well as the number of Ia+ cells, were significantly increased at the onset of involution, but they remained systematically lower than in the corresponding groups of balb/c mice. Iodide treatment of goitrous mice also induced modifications of the lymph nodes draining the thyroid: enlargement of the paracortical T zone, presence of germinal centers in cortical follicles, and increase of the density of IL-2R+ cells. Mesenteric lymph nodes taken as controls were unchanged. Thus, three observations suggest the involvement of T cell immunity in iodine-induced thyroid inflammation: 1. Infiltration of Ia+, CD4+, CD8+ and IL-2R+ cells. 2. Signs of stimulation in thyroid lymph nodes, 3. Significant differences between balb/c and nude mice, in which the inflammatory reaction is weaker.

In potato, cytochrome c reductase, a protein complex of the respiratory chain, exhibits processing activity toward mitochondrial precursor proteins. One of the two cooperating components of the processing peptidase was shown to be identical with subunit III of the complex. Here we report that two additional proteins of the complex (subunit I and II) share 40-50% sequence identity with the processing enhancing protein, the other component of the processing enzyme from fungi and mammals. Thus the composition and structure of the complex integrated processing peptidase seems to be different from its fungal and mammalian counterparts. Cytochrome c reductase from potato is extraordinarily stable, and separation of subunit III from the complex leads to aggregation of the remaining subcomplex and irreversible loss of processing activity. Expression of the three high molecular weight subunits of the complex allowed purification of each individual protein. Neither the individual subunits nor their combinations are active in in vitro processing assays suggesting that they may need the structural support of the complex for activity. In contrast to mitochondrial processing peptidases from other organisms, the purified potato enzyme is active in the presence of high salt (above 1 M NaCl) and works efficiently without addition of metal ions. These data indicate that potato cytochrome c reductase is a bifunctional protein complex with unique features. Possibly, there is a more general evolutionary relationship between cytochrome c reductases and mitochondrial processing peptidases than hitherto assumed.

The acute effects of increasing doses of sodium iodide were studied on human thyroid follicles isolated from normal paranodular tissue. After 24 h incubation in culture medium, follicles isolated from most thyroids maintained their capacity for 125I accumulation and organification and a normal cellular ultrastructure. 125I accumulation was significantly increased after addition of TSH, whereas 125I organification was not affected. In presence of TSH, numerous follicles had large empty-looking follicular lumina unlabeled on autoradiographies. Follicles incubated for 24 h in the presence of a low concentration (10(-7) M) of iodide retained their function and morphology. However, incubation with a high dose of iodide (10(-3) M) caused marked inhibition of 125I accumulation and organification reaching values similar to those obtained in presence of inhibitors of iodide trapping and organification. At high doses, iodide induced necrosis of thyroid epithelial cells: the percentage of necrotic cells was significantly increased with 10(-5) M and doubled with 10(-3) M as compared to values measured at 10(-7) M. Ultrastructural lesions such as apical blebbing, cytoplasmic fragments desquamation, endoplasmic reticulum vesiculation, and accumulation of lipofuscin in secondary lysosomes were also present. The necrotic effect and the ultrastructural alterations also occurred in the presence of TSH but were prevented by the addition of inhibitors of iodide trapping or organification. These results demonstrate a direct acute toxic effect of iodide in human thyroid cells. The nature of the ultrastructural alterations is in agreement with a mechanism of toxicity involving a free radical attack and lipid peroxidation as observed in other tissues.

The major findings realized from this year's effort are: (1) At approx. 40% RH, the NWC 90 and NWC 164 pyrotechnics appear to provide greater extinction at IR wavelengths longer than approx. 7 micron relative to the other pyrotechnics. This performance may be due to the graphite component of the NWC 90 and NWC 164 aerosol. (2) At approx. 75% RH, extinction produced by NWC 29, NWC 78, NWC 79, NWC 90 and NWC 164 is approximately a factor of four greater than that provided by CY85A. (3) At approx. 90% RH, all six pyrotechnics provide approximately the same degree of extinction effectiveness. (4) The nominal mass yields for the six pyrotechnics appear equivalent. Values ranged from 28 to 37%. (5) Based on SEM analyses of individual particles in the size range 0.2 to 1.9 micrometer, no evidence was seen supporting a significant particle size-chemical composition relationship for the evaluated pyrotechnics. (6) The eutonic mixture of MgCl2 - NaCl and the estimated eutonic mixtures of MgCl2 - NaI provided no decrease in the deliquescence humidity relative to the deliquescence humidity of pure MgCl2. (7) The eutonic mixture of NaCl - KCl provided a 2% RH decrease in the humidity at which deliquescence began relative to pure NaCl.

Surface Raman spectra of a silver electrode contacting with an acidic solution containing triethylenediamine (DABCO) and sodium iodide showed some new Raman peaks, which were neither the peaks of dissolved DABCO species nor of iodide. These were ascribed to diprotonated DABCO polyiodide crystal, formed and attached onto the laser-irradiated site of the silver electrode. Several facts implied that laser illumination used for the Raman measurement promoted the growth of the crystal; the possibility of photoinduced electrochemical crystal formation was suggested. The mechanisms for this local crystal growth of diprotonated DABCO polyiodide on the silver electrode was examined, as to its dependence upon the solution composition and applied potential. Keywords: Laser-induced crystal growth.

A versatile gamma-ray detecting system has been brought into operation. It is a coincidence-anticoincidence Ge(Li)-NaI(Tl) spectrometer, mounted on a turntable to permit the measurements of angular distributions of gamma radiations, produced by nuclear reactions involving charged particles. It consists of a central 20 cc Ge(Li) detector surrounded by a large NaI(Tl) annulus which is split into two optically-insulated halves. The method of processing events allows four different spectra to be stored simultaneously under identical gain conditions. Initial experiments using this system are outlined, as well as possible future uses and developments. For purposes of comparison, other new systems are described. (Author)

Chemistry of oxygen - fluorine compounds O2F2, O3F2, O4F2 compounds NF4(), N2F5(), and H2NF2() ions.

Trans. of Ukrayins'kyy Fizychnyy Zhurnal (USSR), v7 n10 p1101-1104, 1962.

The sodium D2 line Doppler profile was measured from observed fluorescence of the electronically excited sodium atom generated by photodissociation of NaI by ultraviolet wavelength light in the 2100-2500A region. The experimentally determined Doppler profile is compared to an ideal Doppler profile calculated by considering the vibrational and rotational states of the NaI molecule and by considering the excited sodium atom recoil velocities and the most probable NaI thermal speeds. Effect of polarization of the exciting ultraviolet on the angular velocity distribution of the dissociation products of NaI was measured.

The properties of a large NaI(T1) detector as a total absorption detector for pions at GeV energies are reported. These observations are supplemented by measurements on the three-dimensional distribution of deposited energy in a large absorber of metallic tin by 8 GeV pions. The latter data are compared with existing Monte Carlo calculations of the nucleon-meson cascade and their application to the design of total absorption detectors with large containment factors is discussed. (Author)

Contents include: Vaporization in insufflation of powdered materials into an electric-discharge plasma; High-frequency electrodeless discharge; Prism resonators; Gain on singlet-singlet transitions of metal phthalocyanines; Ruby cathodoluminescence; Stimulated Raman scattering in the pulsed mode; Electrooptical properties of uniaxial crystals; Certain spectral characteristics of three- and four-ligand complexes of europium with beta-diketones; The Faraday effect in silicate glasses with rare-earth ions; Dipole moments of the excited states of indole and tryptophan; Application of luminescence to determine the state of uranium VI; Electronic absorption spectra of hydrogenated quinolines; Luminescence properties of NaI-Tl single crystals; Infrared absorption spectra of organic uranyl nitrate solutions; Infrared absorption spectra and the enolization of certain beta-diketones; Absorption-band intensity in the infrared spectrum of polyethylene; Determination of hydroxyl groups during setting of polyurethanes., Unedited rough draft trans. of Zhurnal Prikladnoi Spektroskopii (USSR) v6 n3 p285-421 1967. See also Volume 6, Number 4, AD-682 060.

The general performance of selected RCA 8575 photomultiplier tube-NaI(T1) scintillator combinations was examined. The measurements were made with NaI(T1) crystals packaged with both glass and quartz windows. The results of the study show that the 8575 is fast, quiet, and shows virtually no internal interaction effects. In addition it was found that the increased light transmission capabilities of the quartz window produced no measurable changes in the measured resolving times. (Author)

Studies were completed of reference electrodes for use in liquid ammonia solutions, and a soft glass-Pyrex separator with microcracks was adapted for use in reference electrodes for pressurized cells. Redox potentials and overvoltage relationships were determined for various cathector and matrix materials in liquid ammonia solutions, the shifts of potentials on the various metals and pyrolytic graphite providing an indication of their relative merit for hardware cell use. Initial study of the S-NH3 system was conducted in neutral solutions with a Pt screen as the cathode, a Pt anode, and a Pb wire reference electrode in a three-compartment cell. Reduction efficiency was twice as great in NaSCN than in NaI ammoniate. Qualitative tests of solubility enhancement indicated that addition of either ethylamine or ethylenediamine to liquid ammoniates increases the solubility of sulfur in neutral solutions. (Author), See also AD-633 957.

The impurity ion O(-) has been introduced into alkali iodide crystals and detected at 4K by EPR spectroscopy. A quantitative understanding of the g factor and 17O hyperfine interaction was obtained with the aid of equations derived in a recent analysis of the analogous S(-) impurity. (Author)

A scattering chamber for inelastic neutron scattering at pressures up to 3000 atm was constructed. This pressure proved to be large enough to induce in some materials phonon frequency shifts of the order of 1% which are measurable by the inelastic neutron scattering technique. Measurements on pressure induced frequency shifts of some phonons in lead and sodium iodide were made. The phonon frequency distribution in the random binary alloy Pt + Cu (5%) was compared with that of a pure Pt sample. Also measured was the change of phonon frequency distribution of very fine MgO powders against that of large-crystalline samples. (Author)

It is shown that a dual crystal/single photomultiplier scintillation detector system in conjunction with a pulse shape discrimination technique can reduce the entire Compton contribution to a gamma-ray spectrum up to 40%.

The present research confirmed that the probable reaction between sodium iodide and 1-bromo-1-nitropropane in acetone is a second order reaction with the rate constant 0.0686 mole min-1 liter-1. The rate determining step is indicated to be formation of the activated complex. [Chemical formula here] Sodium iodide in acetone was added to 1-bromo-1-nitropropane and samples were removed at timed intervals. The reaction was stopped by the addition of water. The halogens present were titrated with a standard silver nitrate solution containing barium nitrate and nitric acid using a Fisher titrimeter. From these data, the rate of replacement was determined and reaction constants determined. The kinetic measurement could not be extended to the completion of the reaction because the formation of free iodine became significant, indicating a possible side reaction or, more correctly, the decomposition of the end product. Consequently constants are based on the initial reaction rates. This worker was not able to identify any product other than the expected 1-iodo-1-nitropropane. However, the infrared spectrum did not show a very weak alkene absorption. Also no evidence of inversion of structure during reaction was found because of difficulty of resolving the d and 1 isomers of 1-iodo-1-nitropropane.

The method for determining the absolute Th-and U-abundances in rocks has been developed by calculating the absolute photpeak efficiency values of 3 in x 3 in and 4 in x 4 in Naldectectors.The efficiency values have been calculated in the y-ray energy region 0.6-3.0 MeV, taking into account self-absorption in the sample. Natural rock samples have been used. In the calculation of the efficiency values the rocks have been considered to be in a pulverised or solid form., The method for determining the absolute Th-and U-abundances in rocks has been developed by calculating the absolute photpeak efficiency values of 3 in x 3 in and 4 in x 4 in Naldectectors.The efficiency values have been calculated in the y-ray energy region 0.6-3.0 MeV, taking into account self-absorption in the sample. Natural rock samples have been used. In the calculation of the efficiency values the rocks have been considered to be in a pulverised or solid form.

There are abundant reserves of Ag-bearing low-grade complex sulphide ores in Yunnan, China, but it is difficult to separate Ag (Zn or Pb) minerals using conventional beneficiation methods. The use was investigated of acid pressure oxidative leaching of a Ag-Pb-Zn ore in a sulphate medium with sodium iodide additions at 90-170 degrees C followed by cyanidation of the solid leach residue. The results showed that Ag and Zn recoveries of 71.5% and 41.29%, respectively, could be achieved under optimum conditions of temperature 130 degrees C, reaction time 120 min, acid/ore ratio 1.4, sodium iodide addition 0.18 g/100 g ore and oxygen pressure 0.7 MPa., There are abundant reserves of Ag-bearing low-grade complex sulphide ores in Yunnan, China, but it is difficult to separate Ag (Zn or Pb) minerals using conventional beneficiation methods. The use was investigated of acid pressure oxidative leaching of a Ag-Pb-Zn ore in a sulphate medium with sodium iodide additions at 90-170 degrees C followed by cyanidation of the solid leach residue. The results showed that Ag and Zn recoveries of 71.5% and 41.29%, respectively, could be achieved under optimum conditions of temperature 130 degrees C, reaction time 120 min, acid/ore ratio 1.4, sodium iodide addition 0.18 g/100 g ore and oxygen pressure 0.7 MPa.