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1.
The track etch rates of
10
20
Ne-ion in cellulose nitrate (LR-115) have been measured for different temperatures and the activation energy is determined.
The experimental results show that both the track etch rate and the normalized track etch rate depend on the energy loss as
well as on etching temperature. The maximum etched track length of
10
20
Ne-ion agrees with the theoretically computed range. The experimental results show that there is no sharp threshold, at least
in CN(LR-115). 相似文献
2.
Measurements of the dependence of track etch rate on the energy-loss of different ions have been presented. In this method,
18
40
Ar,
10
22
Ne,
8
16
O and
6
12
C-ions of different energies are used as energetic heavy ions for track formation in the detectors. The bulk etch rate and
track etch rate are measured for different temperatures and hence the activation energies are determined. The variation of V = V
t
/ V
b
along the trajectory of the track has been shown for different temperatures. The maximum etched track length is compared
with the theoretical range as well as with the range reported earlier. The experimental results indicate the absence of a
well-defined threshold in the plastics studied. 相似文献
3.
The etch pit diameters of soda glass detector samples exposed to
54
132
Xe-ions of different energies are measured for different etching times after etching the detector in a ‘new etchant’ free
of the adverse effect of the etch product layer. The dependence of track diameter on the energy and on the energy loss, d E/d x of
54
132
Xe-ion in soda glass has been presented. The energy resolution of soda glass and the critical angle for etching of fission
fragment tracks in glass detectors have also been determined. The maximum etched track length of
54
132
Xe-ion in soda glass has been compared with the theoretical range. The effects of different annealing conditions on bulk etch
rate of glass detector and on diameters of
54
132
Xe-ion tracks have been presented. Experimental results show that there is a decrease in track etch rate, etching efficiency
and etchable range of
54
132
Xe-ions with annealing. The annealing of oblique tracks shows that the vertical tracks are more stable than the oblique tracks. 相似文献
4.
Samples of Lexan and Makrofol-E polycarbonate plastic track detectors were exposed to 1·1 MeV/N
54
132
Xe-ions to investigate the thermal track fading properties of these plastics. The experimental results show that there is
no effect of annealing on the bulk etch rate while the track etch rate decreases with annealing. The track diameter decreases
with increase in annealing time and temperature. It is also observed that the track density is reduced as a result of annealing.
The experiments reveal that the track lengths are, in general, decreased by the application of heat and that the oblique tracks
are less stable than the vertical tracks. The decrease in diameter of
54
132
Xe-ion tracks in Makrofol-E due to heat treatment is faster than that of
54
132
Xe-ion tracks in Lexan. 相似文献
5.
Sample of cellulose nitrate (Russian) is exposed to
18
40
Ar ions. The bulk etch rate has been studied at different etching temperatures and the activation energy for bulk etch rate
has been calculated. The etched track lengths are measured for different etching times. The energy loss rate and range of
18
40
Ar ions in CN(R) is also calculated. The critical threshold value for etchable track in CN(R) is determined by comparing the
theoretical and experimental values of track length. The response curve of CN(R) is also presented. 相似文献
6.
Triafol-TN plastic detector foils have been irradiated with 238U ions of energy 16.34 MeV/u and the tracks produced have been observed using the chemical etching technique. The bulk etch rate and track etch rate are determined under successive chemical etching. In our case, the validity of Arrhenius’s law is confirmed by the fact that the same value of E a obtained for these different concentrations, within experimental errors. The results show a linear correlation between the measured track etch rate along the track and the corresponding total energy loss rate and a threshold value of ~ 5.0 MeV/(mg/cm 2) for track registration was obtained. The maximum etched track length of 238U-ion in triafol-TN has been compared with the theoretically computed range. 相似文献
7.
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. 相似文献
8.
Abstract Thermal annealing of latent tracks caused by the passage of heavy ions, viz. Pb 208 (13.8 MeV/n) and Ni 58 (15.37 MeV/n), in muscovite mica is investigated. The activation energy for track annealing, determined using different annealing models, is compared. The effect of thermal annealing on size and energy resolution of heavy ions in mica, based on the track etch rate and track length reduction, is discussed. 相似文献
9.
Computation of the neutron response of CR-39 detectors needs to simulate the track formation by neutron induced charged particles taking into account the bulk etch rate and the track etch rate varying along the particle trajectories. The latter one was determined experimentally by track length measurement. The results allowed to derive the relationship between the track etch rate and the restricted energy loss of the charged particles. On this basis, the geometrical track parameters and track etch rates as well as the critical angle of particle incidence could be determined for protons and alpha particles in the energy range from 0.2 to 8.8 MeV. The energy dependence of the critical angle enabled to determine the detection efficiency for a charged particle of given energy and direction. 相似文献
10.
Latent damage tracks of energetic 40Ar ions (18·56 MeV/ u) have been recorded in Lexan polycarbonate detector. Bulk and track-etch parameters are evaluated under successive chemical
etching. Our results show a linear correlation between the measured track-etch rate along the track and the corresponding
total energy-loss rate and predict a threshold value of 5·0 MeV mg −1 cm 2 for track registration. Maximum etchable track lengths of 40Ar ions as a function of energies have also been measured and compared with three different sets of theoretical ranges. 相似文献
11.
Solid-state nuclear track detectors (SSNTDs) have found wide use in various domains of science and technology, e.g. in environmental experiments. Measurement of α activity on sources in an environment, such as air, is not easy because of the short penetration range of the α particles. Furthermore, the measurement of α activity by most gas ionization detectors suffers from the high background induced by the accompanying gamma radiation. SSNTDs have been used successfully as detecting devices as passive system to detect the α contamination of different surfaces. This work presents the response of CR-39 (for two types) to α 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. 相似文献
12.
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.
相似文献
13.
Differential cross-sections for the reactions d (γ,π 0) d and d (γ,π 0) pn have been measured at MAMI with the TAPS detector setup in the energy range 140 MeV < E
γ < 306 MeV. By use of the Glasgow tagging spectrometer an 0.8 MeV energy resolution for photons incident on the target was
achieved. The π 0 missing energy resolution was sufficient for a reliable separation of coherent and incoherent channels. The data for the
break-up channel exhibit very strong final state interaction effects, whereas the observed angular dependence of the inclusive
process d (γ,π 0) X is in quantitative agreement with predictions for a quasi-free process. The observed absolute d (γ,π 0) X cross-sections, on the other hand, are significantly smaller than predicted by the quasi-free process for E
γ >∼ 250 MeV. Associating this failure with the π 0 photoproduction on the neutron would suggest that its cross-section is up to 25% below the presently believed value.
Received: 13 February 2001 / Accepted: 13 April 2001 相似文献
14.
The three-body Faddeev equations for neutron-deuteron scattering are solved in the energy region from 2.5 MeV to 50 MeV of the incident neutron energy with small energy steps. Higher-rank separable potentials are used in the 1
s
0 wave and in the 3
s
1— 3
d
1 waves, while rank-1 separable potentials are used in 1
p
1, 3
p
0,1,2
1
d
2
3
d
2,3 waves. The calculation is compared with experiments for the total cross section, the total break-up cross section, the differential cross section and the analyzing power of neutron-deuteron scattering. The improvements in the agreement as compared to previous calculations are impressive in many cases. Especially, the calculated total cross section agrees with the experiment below 30 MeV within the error bars, which are as small as 1%. A discussion on the numerical accuracy is given. General aspects of the calculated cross section are discussed. It is pointed out that the s-wave asymptotic normalization of the deuteron wave function ( A
s
) is important. 相似文献
15.
The bulk etch rate for two types of CR-39 detector was measured as a function of temperature and the activation energies of bulk etching was determined. Experimental values of track etch rate were derived directly from the function of the succesive measured track length vrs. etching time for 209Bi, 129Xe and 20Ne ions. The maximum etchable length of 13 MeV/u 209Bi and 13.04 MeV/u 129Xe ions have been measured at and below these energies. A comparison of the measured and calculated track length data is presented. 相似文献
16.
Bubble detectors which are commonly used as neutron detectors have been demonstrated through this study to be good detectors for registration of high energy heavy ion tracks. Large size bubble detectors made in China Institute of Atomic Energy were irradiated to heavy ions Ar and C up to 650 MeV/u and 400 MeV/u, respectively. Very clear features of stringy tracks of high energy heavy ions and their fragmentations are manifested and distinguishable. A single track created by a specific high energy heavy ion is composed of a line of bubbles, which is visible by naked eyes and retained for months wihhout reduction in size. The creation of heavy ion tracks in bubble detectors is governed by a threshold whose essence is approximately a critical value of energy loss rate (dE/dX) c similar to that of etch track detectors. Ranges of heavy ions in bubble detectors are apparent and predictable by existing formulas. Identification of high energy heavy ions and the applications to heavy ion physics, cosmic rays, exotic particles and cancer therapy monitoring are obviously promising. The experimental and theoretical aspects of high energy heavy ion tracks in bubble detectors as well as the expectable applications are presented and discussed. 相似文献
17.
The reaction γ d↦π 0
X has been measured with TAPS at MAMI in the energy range E
γ = 140-300 MeV. Using the Glasgow tagging spectrometer a photon energy resolution of 0.8 MeV was achieved. The energy excitation
functions of integral and differential total cross-sections show no structures of statistical significance > 2σ. Upper limits
for the production of narrow isoscalar or isovector dibaryons with masses m? 2100 MeV/c 2 were deduced. They are in the range 2-5 μb averaged over the 0.8 MeV energy resolution.
Received: 25 October 2000 / Accepted: 24 November 2000 相似文献
18.
Etched track opening geometries in Biotite, Phlogopite and soda-lime glass irradiated with swift heavy ions [ 197Au(11.64 MeV/n), 136Xe(11.56 MeV/n), 58Ni(11.56 MeV/n)] at different angle of incidence have been studied using appropriate chemical etching technique. Different
geometries (Hexagonal, irregular polygon, triangular in case of Biotite and Phlogopite, and circular & elliptical in case
of soda lime glass detector) of heavy ion tracks are reported in the present investigations using optical microscope. The
different shapes of these heavy ions track geometries are found to be related with various target-projectile parameters ( viz: type of projectiles, energy, stopping power, angle of incidence of the projectile, density of defects and its reactivity
with etchant, etching conditions and chemical structure of the detectors). The dependence of different shapes of heavy ion
tracks in isotropic and anisotropic medium on the variation of radiation damage densities along the ion trajectories have
also been discussed in the present paper.
相似文献
19.
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. 相似文献
20.
The tensor analyzing power fzz has been measured for the 3He(
, p) 4He reaction at 0 = 0° over an incident deuteron energy range Ed = 6.6–15.8 MeV in steps of 0.5 MeV. The present results agree with and extend the previous measurements of Grüebler et al. The present results indicate that this reaction is a very good tensor analyzer for polarized deuteron beams with energies up to 15.8 MeV. 相似文献
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