Comparison of Makrofol-E and CR-39 as Solid State Nuclear Track Detectors

A comparison of the etching parameters as well as the neutron response for Makrofol-E and CR-39 was considered as solid state nuclear track detectors. The calculated sensitivity for both detectors was compared with the measured one. It is found that CR-39 has higher response to fast neutrons than Makrofol-E. The response increase due to decreasing the rate of layer removed and increasing the etch-pits per unit area.     

Study of Boron Distribution in Germanium Single Crystals grown from the Melt with Solid State Nuclear Track Detectors

To get information about the transport mechanisms of impurities or dopants in the liquid zone for the crucibleless zone melting method of crystal growth the boron distribution was studied in Ge-single crystals using neutron induced autoradiography on solid state nuclear track detectors. The boron distribution found for a cover-free surface of the zone was proved to be caused by non-stationary thermocapillary (Marangoni) convection. The Marangoni convection could be suppressed by a viscous oxide layer on the zone.

Zur Aufklärung der Transportvorgänge von Verunreinigungen oder Dotanden in der schmelzflüssigen Zone beim Verfahren des tiegelfreien Zonenschmelzens der Kristallzüchtung wurde die Bor-Verteilung in Germanium-Einkristallen mittels neutroneninduzierter Autoradiographic mit Festkörperspurdetektoren untersucht. Die bei bedeckungsfreier Schmelzzone gefundene B-Verteilung wird durch eine instationäre thermokapillare (Marangoni-) Konvektion verursacht. Die Marangoni-Konvektion wird durch eine viskose Oxidsrhicht auf der Schmelzzone unterdrückt.     

On Quantitative Autoradiography of Semiconductor Basic Material

It will be described methods of the quantitative evaluation of elements interesting in semiconductor technology and their distribution in silicon using autoradiographic techniques. The local concentration of the element phosphorus in dependence of their local distribution is determined with silver halide films. As standard samples silicon disks phosphorus diffused are used.

The distribution of the element boron and their local concentration is determined on the way of neutron induced autoradiography (NIAR). In this technique boron implanted or diffused silicon disks are used as standard samples. Different possibilities of the quantitative evaluation of autoradiograms will be considered and compared.     

Effect of Annealing Temperature on Track Diameter

In exposing cellulose nitrate CN85 plastic films to alpha particles derived from a ²⁴¹Am source, track diameters were measured with regard to different annealing temperatures. The results have shown that the diameters of the tracks are decreasing when the annealing temperatures are increasing.

Kunstharzfolien aus Zellulosenitrat CN85 wurden einer Alphastrahlung ausgesetzt, die einer ⁴²¹Am-Quelle entstammten. Es wurden die erzeugten Spurendurchmesser im Hinblick auf die Ausheilungstemperatur vermessen und es konnte gefunden widen werden, daβ die Spurendurchmesser mit steigender Ausheilungstemperatur abnehmen.     

The Effects of Storage on CR-39

The effects of storage temperatures on the track registration of CR-39 as a solid state nuclear track detectors have been investigated. The results show that the storage CR-39 detectors cause partial or complete removal of tracks depending on storaged time and temperatures. The bulk activation energy for CR-39 has been found to be 0.883 eV.     

Originalarbeiten: Study of Boron Transport in Plants with a Microradiographic Method

The process of passive transport of borate and tetraborate ions was studied in the root of carrot and in the tuber of potato with a quantitative microradiographic method. The boron concentration profiles developing within the plants were determined after various diffusion times, by utilization of the ¹⁰B(n, α) ⁷Li nuclear reaction. A polycarbonate nuclear track detector registered the ⁷Li nuclei and the alpha-particles. The differential equation of linear diffusion combined with convection was used to describe the concentration profiles within the plants. The diffusion coefficients were determined by means of a computer programme.     

Comparative Study of Depth Dose Distribution of Fast Neutrons Using Solid State Nuclear Track Detectors

A comparative study was made for measuring neutron depth dose distribution in a water phantom by means of different solid state nuclear track detectors. The used detectors were Makrofol, CR-39 and LR-115 with threshold energies of 1 and 0.1 MeV, respectively. Two exposure positions were used, the source in contact with the surface and at 30 cm from the phantom surface. The fluence distribution of ²⁵²Cf as a function of distance in air and in the water phantom were investigated. It was found that the neutron build up factor depends on the irradiation geometry, its values were 1.7 and 1.4 for both exposure positions. These results are in good agreement with the calculated results given in literature. The neutron attenuation and relaxation length had been also determined.     

The Etch-Induction Time T i and Etch-Critical Time T c in CR-39 Plastic Nuclear Track Detector

The etch-induction time, T_c, is measured for α-particles in CR-39 plastic track detector and the etch-critical time, T_c, is calculated for α-particles in CR-39 detector as a function of α-energy, E, and incident angle, 0. The etch-induction time was found to be independent of dip angle and directly proportional to the α-particle energy in the range from 1–6.1 MeV. The etch-critical time was found to be zero for angles greater than the critical angle, 0_c, whereas at angles less than 0_c, the etch-induction time, T_i, was increased by the value of T_c.

Die Induktionsätzzeit T_i wurde für Alpha-Teilchen in einem CR-39 Plast-Kernspurdetektor gemessen und die kritische Ätzzeit T_c wurde für die Alpha-Teilchen als Funktion der Energie und des Einfallswinkels berechnet. Es wurde gefunden, daβ die Induktionsätzzeit unabhängig vom Eintauchwinkel und direkt abhängig von der Teilchenenergie im Bereich von 1 … 6.1 MeV ist. Die kritische Ätzzeit war Null für Winkel, die gröβer als der kritische Winkel 0_c waren, während für Winkel, die kleiner als 0_c waren, die Induktionsätzzeit T_i zunahm bis zum Wert von T_c.     

On the Thermal Stability of Tracks in Plastics and some Uses in Radiography

The eradication of alpha and fission tracks and the selective track discrimination by heat treatment have been studied in cellulose nitrate, cellulose acetate, and polycarbonate sheets. Some applications of the phenomena in alphagraphy and fissionography are presented.     

Alpha Spectrometry by Using CN85 Plastic Track Detectors

In the present study the alpha particle response which is characteristic of cellulose nitrate detectors CN85 was investigated The track diameter as a function of alpha energy was examined. With regard to the spectroscopy of alpha from track radii it was stated that the discrimination of lower alpha energies shows better results than the high energies for the present etching condition.     

Estimation of Ra-224 Content in Egyptian Black Sand by the Can- and Alpha-Autoradiography Techniques using LR-115 Plastic Detectors

Sealed can- and alpha-autoradiography techniques were used to estimate the effective and real contents of Ra-224 respectively in Egyptian black sand samples collected from Rosetta City in the Nile Delta at the North Coast of Egypt. The effective Ra-224 content was found to be 15 ± 3 Bq · kg^?1. From the average chemical composition of the black sand samples, the range-energy relation for the alpha-particles of the thorium series was calculated. Assuming radioactive equilibrium, the real Ra-224 content for samples collected from different regions were found to range from 90 to 900 Bq · kg^?1. As a result, the total emanation power was measured and then used to estimate grain diameter of the black sand. The average mass exhalation rate of the different locations in Rosetta City was also estimated.     

Contribution of Radon Daughters Plated-Out in a Cylindrical Device by Track-Technique

CR-39 plastic nuclear track detector is used to measure the fraction of alpha-particle tracks due to radon daughters activities plated-out on the internal walls of a cylindrical-shaped plastic can. Radium chloride solution is used as a radon source, the exposure time is ranged from 4 hours to 3 days. To assess the percentage of plate-out effect on CR-39 nuclear track detector, two different methods were used. In one experiment, a few circular parallel pairs of CR-39 sheets were hanged in the can device. In the other experiment, the estimation of the plate-out effect has been performed, after exposure to the radon source, by detecting tracks with a second unexposed sheet placed in close contact to the exposed wall and detectors. In the two methods, it was found that the chemically etched tracks related to plated-out activities contribute about 50% of the measured alpha-particles tracks.

Der CR-39 Plast-Kernspurdetektor wurde zur Messung des Anteils an Spuren von Alphateilchen verwendet, die sich von den Radon-Tochterprodukten ergeben und auf den Innenwänden eines zylindrisch gestalteten Plastbehälters abgeschieden haben. Als Radonquelle wurde eine Radiumchlorid-Lösung verwendet und die Expositionszeiten lagen zwischen 4 Stunden und 3 Tagen. Um den Anteil des Abscheidungseffektes in einem CR-39 Spurdetektor zu bestimmen, wurden zwei unterschiedliche Methoden angewendet. In dent einen Versuch wurden einige zylindrische Parallelpaare von CR-39 Folien in den Behälter gehängt. In dent anderen Versuch wurde der Abscheidungseffekt in der Weise ermittelt, daβ nach der Exposition auf die Radonquelle mit einer zweiten nichtexponierten Folie die Spuren bestimmt wurden. Die nichtexponierte Folie war dabei in einem engen Kontakt zur exponierten Wand und den Detektoren. Durch beide Methoden wurde gefunden, daβ die chemiseh geätzten Spuren, die auf die Abscheidimgsaktivitäten züruckgeführt werden können, einen ungefahren Anteil von 50% an den gemessenen Alphateilchenspuren ausmachen.     

Zur Empfindlichkeit von Festkörperspurdetektoren

Es werden verschiedene Festkörperspurdetektor-Materialien hinsichtlich ihrer Empfindlichkeit gegenüber Bestrahlung mit α-Teilchen und zum Teil auch gegenüber Protonen und Deuteronen verglichen. Die speziell für den Einsutz als Festkörperspurdetektor hergestellten Zellulosenitrat-Folien wurden als empfindlichste Detektoren ermittelt.     

Alpha Particle Response of CR-39 Polycarbonated Detector

The alpha particle response which is characteristic of polycarbonate detectors CR-39 has been investigated. The track diameter as a function of alpha energy in the range from 5.1–22.2 MeV was examined. The mean track diameter or size of the tracks are found to be energy dependent which decreases as alpha energy increases with a trend at about 14 MeV alpha energy. With regard to the spectroscopy of alpha from track radii, it was stated that the discrimination of lower alpha energies shows better results than the high energies for the present etching condition.

Es wurde die charakteristische Wirkung von Alpha-Teilchen auf die Polycarbonatdetektoren CR-39 untersucht. Der Spurendurchmesser als Funktion der Alpha-Energie wurde im Energiebereich 5,1… 22,2 MeV verfolgt. Der mittlere Spurendurchmesser oder die Spurengroβe waren energieabhängig und nahmen mit zunehmender Alpha-Energie bei einem Trend von ungefähr 14 Me V ab. In being auf die Spektroskopie von Alpha-Teilchen von den Spurenradien wurde festgestellt, daβeine Unterscheidung von niederen Alpha-Energien bessere Ergebnisse brachte als solche bei hohen Energien für die vorliegende Ätzbedingung.     

固体核径迹探测器的刻度

为了测量在神舟飞船返回舱内由空间重电离粒子引起的辐射剂量，采用了固体核径迹探测器CR-39来测量飞船飞行期间，返回舱内由重电离粒子引起的能量沉积. 本文介绍了CR-39探测器对能量沉积的响应的刻度.     

High Energy Charged Particle Registration in CR-39 Polycarbonated Detector

Track etch rate characteristics of CR-39 plastic detector exposed to ²⁸Si ions of 670 MeV energy have been investigated. Experimental results were obtained in terms of frequency distribution of the track diameter, track density and bulk etching rate. A dependence of the mean track diameter on energy was found. The application of the radiation effect of heavy ions on CR-39 in the field of radiation detection and dosimetry are discussed. Results indicated that it is possible to produce etchable tracks of ²⁸Si in this energy range in CR-39. We also report the etching characteristics of these tracks in the CR-39 detector.     

Designing polymers for nuclear track detection

This article describes our attempts since 1996 to systematically design and synthesize monomers and corresponding polymers for nuclear track detection. So far more than 15 homopolymers/copolymers have been prepared and tested by us for this purpose. Some of these polymers show better track detection characteristics vis-á-vis commercially available poly allyl diglycol carbonate (PADC) track detectors.      

Informationen

Compared are some of the properties of the solid state track detectors (SSTD) on the basis of nitrogen-free cellulose derivatives (cellulose acetate, triacetate and acetobutyrate), cellulose nitrate (LR-115, CN-85) and a CR-39 track detector. The optimum composition of the cellulose acetobutyrate has been established which will ensure the best mechanical properties. A simple device has been used to measure the α detection effectiveness over the energy range from 0 to 1.2 MeV of the cellulose acetobutyrate detectors in an electric field or under UV radiation or after catalytic etching. The proton detection effectiveness of the CN-85 detector has been measured. Also presented are the track autoradiograms of the distribution of B, Li, N and ³He in silicon, silicon carbide and steel.     

Measurements of Environmental Radon-222 Concentrations in Indoors and Outdoors in Egypt

The major contribution to population exposure from natural radiation arises from the inhalation of the decay products of radon. Substantial surveys are being conducted by several investigators to estimate the indoor and outdoor exposure nationally and to discover regional variations. In this work, radon concentration in the indoor and outdoor air was determined using the can technique and employing CR-39 solid state nuclear track detector for lengthy exposures. The range of radon-222 activity in this survey was 54 … 299 pCi · m^?3 in Cairo, 22 … 171 pCi · m^?3 in Alexandria and 89 … 370 pCi · m^?3 in Asiut. Measurements carried out in Aswan and Sinai ranged between 98 … 411 pCi · m^?3. Values of indoors and outdoors radon concentrations were found to vary with geographic location, season and height above ground. Further work is going on to study the different parameters affecting the levels of the environmental radon.     

Anwendung von Radionukliden in der Elektrotechnik

The effect of etching conditions on the energy resolution was studied. In the present work cellulose nitrate CN-85 films were used as Solid State Nuclear Track Detectors. There exists a relation between the etching condition and the energy resolution.