Cellulose Nitrate Detectors Research Articles

Study of 168O ion tracks in cellulose nitrate plastic detectors

Cellulose nitrate (CN) plastic track detectors exposed to 8.75 MeV/n 16 8O ions have been obtained from JINR, Dubna, USSR. The bulk etch rate of CN detectors and the track etch rate of 16 8O ions in this detector have been measured for different temperatures. From the data the activation energy for bulk etching and track etching are calculated. The range of 16 8O ions in a CN detector is determined by measuring the track length. The maximum etched track length agrees with the theoretically computed range as well as with those reported by earlier workers. From the response curve the ‘critical energy loss’ (d E/d x) c has been determined for this detector material.

Blocking measurement of a relatively long lifetime:Si2812.073 MeV level

Axial blocking of $\ensuremath{\alpha}$ particles from the $^{27}\mathrm{Al}(p, {\ensuremath{\alpha}}_{0})$ resonance at ${E}_{p}=504.9$ keV has been used to measure the "long lifetime" of the $^{28}\mathrm{Si}$ 12.073 MeV level by projecting the effective mean displacement to a "short lifetime" value. The resulting value for $\ensuremath{\tau}={750}_{\ensuremath{-}180}^{+220}$ as has allowed us to study the behavior of the method in the limiting case of mean displacement comparable with the interstring distance.NUCLEAR REACTIONS $^{27}\mathrm{Al}(p, {\ensuremath{\alpha}}_{0})^{24}\mathrm{Mg}$, $E=0.505$ MeV; measured resonance yield and blocking effect for different mean transverse displacements. $^{28}\mathrm{Si}$ deduced level width. Single crystal thick Al target. LR 115 cellulose nitrate detectors.

Spark Counting of Tracks Directly Induced by Fast Neutrons in Cellulose Nitrate Detector

Studies are described on spark counting of tracks directly induced by fast neutrons in the cellulose nitrate detector, LR-115 (Type H). The spark counting for the detector irradiated by neutrons from an Am-Be source was performed under different etching conditions and different sample setting in the spark counter used in the experiment. The characteristic curves of spark counts vs. neutron fluence was determined, and sensitivity of the detector treated by the method was obtained to be 3 × 107 for the fluence between 1 × 107 and 2×109 n/cm2 in the most adequate condition. The reproducibility of this method was estimated to be 13%.

Spark counting of tracks directly induced by fast neutrons in cellulose nitrate detector.

Studies are described on spark counting of tracks directly induced by fast neutrons in the cellulose nitrate detector, LR-115 (Type H). The spark counting for the detector irradiated by neutrons from an Am-Be source was performed under different etching conditions and different sample setting in the spark counter used in the experiment. The characteristic curves of spark counts vs. neutron fluence was determined, and sensitivity of the detector treated by the method was obtained to be 3 × 107 for the fluence between 1 × 107 and 2×109 n/cm2 in the most adequate condition. The reproducibility of this method was estimated to be 13%.

On the electrochemical etching of nuclear particle tracks in cellulose nitrate films using 50 Hz high voltage power supply

The treeing phenomenon observed in electrochemical etching (ECE) of Daicel cellulose nitrate detectors is described. A perspex filter chimney as cell and a 50 Hz high voltage unit for power supply constituted the simple ECE system. It was possible to initiate treeing in the Daicel detector leading to an enlargement of track ends to about 10 μm in diameter with significant clarity against the background. Various attempts to augment the treeing process and the results obtained so far have been reported.

Dosimetry of high fast neutron fluxes

The cellulose nitrate detector Kodak LR 115 is applied as a dosimeter for high fluxes of fast neutrons. The dose is determined by the light transmission through etched neutron induced tracks.

Thermal effects on the bulk luminous transmittance and track recording characteristics of dyed cellulose nitrate detectors

Simple heat treatment of polymers produces various typical morphological and chemical changes which consequently alter their physical and track registration properties. Bulk colour fading and alpha-track annealing effects have been studied in Kodak Pathé red-dyed cellulose nitrate film LR-115, type II and another Kodak product CA80-15, lightly rose-tinted cellulose nitrate, as a result of thermal annealing (room temperature to 155°C for times of 30 min to 16 h). The degree of colour fading has been measured in terms of percentage transmission of ordinary white light as sensed by a cadmium sulphide photoconductive cell, imitating the response of the human eye. It is found that at a given temperature, the transmittance rises first and acquires near-saturation after a certain annealing time. In the measurements reported here, it is seen that near-saturation transmittance is approximately proportional to the square root of the product of annealing time and temperature. The possibility of using these colour fading and transmittance measurements as an index of latent track fading is described.

Nuclear track registration from solution media: Alpha track registration in solid state track detectors in solutions of actinides

The results are reported of a study on various aspects of registration and revelation of alpha tracks in the three most commonly used cellulose nitrate detectors (namely LR 115, Ca 80-15 and Daicel) immersed in solutions of actinide elements. Americium, plutonium and enriched uanium in dilute nitric acid solution were used as alpha sources. Experimentally determined values of K wet (a measure of the efficiency of track registration from solution) are around 2–5×10 −4 cm for the three detectors under various conditions of exposure and etching. These values have been examined in the context of the range of the particle, its energy loss rate in the solution medium and the sensitivity of the detectors. Optimum conditions of track registration and revelation for the analytical applications of the technique have been experimentally established. Linear relationships were obtained between the concentrations of uranium or plutonium in the solution and the number of tracks per cm 2 obtained under uniform experimental conditions of exposure and etching.

Axial blocking measurement of theSi2812.291 MeV level width

The width of the 12.291 MeV level of $^{28}\mathrm{Si}$ was measured by the axial blocking of $\ensuremath{\alpha}$ particles from the $^{27}\mathrm{Al}$($p$,${\ensuremath{\alpha}}_{0}$) resonance at ${E}_{p}=731.4$ keV. The result $\ensuremath{\Gamma}={28}_{\ensuremath{-}6}^{+13}$ eV compares very favorably with that obtained from yield measurements but not with a previous planar blocking experiment.NUCLEAR REACTIONS $^{27}\mathrm{Al}$($p$,${\ensuremath{\alpha}}_{0}$)$^{24}\mathrm{Mg}$, $E=0.731$ MeV; measured blocking effect. $^{28}\mathrm{Si}$ deduced level width. Single crystal thick Al targets. LR 115 cellulose nitrate detectors.

Track radiography of heavy-ion induced sputtering

To study heavy-ion induced sputter phenomena, several glasses of different chemical composition were irradiated with 56Fe +-ions in the energy of 70.5–100 keV at the GSI-UNILAC, Darmstadt. A sensitive particle track technique was employed to measure differential sputter yields and the angular distribution of sputtered atoms in 2π-geometry. This techniques utilizes U, Th, Li and B contained in the target matrix as tracer elements. The sputtered target atoms are collected on a cone-shaped catcher (Makrofol polycarbonate or Teflon foil) and the target atoms are recorded via ( n, f) and ( n, ƒ) reactions as particle-track radiographs of the catcher on mica or CA 80-15 cellulose nitrate detectors. The cone shape of the catcher foils allows one to scan the sputtering process in 2π-geometry in a single irradiation experiment. The detection sensitivity for sputtered atoms is estimated to be <5×10 11 target atoms cm −2 in the case phosphate glass containing 0.06% 235U and <10 13 target atoms cm -2 in the case Li 2B 4O 7 glass. Angular distributions for U-phosphate and Li 2B 4O 7 glass sputtered by 100 keV 56Fe +-ions are presented.

On improvement of charge resolution of cosmic ray particles using a cellulose nitrate plastic detector

By employing improved procedures of measurement and analysis we have been able to obtain good charge resolution for stopping cosmic ray nuclei with Z⩽30 in a cellulose nitrate detector. In a particular, it has been found that ( V t V b ) provides a much more reliable measure of ionisation loss than cone length. A charge resolution of 0.2 charge units for nuclei with Z≲20 and of 0.3 charge units for nuclei with Z > 20 has been achieved in the present experiment.

Lifetime of the 937- and 885-keV resonances in theAl27(p,α) reaction

We have used the crystal blocking technique to measure the lifetimes of $^{28}\mathrm{Si}$ compound states excited by the $^{27}\mathrm{Al}$ ($p$,$\ensuremath{\alpha}$) reaction at ${E}_{p}=937 \mathrm{and} 885$ keV. Axial blocking on the $〈110〉$ axis of thick Al crystals and Kodak LR 115 plastic detectors are used. Measurements have been made at a 0.2 \ensuremath{\mu}m depth. A study is made of the yields of some ($p$,$\ensuremath{\alpha}$) resonances on Al and of the depth dependence of blocking dips. The data are analyzed by comparison with a realistic Monte Carlo model. The resulting lifetime, ${\ensuremath{\tau}}_{937}&lt;17$ as (as = ${10}^{\ensuremath{-}18}$ s) and ${\ensuremath{\tau}}_{885}={38}_{\ensuremath{-}9}^{+10}$ as are compared with previous work.NUCLEAR REACTIONS $^{27}\mathrm{Al}$($p$,$\ensuremath{\alpha}$)$^{24}\mathrm{Mg}$, $E=0.731\ensuremath{-}1.183$ MeV; measured yields in thin targets. LR 115 cellulose nitrate detectors. $E=0.885, 0.937$ MeV; measured blocking effect. $^{28}\mathrm{Si}$ deduced mean lifetime. Single crystal thick Al targets.

Nuclear track registration in solid state track detectors immersed in solutions: Determination of boron in complex matrices

The registration characteristics of charged particle tracks from the reaction 10B(n, 4He) 7Li in cellulose nitrate plastics immersed in boron containing solutions have been studied, in close analogy to fission track registration in detectors immersed in fissile material solutions. The combined track registration efficiency factor, K wet, due to 4He and 7Li recoils in solutions has been evaluated for the three most commonly used cellulose nitrate detectors Daicel, CA 80-15 and LR-115. The values are (2.20±0.05)×10 −4 cm, (2.25±0.02)×10 −4 cm and (3.45±0.03)×10 −4 cm respectively for the three detectors. The use of this solution technique in the determination of low concentrations (ppm range) of boron in different matrices and in the presence of uranium is studied in detail and the various factors such as the effect of competing reactions like 17O(n, 4He) 14C etc. which affect the accuracy are discussed. The usefulness of this technique in other allied fields such as thermal neutron dosimetry is suggested.

Confirmation of Track Formation in Cellulose Nitrate Detector by Lithium Particles from10B(n, α)7Li Reaction

Confirmation of Track Formation in Cellulose Nitrate Detector by Lithium Particles from¹⁰B(<i>n</i>, α)⁷Li Reaction

The effect of pre-irradiation thermal treatment on the track revealing properties of a CN track detector

The influence of a pre-irradiation thermal treatment on such properties as solvent removal, bulk etch rate, etch delay time and sensitivity has been investigated for cellulose nitrate (CN) detectors. It has been found that the duration of the thermal pre-treatment has a remarkable effect on the transparency of the etched detector sheets.

Application of the cellulose nitrate detector for the simultaneous study of 6Li(d, α) 4He and 6Li(d, p) 7Li reactions

A method has been developed for the simultaneous determination of the angular distributions of α-particles and protons from the 6Li(d, α) 4He and 6Li(d, p) 7Li reactions at bombarding energies below 180 keV applying CA 80-15 cellulose nitrate solid-state nuclear-track detector (SSNTD). Both reactions have potential applications in the controlled thermonuclear research (CTR). Cross-section data are also presented and comparison is made with previously reported results between 100 and 180 keV deuteron energies.

Confirmation of Track Formation in Cellulose Nitrate Detector by Lithium Particles from 10B(n, α)7Li Reaction

Two experiments were performed, which confirmed that the lithium particles produced by the 10B(n, α)7Li reactions form etchable latent tracks in cellulose nitrate resin. The first experiment was made on a pair of resin detector plates sandwiching between them a boron-bearing layer. Upon irradiation and etching, the tracks appearing on the two plates were found to constitute matching pairs, some of which appeared to be shorter than others, suggesting their correspondence respectively to the 7Li and α particles generated by the 10B(n, α)7Li reaction. This surmise was further confirmed by a second experiment, in which the pairing of etch-pits was examined between the two faces of a film detector of thickness below the range of a but above that of 7Li particles. The ratio between paired and single etch-pits counted in a unit area of the two faces of film after irradiation and etching proved to be quite close to the value derived by calculation based on the assumption that 7Li as well as α particles leave etch...

The measurement of radon and thoron by solid state nuclear track detectors

Abstract Experiments have been conducted to study (a) the development and annealing properties of the latent damage trails produced by radon/thoron alpha particles in plastic Solid State Nuclear Track Detectors (SSNTDs), and (b) the diffusion properties of radon and thoron in various media by using SSNTDs. The information thus obtained has been employed for (a) the optimization of the conditions for the construction of radon/thoron dosimeters for uranium/thorium mines, and (b) the use of SSNTDs for prospection and estimation of uranium and thorium. The results indicate that these gases can diffuse even through rocks, and cellulose nitrate detectors, LR-115 and CA80–15, can be profitably employed in dosimetry, prospection, and for the discrimination between uranium and thorium deposits.

Some aspects of the etching behavior of cellulose nitrate as track detector

Experimental results are presented to support the hypothesis that the etching velocity in cellulose nitrate detectors is dependent on the local water content of the foil. The consequence is drawn that high concentrations (>4.7 N) of the etching solution should not be used for high precision track etching. The possibility to vary the V t/ V b ratio is reported to have a useful application in biological experiments. Further an influence of etch products at low NaOH concentrations was found. Materials. The cellulose nitrate detectors used in this investigation are 250 μm sheets made by Daicel, Nippon (plasticized) and 100 μm sheets made by Kodak, France (Type CA 80-15, plasticized). No qualitative difference in the etching behavior of these two materials was obtained regarding the reported investigations, although the differences are partly large regarding other features.

Radon and thoron dosimetry by plastic solid state nuclear track detectors

Studies have been made concerning (a) the development and annealing properties of the latent damage trails produced by radon/thoron alpha particles in plastic solid state nuclear track detectors (SSNTDs), and (b) the diffusion properties of radon and thoron in various media by using SSNTDs. The information thus obtained has been employed for (a) the optimization of the conditions for the construction of radon/thoron dosimeters for uranium/thorium mines, and (b) the use of SSNTDs for the prospection and estimation of uranium and thorium. The results indicate that cellulose nitrate detectors, LR-115 and CA80-15, can be profitably employed in dosimetry, prospection, and for the discrimination between uranium and thorium ore bodies.