Radiography with Solid State Nuclear Track Detectors

The investigation of localisation is counted among the typical and important applications of nuclear track recorders. In this paper, after a comparison of the most important features of nuclear track recorders a system of their applications is given. On the grounds of information obtained from the tracks, eight groups of applications can be distinguished. One of them represents the four geometrical situations of the different types of radiography.

Taking radiography into account in the wider sense, as an investigation of localisation, then several cases of special localization tasks are known, which can be classified into two further groups of applications of track detectors. A survey of the applications of solid slate nuclear track detectors for all kinds of radiography is given on the basis of this definition of localisation experiments.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

ESR Induced in CR-39 Plastic as a means of Gamma Ray Dosimetry

The gamma-induced ESR in CR-39 plastic has been studied and the possibility of using it as a gamma-ray dosimeter was investigated. The induced ESR was found to vary linearly with the dose up to 700 krad. The fading of the induced ESR signal at room temperature has been also investigated. The results suggest the possible use of CR-39 plastic for gamma dosimetry in the range 0 … 700 krad.

Es wurde die γ-induzierte ESR-Technik am CR-39 Plast untersucht und ihre Eignung als Gammastrahlen-Dosimeter geprüft. Die induzierte ESR variierte linear bis zu einer Dosis von 700 krad. Das Fading des induzierten ESR-Signals bei Zimmertemperatur wurde ebenfalls untersucht. Die Ergebnisse zeigten, daβ cine Verwendung des CR-39 Plast als Dosimeter für Gammastrahlen im Bereich von 0 … 700 krad möglich ist.     

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.     

FT-IR spectroscopy of carbon dioxide in CR-39 and SR-90 track detectors irradiated with ions and gamma-rays at different energies and fluences

Two types of polymeric track detectors CR-39 and SR-90 were irradiated with protons, alpha particles, heavy ions and gamma-rays at different energies and fluences. After irradiation these detectors were analyzed with an FT-IR spectrometer of Jasco type 5300 in transmission and ATR modes. We have found that CO₂ is produced not only by irradiation but also by polymerization. The amount of CO₂ in the detector material is closely related to the latent track formation.     

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.     

Track structure in polyethylene terephthalate irradiated by heavy ions: Let dependence of track diameter

The structure of latent tracks in polyethylene terephthalate is studied using chemical etching combined with a conductometric technique. Geometrical parameters of the latent tracks for the range of the electronic energy loss (dE/dx) between 3 to 24 keV/nm are estimated. The dependence of the track core and track halo size on the energy loss is analyzed.     

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.     

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.     

Nuclear tracks: present and future perspectives

Current research work related to the development of nuclear tracks comprising: (i) fundamental principles (nuclear track physics and chemistry, as well as development of track detectors and the relevant hard- and software), (ii) development of nuclear instruments and methods (etch track radiometers for ions, neutrons and cosmic rays, radon monitoring devices, radiography and fission track dating) is briefly outlined. The paper concentrates on a literature survey of applications of nuclear tracks in (iii) physical sciences (high-energy physics, nuclear physics and earth sciences), (iv) biomedical sciences (radiation protection, environment, cancer therapy), and (v) technological sciences (materials, nano-technology and nuclear technology).

Presently about 350 papers per year are being published in this field. Increased activity is noted in ion track technology (track-made membranes, modern nano-tech methodology including biological and biological-like samples, nano-electrode bio-electrochemistry, bio-magnetic assays and probes). New applications of nuclear tracks in fundamental (possibility of the detection of neutron quantum states in a gravitational field, nucleus–nucleus interactions, search for new chemical super-heavy elements) and applied science (precise measurements of the behaviour of radiation in human tissue in connection with of long term space missions and treatment of cancer) are surveyed, and possible research in the next decades is presented and examined in this review paper.     

Influence of external and internal conditions of detector sample treatment on the particle registration sensitivity of Solid State Nuclear Track Detectors of type CR-39

The sensitivity of charged particle registration with SSNTD is the most important parameter to decide about the applicability of those detectors in research, technology and environmental dosimetry. The sensitivity is strongly influenced by the treatment of detector samples before, during and after the exposure and the final evaluation process by chemical etching. Whereas changes in detection properties by external environmental influences are generally considered, the dependences on the etching conditions are ignored. Commonly the sensitivity is assumed to compensate variations in the etching conditions for track revealing. In the present work the validity of this hypothesis will be checked. In the frame of the existing database the sensitivity is not really independent on variations in etching temperatures and should be corrected for differences in the activation energies for stimulation of the bulk and track etching process. Differences in the concentration dependence may be of minor importance. Furthermore, the registration sensitivity depends on environmental conditions before, during and after the irradiation with particles under investigation. Such external parameters are the air pressure, the sample temperature and modification of bulk material by out-gassing in vacuum and exposure to γ-rays. However, the available database is insufficient and inaccurate to draw final conclusions on the detection properties of SSNTD under various external and internal conditions.     

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.     

Particularization of alpha contamination using CR-39 track detectors

Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in environmental experiments. The measurement of alpha activity on sources in an environment, such as air is not easy because of short penetration range of alpha particles. Furthermore, measurement of alpha activity by most gas ionization detectors suffers from high background induced by the accompanying gamma radiation. Solid state nuclear track detectors (SSNTDs) have been used successfully as detecting devices and as a passive system to detect alpha contamination on different surfaces. This work presents the response of CR-39 (for two types) to alpha particles from two sources, ²³⁸Pu with energy 5 MeV and ²⁴¹Am with energy 5.4 MeV. The methods of etching and counting are investigated, along with the achievable linearity, efficiency and reproducibility. The sensitivity to low activity and energy resolution are studied.      

Comparative analysis of CR-39 sensitivity for different sets of measurable track parameters

In the present paper the sensitivity V of plastic nuclear track detectors CR-39 to the space radiation, accelerated heavy ions in wide LET range and α-particles is studied. Different approaches for V evaluation are considered and compared. Main attention is given to the method that is appropriate for the measurement of short range heavy secondaries of space radiation. Finally, the experimental verification of the designed V function is carried out via simulation of the secondaries with low energy α-particles in the vicinity of the Bragg peak.