We present the yield and spectra of stable secondary particles (γ, e±, νe, ν̄e, νμ, and v̄μ of p-p interaction in parameterized formulae to facilitate calculations involving them in astronomical ...environments. The formulae are derived from the up-to-date/p-p interaction model by Kamae et al. (2005), which incorporates the logarithmically rising inelastic cross section, the diffraction dissociation process, and the Feynman scaling violation. To improve fidelity to experimental data in lower energies, two baryon resonance contributions have been added: one representing Δ(1232) and the other representing multiple resonances around 1600 MeV/c-2. The parameterized formulae predict that all secondary particle spectra be harder by about 0.05 in power-law indices than that of the incident proton and their inclusive cross sections be larger than those predicted by p-p interaction models based on the Feynman scaling.
There is a need for improved physics models to correctly predict single event effects (SEEs) caused by nuclear reaction products from heavy ion radiation. Previous validations for nuclear ...fragmentation simulations are shown to be insufficient to support SEE analysis applications. A comparison of different physics models with experimental nuclear physics data coupled with energy deposition predictions is presented.
We performed an experimental study of charge identification of heavy ions from helium to carbon having energy of about
290
MeV
/
u
using an emulsion chamber. Emulsion was desensitized by means of ...forced fading (refreshing) to expand a dynamic range of response to highly charged particles. For the track reconstruction and charge identification, the fully automated high speed emulsion read-out system, which was originally developed for identifying minimum ionizing particles, was used without any modification. Clear track by track charge identification up to
Z
=
6
was demonstrated. The refreshing technique has proved to be a powerful technique to expand response of emulsion film to highly ionizing particles.
Recent developments in Geant4 Allison, J.; Amako, K.; Apostolakis, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2016, Letnik:
835, Številka:
C
Journal Article
Recenzirano
Odprti dostop
Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including ...high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made to the toolkit in order to accommodate the needs of these user communities, and to efficiently exploit the growth of computing power made available by advances in technology. The adaptation of Geant4 to multithreading, advances in physics, detector modeling and visualization, extensions to the toolkit, including biasing and reverse Monte Carlo, and tools for physics and release validation are discussed here.
•Multithreading resulted in a smaller memory footprint and nearly linear speed-up.•Scoring options, faster geometry primitives, more versatile visualization were added.•Improved electromagnetic and hadronic models and cross sections were developed.•Reverse Monte Carlo and general biasing methods were added.•Physics validation efforts were expanded and new validation tools were added.
A new universal coding/decoding scheme for random access with collision detection is given in case of two senders. The result is used to give achievable joint source-channel coding error exponents ...for multiple access channel and independent sources. In a modified model admitting zero rate communication between the senders, an improved exponent is derived, of form similar to Csiszár's joint source-channel exponent for the one-sender case.
The molecular interaction between smooth muscle (SM) myosin and actin in the corpus cavernosum (CC) determines the erectile state of the penis. A key mechanism regulating this interaction and ...subsequent development and maintenance of force is alternative splicing of SM myosin heavy chain (MHC) and 17 kDa essential SM myosin light chain (MLC) pre-mRNAs. Our aim was to examine the relative SM myosin isoform composition in human CC. Tissue samples were obtained from 18 patients with erectile dysfunction (ED), Peyronie's disease, or both. One specimen was obtained during a transgender operation. Patients then were stratified according to presence of diabetes mellitus, hypertension, ED, or Peyronie's disease, as well as failure of phosphodiesterase-5 (PDE5) inhibitors and history of previous pelvic or penile surgeries, radiation, or both. Our results revealed that all human CC samples expressed only the SM-A isoform. There was a predominance of SM2 isoform mRNA relative to SM1 across all samples, with a mean of 63.8%, which correlated with protein analysis by gel electrophoresis. A statistically significant difference was found between patients who had undergone previous pelvic surgery, radiation, or both and those who did not. The ratio of LC(17b) to LC(17a) was approximately 1:1 for all patients, with a mean of 48.9% LC(17b). Statistical difference was seen in the relative ratio of LC(17b) to LC(17a) among the group who failed conservative therapy with PDE5 inhibitors compared with all others. In conclusion, we determined the SM myosin isoform composition of human CC and present for the first time differences in relative myosin isoform expression among patients with several risk factors contributing to their cause of ED. Our data reflect the fact that alternative splicing events in the MHC and 17 kDa MLC pre-mRNA may be a possible molecular mechanism involved in the altered contractility of the CCSM in patients with ED.
We tested the ability of two separate nuclear reaction models, the binary cascade and JQMD (Jaeri version of Quantum Molecular Dynamics), to predict the dose distribution in carbon-ion radiotherapy. ...This was done by use of a realistic simulation of the experimental irradiation of a water target. Comparison with measurement shows that the binary cascade model does a good job reproducing the spread-out Bragg peak in depth-dose distributions in water irradiated with a 290 MeV/u (per nucleon) beam. However, it significantly overestimates the peak dose for a 400 MeV/u beam. JQMD underestimates the overall dose because of a tendency to break a nucleus into lower-
Z
fragments than does the binary cascade model. As far as shape of the dose distribution is concerned, JQMD shows fairly good agreement with measurement for both beam energies of 290 and 400 MeV/u, which favors JQMD over the binary cascade model for the calculation of the relative dose distribution in treatment planning.
To determine for how long a landslide affects sediment discharge, the sediment yields of 15 check-dam basins were compared with the time series of landslide distributions in a mountain basin in the ...Tanzawa region, central Japan. The distribution of sediment yield was quantitatively estimated from deposition in the sediment pools of check dams. The relationship between the landslide history and sediment discharge in the Nakagawa River basin was examined for an approximately 80-year period. Two major landslide events occurred during this period: the 1923 Kanto Earthquake and the 1972 disaster caused by heavy rainfall. The resulting trend in sediment discharge of the whole basin, estimated using reservoir sedimentation in the Miho Dam at its base, was nearly constant, with high sediment discharge (2897 m
3 km
−
2
yr
−
1
) in the intervening quarter-century, despite the recovery of vegetation on landslide areas in this period. Comparisons of the landslide distributions resulting from the two disasters, the sediment yields of check-dam basins, and the sediment discharge of the whole basin indicate that recent sediment discharge contains landslide debris that was originated by the Kanto Earthquake that occurred over 80 years ago. Thus, to understand high sediment discharge, it is essential to investigate not only the current basin condition and recent events, but also the landslide history of the basin for at least the previous 100 years.
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