Radiation effects induced in pin photodiodes by 40- and 85-MeV protons

PIN photodiodes were bombarded with 40- and 85-MeV protons to a fluence of 1.5 x 10 to the 11th power p/sq cm, and the resulting change in spectral response in the near infrared was determined. The photocurrent, dark current and pulse amplitude were measured as a function of proton fluence. Changes in these three measured properties are discussed in terms of changes in the diode's spectral response, minority carrier diffusion length and depletion width. A simple model of induced radiation effects is presented which is in good agreement with the experimental results. The model assumes that incident protons produce charged defects within the depletion region simulating donor type impurities

Data from: Phylogenetic signal in mitochondrial and nuclear markers in sea anemones (Cnidaria, Actiniaria)

The mitochondrial genome of basal animals is generally more slowly evolving than that of bilaterians. This difference in rate complicates the study of relationships among members of these lineages and the discovery of cryptic species or the testing of morphological species concepts within them. We explore the properties of mitochondrial and nuclear ribosomal genes in the cnidarian order Actiniaria, using both an ordinal-scale and familyfamilial-scale sample of taxa. Although the markers do not show significant incongruence, they differ in their phylogenetic informativeness and the kinds of relationships they resolve. Among the markers studied here, the fragments of 12S rDNA and 18S rDNA most effectively recover well-supported nodes; those of 16S rDNA and 28S rDNA are less effective. The general patterns we observed are similar to those in other hexacorallians, although Actiniaria alone show saturation of transitions for orderordinal-scale analyses

Examination of general cavity theory for magnesium and titanium doped lithium fluoride (TLD-100) of varying thicknesses in bone and lung

Purpose To evaluate the accuracy of Burlin cavity theory for TLDs in bone and lung, the two most relevant heterogeneities in radiological physics. Methods Theoretical calculations and Monte Carlo (MC) simulations of dose to TLD to dose to medium correction factor, (f)med TLD, were performed and compared in bone and lung. MC simulations included virtual irradiation of TLDs with varying thicknesses (0.015, 0.038, and 0.089 cm) in bone, lung, and water phantoms. Theoretical calculation of Burlin cavity theory requires calculation of fractional dose contribution from photon interactions (d) from mass effective attenuation coefficient (ß) and average path length of electrons penetrating in the cavity from the wall (g). Different theoretical formulations of g and ß were used to calculate 18 different values for d and (f)med TLD. Further, the impact of mean energy approximation used in theoretical calculations was evaluated using full spectrum MC simulations. Results While the values of d differed as much as by a factor of 2, (f)med TLD agreed well (SD = 0.1%) in water, bone and lung. The TLD thickness ranging 0.015–0.089 cm was not a significant factor (SD = 0.2%). Dose correction factors calculated using mean energy approximation agreed within the 2% with full spectrum MC simulations. Uncertainty associated with theoretical calculation of (f)med TLD was 7.2% compare to 0.5% with MC simulation. Conclusion The (f)med TLD calculated with Burlin theory agreed well with MC results for 6 MV photon beam. Nevertheless, the difficulty and the ambiguity in the determination of ß and g in a given medium and the energy spectrum under investigation limited the theoretical calculations and resulted in large uncertainty. This study suggests the use of MC for easy and accurate estimation of(f)med TLD, which is required in radiological applications to convert TLD measured dose to dose in medium. © 2016 Elsevier Lt