We have studied the influence of the end of range defects in silicon created by high energy protons and helium ions on subsequent porous silicon formation. The defect generation rate at the end of range is typically ten times higher than that close to the silicon surface. For low fluence irradiation, only the end-of-range region contains enough defects to prevent anodization whereas the low-def...

We provide a review of the current state of dosimetry in prostate photodynamic therapy (PDT). PDT of the human prostate has been performed with a number of different photosensitizers and with a variety of dosimetry schemes. The simplest clinical light dose prescription is to quantify the total light energy emitted per length (J/cm) of cylindrical diffusing fibers (CDF) for patients treated with...

The environmental neutron spectrum has been measured at Zacatecas City in Mexico. Neutron spectrum was unfolded from count rates obtained with a multisphere neutron spectrometer with a LiI(Eu) scintillator. With the spectrum information the ambient dose equivalent and the isotropic effective dose were calculated. A model based upon the geomagnetic latitude and the altitude above sea level, that...

In the present work, the general purpose radiation transport MCNPX code (version 2.5.0) was used to evaluate the neutron fluence response matrix of the passive Bonner sphere spectrometer recently developed in our laboratory. The calculations were performed for an extended neutron incidence energy range (from 10−9 MeV to 1 GeV). Afterward, a sensitivity analysis of the main parameters affecting ...

Low temperature ion bombardment of initially crystalline, defect-free silicon with 700 eV ion beam energy creates a highly-damaged stressed layer a few nanometers thick on the surface. An apparent steady state in structure is achieved at a fluence of 2 · 10–3 · 10 ions/cm. In this work, the stresses are computed using the interatomic force definition of stress. The stress evolution is studied a...

Time resolved laser induced incandescence (LII) technique is used to measure size distribution of soot nanoparticles of candle's flame. Pulsed Nd:YAG laser is used to heat nanoparticles to incandescence temperature and the resulting signal is measured. Mass and energy balance equations are numerically solved to calculate temperature of soot particles in low fluence regime. Assuming Plank black ...

Fullerene C60 films deposited by sublimation were irradiated with Kr-F laser in a wide fluence interval from 15 to 40 mJ/cm2. In situ photoacoustic analysis was applied to study the phase transformation during the irradiation. The results obtained were discussed in conjunction with atomic force microscopy (AFM) and Raman spectroscopy data. It was found that for a irradiation fluence interval fr...

The organic phosphor p-terphenyl is used as a wavelength-converter coating in some soft-x-ray detectors. We have measured the absolute photoluminescent efficiency of p-terphenyl as a function of incident photon energy from 36 to 191 eV. We have also measured changes in the efficiency caused by soft-x-ray fluence (total photons absorbed per unit area) at several photon energies in this range. We...

Laser ablation involves heating, evaporation of target material and ionization of vapor to form plasma plume surrounding the ablation spot. A self consistent model, that combines target heating, evaporation, ionization, shielding and expansion of plume, is employed to obtain ablation parameters. The results showed good agreement with experiments. For a given laser energy fluence and target mate...