Activated Zinc Sulphide Research Articles

3-D Optical Imaging System of Muon Beams Using a Silver Activated Zinc Sulfide (ZnS(Ag)) Sheet Combined With a Mirror

Optical imaging of muon beams is a promising method for range estimations. However, our previous optical imaging method could only measure 2-D projection images. To measure the beam ranges and widths at any position of the muon beam, 3-D beam images are desired. For this purpose, we developed an optical imaging system using a silver-activated zinc sulfide (ZnS(Ag)) sheet combined with a mirror and a cooled charge-coupled device (CCD) camera. The ZnS(Ag) sheet was set in a black box and irradiated by a positive muon beam at the Japan Proton Accelerator Research Complex (J-PARC). Acrylic plates were used to absorb the muon beam. The measured optical images with different thicknesses of the acrylic plates were stacked and interpolated to create a 3-D optical image, and then the depth and lateral profiles were evaluated. From the depth profile derived from the 3-D image, the Bragg peak position could be estimated. The lateral profiles at the Bragg peak positions could also be derived. We confirmed that 3-D optical imaging was possible using the developed system with a ZnS(Ag) sheet. The system is promising for measuring muon beam distribution, conducting research on muons, and developing future muon radiotherapy.

Optimization of the Alpha Energy Deposited in Radioluminescence Thin Film for Alphaphotovoltaic Application

Activated zinc sulfide (ZnS) is a semiconductor material which able to emit photon in the form of visible light when expose to external energy. The capability of activated ZnS, mainly doped with silver (Ag) and copper (Cu), to convert radiation become light to make it potentially applicable as the radioluminescent thin film for alphaphotovoltaic-type nuclear battery. One of the important specifications of the radioluminescence layer that influences the fluorescence efficiency is the thickness. This work presents a study on the thickness optimization for ZnS:Ag:Cu as the radioluminescent film for alpha particles using Monte Carlo model. Simulation to study alpha particles’ energy deposited by using Stopping and Range of Ions in Matter/TRansport of Ions in Matter (SRIM/TRIM) code. The model examined the transport of 5.485 MeV alpha particles emitted by to determine the best thickness based on energy deposition depth. Based on TRIM module simulation, the optimal thickness for radioluminescence film is approximately 19-22 µm. Most energy from 5.485 MeV alpha particles is deposited in 18.92 µm depth activated zinc sulfide. The results from SRIM/TRIM model then compare with analytical calculation using Bragg-Kleman rule. The alpha particles stop at 22 µm from the SRIM/TRIM simulation while using Bragg-Kleman formula the alpha particles stop at 23.51 µm.

Characterization and radiation detection application of ZnS(Ag) nanoparticles

In this study, pure and transition-metal (silver (Ag)) activated zinc sulfide (ZnS) nanoparticles were prepared using a hydrothermal technique. The particles have spherical shape. The average crystallite size value of ZnS:Ag nanoparticles estimated from the XRD patterns is 4.2 nm. Our results also show that the prepared ZnS has a zinc blende structure. An absorption peak at 350 nm was observed from UV–Vis spectrum for 0.05 mol% Ag doped ZnS which is related to the cubic phase of bulk ZnS. A typical Raman peak of ZnS:Ag crystal at around 346 cm−1 is detected. An optimum activating level of Ag for improved photoluminescence (PL) property is found by measuring the fluorescence of samples. The PL spectra of ZnS:Ag nanoparticles showed a new PL band at 473 nm. Results of ZnS:Ag nanoparticles preparation and optimization, along with structural and optical estimation are discussed and addressed thoroughly. A linear relationship between PMT counts and the flounces of alpha particles has been achieved. The detection efficiency of Lucas cell coated with the prepared samples has been determined.

Study of active surface centers in electroluminescent ZnS:Cu,Cl phosphors

Surface and luminescent properties of copper activated zinc sulfide phosphors were studied. It was shown that measurements of the distribution of active surface centers (DAC) provides a tool of precise study of the surface chemical composition as well as probe for surface structural defects. Correlation between phosphor synthesis and annealing conditions, donor–acceptor properties of its surface and its electroluminescent characteristics was shown.

Stability of tritiated polystyrene coated zinc sulphide phosphor

Copper activated zinc sulphide phosphor was coated with tritiated polystyrene to give self-sustained light sources. The stability of the zinc sulphide phosphor coated with polystyrene was studied. It is suggested that the drastic reduction in light output over a period of two years may be due to the phosphor damage rather than loss of radioactivity.

Preparation of tritiated polystyrene coated radioluminescent phosphor

Soft beta-particles emitted by tritiated polystyrene are impinged upon a copper activated zinc sulphide phosphor to provide self-sustained light sources for nocturnal illumination of watch dials and timepieces, product advertisements, telephone numbers, exit signs etc. For this purpose phenylacetylene was partially reduced with tritium in di-isopropyl ether medium using 10% Pd/CaCO3 poisoned with quinoline to give styrene. Styrene was polymerized to polystyrene by g-radiation (200 kGy dose). The copper activated zinc sulphide phosphor was then coated with that tritiated polystyrene to give self-sustained light sources.

New air density and absolute humidity sensors using optical fibre cableand alpha-rays

A simple sensor for measuring the air density at atmosphericpressure has been developed by the author using common optical fibre cable anda radioactive alpha-ray source. A silver activated zinc sulphide scintillatorfilm and the photomultiplier tube for alpha-ray detection were separated by anoptical fibre cable and the scintillator film was connected with the opticalfibre cable in order to transmit the light caused by alpha-rays. The effect ofthe temperature on the photomultiplier tube could be removed in thetemperature range from 0 to 60 °C. From the relationship betweenthe attenuation of alpha-rays passing through the air and the air density, theair density could be measured with an accuracy of ±4×10-6 g cm-3 in the range from 1.07×10-3 to1.309×10-3 g cm-3. Also, a new-type absolutehygrometer sensor has been devised by coupling the two air density sensors.One of the two is for measuring the dry air density of absolute humidity zeroand the other is for measuring the humid air density. Absolute humidity couldbe measured with an accuracy of ±2 g m-3 in a range of 0to 66 g m-3 by taking into account the differences in countingrates of alpha-rays from the two sensors.

Salient Features in the Preparation of Promethium-147 Activated Zinc Sulphide Phosphor Light Sources

Activation of zinc sulphide phosphor with beta radiation of 147Pm will provide self-sustaining light sources and are widely used as nocturnal illumination devices. Use of 147Pm as energy source is most promising since it forms non-volatile salts. By virtue of this property, it has been precipitated as hydroxide from its aqueous solution for in situ deposition on zinc sulphide phosphor. In this paper, the details of various reaction parameters such as the rate of deposition of 147Pm(OH)3 on ZnS, duration of shaking, specific activity of phosphor and effect of fatty acid (additive) concentration versus luminosity are illustrated with experimental evidence so as to obtain, under optimum conditions, an overall luminosity of 1000 micro lamberts (μlm).

Copper(II) activation and cyanide deactivation of zinc sulphide under mildly alkaline conditions

The adsorption of copper(II) ions onto zinc sulphide particles at pH 9 was determined by inductively coupled plasma atomic emission spectrophotometry and the resulting surfaces were characterised by X-ray photoelectron spectroscopy. The form of the copper(II) activated zinc sulphide surface is controlled by the copper(II) ion concentration and the activation time. Copper(II) activation, at an equivalent surface coverage of one monolayer, results in a copper-substituted zinc sulphide surface, whereas at surface coverages of ten or more equivalent copper(II) monolayers a copper(II) hydroxide surface phase covers the underlying copper-substituted zinc sulphide phases. Mechanisms are proposed which describe copper(II) activation in terms of precipitation, ion-exchange, redox and diffusion processes. Cyanide treatment removes copper hydroxide and copper-substituted species from the surfaces of copper(II) activated zinc sulphide. Ligand exchange mechanisms for cyanide deactivation of copper(II) activated zinc sulphide are proposed.

The interaction of ethyl xanthate with copper(II)-activated zinc sulphide: Kinetic effects

Kinetic studies of ethyl xanthate adsorption onto copper(II)-activated zinc sulphide surfaces were performed by ultraviolet and Fourier transform infrared spectroscopy under flotation related conditions. Copper(II) activation is a prerequisite for ethyl xanthate adsorption on to zinc sulphide. Both the rate of adsorption and the form of the adsorbed ethyl xanthate species are controlled by the activation time and the concentration of copper(II) used. At low copper(II) additions, where copper(II) adsorption shows high affinity behaviour, copper(I) ethyl xanthate is the predominant surface species and the rate and extent of ethyl xanthate adsorption are decreased by extended copper(II) conditioning periods. At high copper(II) additions, where copper(II) is in excess, both diethyl dixanthogen and copper(I) ethyl xanthate can be detected on the zinc sulphide surface. However, their formation is by precipitation from solution rather than via a surface reaction. It is proposed that the penetration of copper ions into the zinc sulphide lattice and the subsequent diffusion back to the solid—aqueous solution interface may be responsible for the time dependence of ethyl xanthate adsorption. X-ray photoelectron spectroscopy depth-profiling by argon ion etching has confirmed that copper ions can penetrate considerable depths into the zinc sulphide lattice and gives credence to the proposed mechanism for the time-dependent adsorption behaviour of ethyl xanthate.

Surface and bulk properties of mechanically activated zinc sulphide

BET, scanning electron microscopy, X-ray photoelectron, infrared, X-ray diffraction and Mossbauer spectroscopy methods were used to identify changes in surface, structural and spectroscopic properties of sphalerite produced by mechanical activation. Activated samples exhibit amorphization of crystallographic structure of the mineral, as well as of hyperfine structure of the accessory manganese. The presence of a new magnetic phase was disclosed in the samples activated for longer periods of time. Changes in structure are accompanied by mechanochemical oxidation of the surface layer of sphalerite.

Surface and bulk properties of mechanically activated zinc sulphide

Surface and bulk properties of mechanically activated zinc sulphide

Spectroscopic studies of the structure of the adsorption layer of thionocarbamate: I. On copper and activated zinc sulfide

The adsorption of O-isobutyl- N-ethoxycarbonylthionocarbamate on copper from aqueous solutions has been studied using various spectroscopic techniques. It was possible to derived structural information about the adsorption layer by combining data collected by infrared reflection-absorption spectroscopy, standard transmission infrared spectroscopy, and X-ray photoelectron spectroscopy. At surface coverages close to monolayer, the thionocarbamate molecules are bound directly to the surface copper atoms through oxygen and sulfur linkages, while their aliphatic chains are headed toward the solution. In the second layer, the molecules are adsorbed on top of the first monolayer with inverse orientation, and they are also bound to copper, forming a 1:1 complex. The spectroscopic data suggest that the copper(I) thionocarbamate complexes formed on copper are six-membered chelates. With further increases in surface coverage, multilayers of copper(I) thionocarbamates are formed with random orientation. The thionocarbamate molecules adsorbed on copper-activated zinc sulfide at nearly monolayer coverage are also oriented with the aliphatic chains toward the solution.

Oxygen-associated luminescence of copper and silver activated zinc sulfide

It was established that the cathodoluminescence centers of the most widely employed activators in ZnS, copper and silver, are localized in the regions of the solid solutions of the system ZnS-ZnO, in which the luminescence of the impurity-free ZnS is observed. It was determined by Alentsev's method that both ZnS-Cu and ZnS-Ag have blue bands which are common to the luminescence bands of the solid solution ZnS-xZnO. The luminescence band of the solid solution ZnS-xZnO belonged to the luminophor obtained by annealing ZnO in moistened hydrogen sulfide at 900 degrees C. Oxygen was present in the luminescence and absorption centers of ZnS activated both by rare-earth activators and by copper and silver. This turned out to be energetically favorable since the centers associated with oxygen were additionally excited by centers responsible for the edge luminescence of ZnS-ZnO.

Developments in electroluminescent panels

In the last decade, the increasing demand for better large area electronic displays has stimulated renewed interest in II–VI compounds. In this review the progress made in producing practical devices will be outlined. A clear distinction will be made between devices that have been demonstrated in the laboratory and those nearing commercial exploitation. The preparation and properties of electroluminescent panels that can be operated under AC and DC excitation will be described. Although originally either powder or thin film structures were considered, more recent developments include composite structures based on powders and thin films. The scope of electroluminescence has also broadened beyond systems based on the copper and/or manganese activated zinc sulphide and selenide to a range of alkaline earth sulphides yielding colours from red to blue. Electroluminescent panels are essentially high field devices. The main problem which had to be overcome before their commercial exploitation was that of maintenance. The life of the panel is dependent on the control of a very narrow high field region over a large area over a long period of time. Comparison will be made between different structures showing how this problem is being overcome. Suggestions can now be made for some defects, such as V S, that may be responsible for the poor maintenance of electroluminescent panels although considerable further analysis is still required for specific identification. It will be shown that a range of electroluminescent panels can now be produced with good brightness and maintenance. The potential of these devices has been considerably enchanced by the production of suitable drive circuits so that large area alphanumeric and graphic displays can now be manufactured.

Electroluminescent Displays

A review is made of the electroluminescent panels that have been prepared using activated zinc sulfide. The materials control at all stages of preparation is stressed. The characteristics of ac, continuous dc and pulsed dc operation cells are compared. Improved maintenance in dc electroluminescent displays is shown in panels prepared from manganese activated zinc sulfide, coated with a conducting layer of copper sulfide. Other activator systems in zinc sulfide are described and possible new host lattices discussed. Red electroluminescence from manganese activated barium zinc sulfide is described.

An Application of Ultra High Speed α Radio-autography in the Detection of 239Pu Skin Surface Contamination

High Speed α-Radioautographic technique, whch was developed by Hsieh et al, was applied to the detection of 239Pu skin surface contamintation to obtain an accurate information as to the contaminated area around the wound.Silver activated zinc sulfide is used as an intensifier in conjunction with high speed Polaroid film. The intensifier film mounted on the double alminum coated myler film is interposed between skin and photographic film. All procedure of above autographic technique was applicable without dark room in routine using special light-tight attachment.About 100dpm 239Pu contamination of skin can expose the shape of contaminated area by several minutes contact by this method.

Infrared Fluorescence in Manganese Activated Zinc Sulphide Phosphors

AbstractA luminescence emission in the 3.00 μm region is reported for manganese activated zinc sulphide phosphors where the manganese concentration is greater than 2%. Optical absorption measurements show a maximum at 0.80 μm with sub‐bands at 0.74 and 0.84 μm, the luminescence being excited by radiation in this region. It is suggested that a new luminescence centre is formed as a result of Mn2+ ions perturbing the host‐lattice.

Investigation on self activated and copper activated zinc sulphide

The diamagnetic susceptibility of zinc sulphide decreases on heat treatment and becomes less temperature dependent. The susceptibilities or the differences in susceptibilities of the pure and activated samples do not obey Curie Law. The susceptibility follows a relation of the typeX T =X 0 +X 1 e −E/KT in which bothX 0 andX 1 have the same sign.X 0 is interpreted as true diamagnetic susceptibility of the sample and gradually increases in value with activation,X 1 depends on the particle size and is found to decrease with the increase in particle size. This is interpreted as being due to surface electrons.“E” as measured in this way is found to be of the order of 0·01 ev. in all cases. Thus“E” seems to be the average surface trap depth of zinc sulphide. It has also been found that in zinc sulphide with low copper concentration the luminescent centres are diamagnetic; copper ions are present presumably in substitutional positions. For zinc sulphide containing high concentration of copper, the presence of paramagnetic centres are detected. It is suggested that in this case copper is present not only at the regular lattice positions acting as luminescent centre but also settles at special lattice sites like dislocation jogs.

�ber den Einflu� der Temperatur auf die Feldverst�rkung und Feldausl�schung der Kathodolumineszenz

The luminescence of manganese activated zinc sulfide has been investigated. It was found that the luminescence, excited by cathode rays, is profoundly influenced by alternating electric fields. At room temperature the emission due to the manganese is enhanced, and that due to selfactivation is quenched by the field. At lower temperatures, however, the direction of the energy transport controlled by the electric field changes the sign: the emission of mangenese is quenched by the field, whereas the luminescence due to selfactivation is enhanced. This behaviour may be explained with reference to our model according to which the electrons gain energy in the electric field and the number of occupied states changes.