S. Manzoor

Hardware performance of a scanning system for high speed analysis of nuclear emulsions

The use of nuclear emulsions in very large physics experiments is now possible thanks to the recent improvements in the industrial production of emulsions and to the development of fast automated microscopes. In this paper the hardware performances of the European Scanning System (ESS) are described. The ESS is a very fast automatic system developed for the mass scanning of the emulsions of the OPERA experiment, which requires microscopes with scanning speeds of � 20 cm 2 =h in an emulsion volume of 44mm thickness.

Fragmentation studies of 158 A GeV Pb ions using CR39 nuclear track detectors

Abstract Six stacks of CR39 [(C12H18O7)n, a Registered Trade Mark of PPG Industries, Inc.] nuclear track detectors with different targets were exposed to a lead ion beam of 158 A GeV at the CERN-SPS, at normal incidence, in order to study the fragmentation properties of ultra-relativistic lead nuclei. Measurements of the total, break-up and pick-up charge-changing cross sections of 158 A GeV Pb ions have been made for the first time.

Evaluation of excessive lifetime cancer risk due to natural radioactivity in the rivers sediments of Northern Pakistan

Abstract Naturally occurring radionuclides 226Ra, 232Th and 40K present in the rivers sediments of Northern Pakistan were measured using HPGe γ-ray spectrometer to evaluate the radiation health hazard indices and excess lifetime cancer risk (ELCR). Average concentrations of 226Ra, 232Th and 40K in the sediments were found to be 50.66±1.29, 70.15±1.45 and 531.70±5.45Bqkg−1 respectively. Radium equivalent activity (190.89Bqkg−1), outdoor external dose (87.47nGyh−1), indoor external dose (165.39nGyh−1), and total average annual effective dose (0.92mSv) were calculated. The hazardindices are higher than the worlds average values. Total excess lifetime cancer risk (ELCR) was found to be 3.21×10−3 which is relatively higher. Numerous cancer deaths are annually reported from the Northern areas of Pakistan, which may be related to high radioactivity in the area.

Search for a Lorentz invariance violation contribution in atmospheric neutrino oscillations using MACRO data

The energy spectrum of neutrino-induced upward-going muons in MACRO has been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of v(u) -> v(tau) transitions. The data disfavor these exotic possibilities even at a subdominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter vertical bar Delta v vertical bar < 6 x 10(-24) at sin2 theta(v) = 0 and vertical bar Delta(v)vertical bar < 2.5-5 x 10(-26) at sin 2 theta(v) = +/- 1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the equivalence principle. (c) 2005 Elsevier B.V. All rights reserved.

Thermal annealing of fission fragment radiation damage in CR-39

Abstract The annealing behavior of fission fragment tracks in CR-39 has been studied at different temperatures for various time intervals. Experimental data, obtained in isothermal and isochronal annealing experiments carried out on CR-39 irradiated with fission fragments of 252 Cf, has been analyzed on the basis of different annealing models. It has been attempted to find out the validity of these models, developed on the basis of annealing data in minerals and other detectors, to the annealing data of fission fragment tracks in CR-39.

Mass and energy dependence of pion-induced fission

Data for fission induced by pi meson beams from 80 to 500 MeV are presented for nuclei from Fe through Pu as measured by solid state track detectors. The general trends for binary fission withπ+ are reproduced fairly well by a calculation in the ‘high excitation’ limit with standard level density and fission barrier parameters, butπ− data are underpredicted. A universal dependence of the binary fission probabilities with the fissility (Z±1)2/A is found to be valid for both pion beam charges for all beam energies below the delta resonance. Probabilities for observing three fragments withπ+ are not reproduced by a ternary fission application of the model found to work for binary fission.

Nuclear Track Detectors for Environmental Studies and Radiation Monitoring

Several improvements were made for Nuclear Track Detectors (NTDs) used for environmental studies and for particle searches. A new method was used to determine the bulk etch rate of CR39 and Makrofol NTDs. It is based on the simultaneous measurement of the diameter and of the height of etch-pit cones caused by relativistic heavy ions (158 A GeV Pb 82+ and In 49+ ions) and their fragments. The use of alcohol in the etching solution improves the surface quality of NTDs and it raises their thresholds. The detectors were used for the determination of nuclear fragmentation cross sections of Iron and Silicon ions of 1.0 and 0.41 GeV/nucleon. These measurements are important for the determination of doses in hadrontherapy and for doses received by astronauts. The detectors were also used in the search of massive particles in the cosmic radiation, for the determination of the mass spectrum of cosmic rays and for the evaluation of Po 210 α -decay and of natural radon concentrations.

Activation energy for the annealing of nuclear tracks in SSNTDs

Abstract Annealing characteristics of fission fragment tracks in CR-39 have been studied to find out the activation energy. Published annealing data sets of different ions in CR-39 and various other detectors have also been re-analyzed to study the dependence of activation energy of annealing on different factors involved in the process. This analysis shows that the activation energy of annealing depends mainly on the characteristics of the detector material but it may have weak dependence on the parameters of track forming ion and annealing conditions.

Experimental and simulation study of neutron dosimetry at various neutron energies

Abstract A Monte Carlo Neutron Photon (MCNP) transport code has been employed to simulate CR-39 plastic track detector as neutron dosimeter at various neutron energies. In each simulation a monoenergetic neutron source of a particular energy was embedded in the center of a sphere made of CR-39. Surrounding the source there were concentric shells of 2 μm CR-39 track detectors. The code, MCNP, was run on personal computer for 7.5×106 histories. The number of proton recoils in each shell of 2 μm of CR-39 were determined. The simulation results show that apart from proton recoils (for En > 1.0 MeV), about 50% recoils are due to heavy charged particles i.e. Oxygen and Carbon in CR-39. This indicates that etched tracks are not only due to recoil of protons but also due to recoil of heavy charged particles. The upper limits of the track registration efficiencies have been determined as a function of neutron energies. These simulation results have been experimentally verified using CR-39 track detectors at various known energies of neutrons. The proton and heavy charged particle recoil tracks in CR-39 were made visible by etching in NaOH solution, at 70±1°C for 1.75 hours.

On the use of SSNTD in relativistic heavy ion physics and the study of open questions

Abstract Taking an historic perspective on the development of relativistic physics in general and relativistic heavy ion physics in particular, it can be shown that many observations were first made with nuclear emulsions and other SSNTD detectors, later confirmed with conventional counter techniques and/or radiochemical techniques. It is quite possible that SSNTD can make similar contributions when studying the open and controversal problems of today. In this article we consider the anomalon phenomenon as to be one such problem.