Function Of Residual Range Research Articles

V-function to investigate tracks of the alpha particle irradiated CR-39 detector

In this work, the etch-rate ratio V of CR-39 detector irradiated by alpha particles was investigated at different alpha particle energies. The study involved a new empirical equation for V as a function of residual range R'. The introduced equation encompassed five free parameters ɑ1 = 0.098 μm−1, ɑ2 = 1.86, ɑ3 = 37.78 μm, ɑ4 = 36.98 μm and ɑ5 = 0.98 which showed good agreement with the experimental data. Moreover, the equation agreed well with other V functions illustrated elsewhere.

Calibration of the charge and energy loss per unit length of the MicroBooNE liquid argon time projection chamber using muons and protons

We describe a method used to calibrate the position- and time-dependent response of the MicroBooNE liquid argon time projection chamber anode wires to ionization particle energy loss. The method makes use of crossing cosmic-ray muons to partially correct anode wire signals for multiple effects as a function of time and position, including cross-connected TPC wires, space charge effects, electron attachment to impurities, diffusion, and recombination. The overall energy scale is then determined using fully-contained beam-induced muons originating and stopping in the active region of the detector. Using this method, we obtain an absolute energy scale uncertainty of 2% in data. We use stopping protons to further refine the relation between the measured charge and the energy loss for highly-ionizing particles. This data-driven detector calibration improves both the measurement of total deposited energy and particle identification based on energy loss per unit length as a function of residual range. As an example, the proton selection efficiency is increased by 2% after detector calibration.

Variation of the track length along the particle trajectory through CR-39 stack sheets

An alpha track was selected through a number of successive CR-39 sheets in a high energy nuclear reaction experiment. The experiment was aimed at identifying particles emitted at an angle of 25° to the beam direction when bombarding a copper disk with relativistic fluorine ions. Most of these particles were identified as protons and alpha particles. The experiment showed that the inlet energy of an alpha particle to be detectable in CR-39 plastic is 53.4 MeV per nucleon. The CR-39 range of such particles is ∼2 cm long. The corresponding range for a proton is ∼1 mm long. The track diameter at positions on the track length can display the damage as a function of the depth in the CR-39 material. In addition, the track length is measured along the particle trajectories in CR-39 sheets for a single track as a function of residual range in the CR-39 material. The restricted energy loss (REL) for alpha tracks in CR-39 is calculated using the Henke–Benton computer program. Comparison between the REL and the damage was available along this track, especially owing to the ability of CR-39 to prevail etched tracks.

An approach to nuclear charge identification with CR-39 polymeric nuclear track detector

The etch-rate ratio V of CR-39 (DOP) nuclear track detector as a function of residual range R for 1 ≤ Z ≤ 26 nuclei have been determined. On the base of the sensitivity function V( R), an attempt has been made to study the possibility of particle identification technique in CR-39 by plotting the calculated etched-track cone length versus the starting range for various ions in the range 0.1 < E A ≤ 140 MeV/u . A correlation has been established between the nuclear charge and the etched-track parameters. The present calculation shows the possibility of identifying the charge of a nuclear particle with appreciable charge resolution.

Very heavy ion track etching in olivine

Track etch rate has been measured as a function of residual range R for 12–16 MeV/amu Kr, Pb and U ions in olivine, and has been found not to vary with R for Pb and U ions. For this reason, 16 MeV/amu U ions have been used to specifically study the influence of the etching process on track etch rate in this mineral. The track etch rate is found to decrease with time, i.e. with etched track length, even for constant radiation damage. Small changes in composition of the WN etchant can considerably modify the olivine bulk etch rate and, to a much lesser extent, the tract etch rate. Evidence is presented for the existence of an etch induction time, with characteristics strikingly similar to those known for plastic track detectors, and of the etch blocking features, some of which have been identified with tubular inclusions. An attempt is made to explain and link together these experimental results. The track etch rate is expressed in terms of a competition between two components, one depending on radiation damage, the other on etching chemistry. Implications for the interpretation of track etch rate measurements and for proper revelation of tracks, in particular very long tracks, are pointed out.

Heavy ion track etch rate measurements and track structure in a mineral

Track etch rate has been measured as a function of residual range, for various heavy ions (Kr, Xe, Au, Pb, U), in olivine. We discuss the experimental conditions in which this kind of measurement can be free of effects due to the etching process itself, and really reflect the defect structure of the latent tracks. The results are compared with model predictions.

Particle identification from track-etch rates in minerals

A method of charge identification from etched tracks in minerals is presented which utilizes etch-rate measurements as a function of particle range, as is commonly done in plastic track detectors. Sucha method could have considerable application in cosmic ray studies in meteoritic minerals, and also possibly in nuclear reaction studies. Calibration of the track-etch rate to primary ionization is effected externally by accelerator irradiations, the information on track-etch velocity as a function of residual range [ V t( R)] being obtained in a number of ways. Fitting of a response curve for various values of the constant K allows an optimum value of this parameter to be found; and by using this value, fitted V t( R) profiles can be built up, which lead to charge identification. It is found that Ca and Ti track-etch rates are not compatible with data from heavier nuclei. This fact may throw some light on the nature of the track-formation process.

Studies of fresh and fossil tracks in meteoritic hypersthene

From measurements of the total recordable lengths of fossil tracks and freshly-produced Fe ion tracks in meteoritic hypersthene, the abundance of Fe relative to all VH ions (20 ≦ Z ≦ 28) in the time-averaged cosmic-ray flux is found to be ≈ 0.35. After allowance is made for the effects of fragmentation of nuclei at a depth of ≈ 11 cm within the meteorite, this value is found to be in broad agreement with presentday measurements. These crystals have been irradiated with a number of heavy ions with a view to calibrating them for the identification of VVH cosmic rays by measurement of track-etch velocity, V T , as a function of residual range. A good fit to the calibration data is obtained by using a value for the constant K in the primary-ionization equation of 10.5 (±0.5). The relationship between V T and primary ionization J appears to be approximately linear.

Identification of heavy ions in AgCl monocrystals by means of multiple coulomb scattering

The scattering constant of AgCl monocrystals was estimated by comparing the multiple Coulomb scattering of stopping 16O ions as a function of residual range in an AgCl monocrystal and in Ilford G5 nuclear emulsion. The ratio of scattering constants for the two media was found to be 1.255±0.038, as compared to the theoretical prediction of 1.273.Absence of sizeable distortion in the monocrystal was checked by measurements on fast 16O ion tracks.The reading noise level on the AgCl tracks was found to be at most equal to that in nuclear emulsion. From the observed dispersions it is estimated that a track length of 8 mm in the monocrystal should be sufficient to estimate the ion charge within one unit.

Characteristics of tracks of ions of 14⩽Z⩽36 in common rock silicates

This paper concerns the identification of heavy ion tracks in minerals by measurements of track-etch rates and total etchable track lengths. With beams of Si, Cl, Ti, Fe, Zn and Kr at energies up to 10.35 MeV/nucleon we have irradiated nine minerals commonly used to study fossil cosmic ray tracks in meteorites and lunar samples. From our measurements of etched track length as a function of residual range, we have determined response curves for various minerals as a function of ionization rate, using the expression previously derived by Price, Fleischer and Moak. These curves increase smoothly with ionization rate instead of rising abruptly at some critical value as was previously thought. We have shown that the track etch rate concept accounts qualitatively for total etchable track length distributions, but that the positions of the peaks of different elements in these histograms occur at shorter lengths for fossil tracks than for fresh tracks. Our annealing data indicate that, at maximum lunar surface temperatures, tracks in olivine, orthopyroxenes and feldspars may be significantly shortened whereas tracks in clinopyroxenes will not be affected. We cite additional evidence that gradual rearrangement of radiation damage at ambient temperature makes the properties of fresh tracks and of ancient tracks different. It is thus not surprising that the histograms of fresh and fossil tracks do not match perfectly.

Penetration of Electron Beams into Water below the Critical Energy

The moments technique has been applied to the calculation of the spatial distribution of the energy dissipation in water by electron beams of energies 10 to 25 Mev. A continuous energy loss is assumed and the energy-range relationships are obtained taking into account the ionization and radiation losses. These relationships are introduced in the proper Boltzmann transport equation to approximate the scattering term by a simple function of residual range. The stopping power is approximated by a sum of powers of residual range. This leads to expressing the spatial moments of the energy dissipation as a combination of triple moments of the electron distribution function. These triple moments are the angular, spatial, and residual range moments, which are connected by a recursion system. The first three moments are calculated together with the boundary condition and the asymptotic trend. With this information, the distribution is constructed by using a simple analytical function. The agreement with experimental results is satisfactory. (auth)