Comparison of responses of CR-39, PM-355, and CN track detectors to energetic hydrogen-, helium-, nitrogen-, and oxygen-ions

Samples made of the CR-39 and PM-355 plastic nuclear track detectors (NTDs) as well as of the CN films were irradiated with quasi-monoenergetic beams of protons, alphas, N⁺-, and O⁺-ions produced by various accelerators. For different samples an energy value of the particle beams was changed from several hundreds keV to 3 or 4.5 MeV. After irradiation the detector samples were etched chemically under controlled conditions during periods lasting from 2 hrs to 20 hrs. Every 2 hrs track diameters were measured by means of an optical microscope. Differences in the crater diameters in the detectors etched in steps, and those etched continously, have been found to be smaller than 10 percent. The paper results detailed calibration diagrams showing a dependence of track diameters on the ion energy value for different etching times.     

Calibration of PM-355 nuclear track detectors; comparison of track diameter diagrams with track depth characteristics

The calibration diagrams, i.e. track diameters and track depths versus ion energy and etching time, as obtained for PM-355 track detector irradiated with He-ions are presented. The both detector characteristics are compared. The track etch rate is determined by two methods, as a function of the etch pit depth and the ion energy loss.     

Influence of intensive γ and electron radiation on tracks formation in the PM-355 detectors

Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in plasma experiments. The track detectors used in the fusion-oriented experiments encounter “harsh” conditions (intense X-ray and neutron radiation, heat impact, shock waves and plasma fluxes). Therefore, such detectors should be tested under similar conditions. This paper concerns influence of electron and γ radiation on the track formation in PM-355 detectors. Samples were irradiated with 1.5-MeV protons and ⁴He-ions, and with 5.5 MeV particles. After that they were exposed to γ and electron radiation. Irradiation doses were varied from 100 kGy up to 2000 kGy. The etching was performed in steps, and a bulk etching rate (V_B) was determined versus an absorbed dose of electron and gamma radiation.     

Influence of intense soft X-ray radiation on the parameters of tracks induced in CR-39 and PM-355 solid state nuclear track detectors

This paper presents the results of the influence of soft X-ray radiation on craters induced in SSNTDs by energetic α particles and protons of energy in the MeV range. We checked two detectors of the PM-355 and CR-39 types in order to verify and compare their resistance to the harsh conditions of high-temperature plasma experiments. To determine this effect some detector samples were first irradiated with α particles emitted from natural α particle sources and protons delivered by a particle accelerator. After that these samples were exposed to soft X ray radiation emitted from an X ray tube and also from the PF-1000 Plasma Focus facility. Doses during X ray irradiations varied from 0 up to tens of kGy. The irradiated samples were then etched in steps and track diameters were determined versus the absorbed dose and etching time and compared with those measured in samples not exposed to X ray radiation.     

Advantage of PM-355 nuclear track detector in light-ion registration and high-temperature plasma diagnostics

Detailed calibration studies of selected types of SSNTDs have been performed at the SINS using monoenergetic light ions of energy within MeV range. These studies were motivated by the application of such detectors in the optimal way for plasma physics experiments. This paper shows track diameter evolutions versus particle energy and etching time. Some conclusions related to track registration phenomenon and detection properties of the investigated detectors, especially of the PM-355 type are also presented.     

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.     

Changes induced in structure and optical properties of PM-355 nuclear track detector due to laser irradiation

PM-355 is a class of polymeric solid-state nuclear track detectors which has a lot of applications in several radiation detection fields. Samples from sheets of PM-355 have been exposed to infrared (IR) laser fluences ranging from 1 to 12.8?J/cm². The effect of IR laser radiation on the structural properties of PM-355 has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy. The results indicate that the samples exhibit chain scission under the effect of laser irradiation up to 4.2?J/cm², thus producing free radicals that led to the formation of new bonds started and continued until 12.8?J/cm². This reduces the ordering structure, giving the PM-355 polymer more resilience. In addition, the laser irradiation at the fluence range 4.2–12.8?J/cm² led to a more compact structure of PM-355, which resulted in an improvement in its isotropic nature with an increase in Vickers hardness and refractive index. Further, the color changes due to laser irradiation were computed using the transmission data in the wavelength range of 370–780?nm. It is found that the color intensity, which is the color difference between the irradiated samples and the non-irradiated one, increases with increasing the laser fluence, largely depending on the proportions of the blue color component.     

X-ray irradiation-induced structural modifications in PM-355 polymeric nuclear track detector film

Samples from sheets of the polymeric material PM-355 have been exposed to X-rays from a 50 kV X-ray tube in the dose range of 10–300 kGy. The resultant effect of X-ray irradiation on the structural properties of PM-355 has been investigated using different techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Vickers hardness and refractive index measurements. The results indicate that the X-ray irradiation of PM-355 in the dose range of 10–20 kGy causes initially chain scission. Above 20 and up to 100 kGy, the active free radicals produced from scission contribute to chemical reactions that lead to the crosslinking. Thus, the X-ray irradiation in the dose range of 20–100 kGy leads to a more compact structure of the PM-355 polymer, resulting in an enhancement of its Vickers hardness and refractive index. Moreover, the irradiation in the dose range of 100–300 kGy leads to the predominance of the degradation. This degradation is reported by FTIR spectroscopy and enhances the degree of ordering in the degraded samples as revealed by XRD technique. Additionally, it decreases both the Vickers hardness and refractive index of the PM-355 samples.     

Application of CR-39 track detectors for corpuscular diagnostics of high-temperature plasmas

Solid State Nuclear Track Detectors (SSNTDs) have been used for corpuscular diagnostic in numerous high-temperature plasma experiments. This paper presents different applications of the detectors mentioned above, particularly in nuclear fusion investigations. Some new projects and proposals of the use of such detectors in large-scale plasma experiments, e.g. tokamaks, and laser-fusion facilities are demonstrated. To use the SSNTDs in the optimal way and to determine their detection characteristics, detailed calibration studies of the selected plastic detectors (CR-39, PM-355, PM-500, PM-600) have been performed at IPJ for several years. To carry out calibration measurements of these detectors, ion beams from different accelerators were applied. The paper presents detection characteristics, i.e. track dimensions as a function of ion energy, atomic number and etching time.     

Study of spatial structure and energy spectrum of ion beams by means of LR 115A and PM-355 nuclear track detectors

The paper reports on measurements of pulsed plasma-ion streams, as performed with the selected solid-state nuclear track detectors (SSNTD). The ion-beams were produced by an experimental device (RPI-IBIS) equipped with coaxial electrodes (each made of molybdenum rods) and a fast-acting gas valve. The device was operated at 30 kV/44 kJ, with puffing of pure hydrogen or deuterium. The spatial structure of the ion beams was studied with pinhole cameras equipped with replaceable detectors, and ion mass- and energy-spectra were measured with a Thomson spectrometer. To analyse low-energy ions (below the energy thresholds of LR 115A and PM-355 SSNTD) an additional accelerating system was applied. It was observed that ions of energy are emitted in bunches, and the ion flux amounts to at a distance of 30 cm from the electrodes outlet. Energy spectra of protons and deuterons ranged from about 30 keV to about 400 keV. The ion distributions, as recorded by means of the PM-355 and LR 115A detectors, are similar.     

Comparison of responses of CR-39 and PM-355 track detectors to fast protons, deuterons and He ions within energy range 0.2–4.5 MeV

The paper presents new results of the calibration of the standard CR-39 and super-grade PM-355 plastic detectors, which are applicable for the registration of the protons, deuterons, and ⁴He-ions. The calibration diagram show track diameters vs particle energy for different etching times.     

Tracks of He and S ions with different energies in the PM-355 SSNTDs. Scanning electron microscopy investigations

The Solid State Nuclear Track Detectors PM-355 type were irradiated with helium and sulphur ions with different energies. To develop ion tracks the PM-355 detectors have been chemically etched under the standard conditions. Scanning electron microscopy (SEM) technique was used for observation of surfaces and fractures for determination of diameter and depth of the developed tracks. Shapes of the tracks induced by the projectiles are also presented.     

Physical changes associated with gamma doses of PM-555 solid-state nuclear track detector

The effect of gamma irradiation on the electrical, molecular and structural properties of copolymers of methacrylic esters and olefins, PM-555 solid-state nuclear track detector was investigated. DC conductivity measurements were studied in the temperature range 293–$\text{417}\text{K}$ using solid-state samples of the PM-555 polymer. These samples were irradiated with gamma doses in the range 5–$\text{63}\text{kGy}$. Furthermore, the activation energy was measured, at various temperatures, as a function of the gamma dose. It was found that many changes in electrical resistance of PM-555 polymer could be produced by gamma irradiation via the degradation mechanism. Also, the gamma dose gives an advantage for the increasing correlation between the DC conductivity and the number and mobility of the charge carriers created by the ionizing effect of gamma radiation. Moreover, solutions of different loadings (0.2%, 0.4%, 0.6% and 0.8%) were prepared from the irradiated and non irradiated sheets using pure chloroform as a solvent. The effect of both temperature and gamma dose on the intrinsic viscosity of the liquid samples, as a measure of the mean molecular mass of the PM-555 polymer, were studied. In addition, structural and optical property studies using X-ray diffraction and refractive index measurements were performed on all irradiated and non irradiated PM-555 samples. The results indicate that both the degree of ordering or disordering and the anisotropic character of the PM-555 polymer are dependent on the gamma dose.     

Calibration studies and the application of nuclear track detectors to the detection of charged particles

This paper describes calibration studies of solid state nuclear track detectors (SSNTDs) of he CR-39/PM-355 type. A dozen or so PM-355 detector samples were cut out from detector sheets delivered at different times and were irradiated with mono-energetic protons, deurerons and helium ions of energy ranging up to a few MeV. After that, the samples were etched and track opening diameters were determined as a function of particle energy and detector etching time. These studies were motivated by the application of the detectors in fusion experiments to measure energetic ions which escape high-temperature plasmas. The calibration diagrams obtained enable us to compare the relative sensitivities of detectors from different batches and to use these detectors in an optimal way.     

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.     

Simulation of the track growth and determining the track parameters

We have found the equation of the etch pit wall in solid state nuclear track detectors, as follows:

where: x is the distance along a track from the point where the particle entered the detector; V(x) is the ratio of the track etch rate to the bulk etch rate; C is the integration constant that can be determined from particle penetration depth, and y is the normal distance from the particle trajectory to the etch pit wall. The equation is derived assuming the increasing track etch rate V_t along the particle trajectory.

The above equation can be used for the simulation of the track growth and calculating the major and the minor axis of the etch pit opening. The corresponding computer program was set up. The input parameters of this program are: alpha particle energy, incidence angle and removed layer: the output are track parameters. The results obtained by this method are compared with another approach given by Somogyi and Szalay (1973) and reasonably good agreement is found.     

Heavy-ion particle spectrometry by track pattern in muscovite detectors

Muscovite mica detectors were irradiated with the ions: ¹⁹F of 47.5 MeV, ²⁴Mg of 57 MeV, ²⁸Si of 28 and 74 MeV, ³²S of 32 and 74 MeV, ⁶³Cu of 78.75 MeV and with neutron induced uranium fission fragments. Using optical microscopy, after an appropriate chemical etching, two characteristic etched track structure patterns were observed: a rhombic pyramid terrace structure for the Mg, Si and S ions, and a rhombic prism structure for the Cu ions and fission fragments. The use of these etched track patterns to discriminate two groups of ions between them, for the energy range covered in this work, is proposed.     

Trapped heavy ions on LDEF

Plastic nuclear track detectors were used to study below-cutoff heavy ions in a 28.5 degree inclination orbit aboard the NASA satellite Long Duration Exposure Facility (LDEF). Particle arrival directions and energy spectra were measured in stacks of CR-39 and cellulose nitrate. The obtained results for particles with energies below 50 MeV/nuc are interpreted as evidence for the detection of a trapped component registered in the South Atlantic region at values of L = 1.4−1.7.     

Energy loss dependent transversal etching rates of heavy ion tracks in plastic

By the method of electrolytical etching track etching rates V_t and corresponding transversal track etching rates V_trans of single heavy ion tracks in thin Makrofol KG foils have been measured at ion energies from 10–480 MeV/u. Makrofol KG foils of 8 μm thickness were irradiated perpendicular to the surface with ⁷⁹Au and ⁵⁴Xe ions at specific energies with energy loss values of REL=(10–90) ^*10³ MeVcm²/g at GSI Darmstadt, Germany, and Lawrence Berkeley Lab., Cal., USA. Using the electrolytical etching method by measuring the resistance of the foil during the etching process (etching conditions: 6n NaOH, room temperature and controlled 50° C) the breakthrough time and track etching rates V_t, V_trans and V_m (bulk etching rate) were analysed. Response curves (V_t/V_m)-1 as a function of Restricted Energy Loss (REL), the maximum extension of the ion induced damage perpendicular to the ion path and the dimension of the ion track core depending on the deposited energy can be estimated.