The objective of this study was to characterize the latest version of the electronic D-Shuttle dosimeter (Chiyoda Technol Corp., Tokyo, Japan) for potential use in dosimetry of members of the public. ...The investigations comprise: (a) reproducibility, batch homogeneity, dose linearity, dose rate and angle dependence, and radiation hardness using irradiations at the secondary standard dosimetry laboratory of the Paul Scherrer Institute (PSI); (b) estimation of the environmental dose rate and its variability; and (c) feasibility tests for guests at PSI (short-term researchers). The performed verification measurements showed overall a good reproducibility, maximum 1.4% standard deviation (sd) per dosimeter, and maximum 1.0% sd for 5 dosimeters, in agreement with the manufacturer's specifications. The deviation from linearity was <10% and the deviation with energy was <30% in the range 60 keV, 1.25 MeV, except for 164 keV photons (N-200 radiation quality), where a deviation of almost 50% was observed with respect to the Cs-137 radiation quality. The angle dependence was within specifications (±10%) for Cs-137, but up to +30% for 83 keV photons (N-100 radiation quality). The drop in response for dose rates >0.5–1 mSv/h was well described by an inverse polynomial function, and no influence of a high dose irradiation (16.37 Sv) in subsequent low dose measurements was observed. Environmental background (BG) measurements demonstrated that the dosimeters are stable, showing a mean background indication of (70 ± 30) nSv/h, where the standard deviation is compatible with Poisson statistics assuming a sensitivity of 1 count per 10 nSv. This means that hourly indications above 220 nSv/h (BG + 5 sd) can be clearly distinguished from the background. The monitoring of the guests activities showed that the high sensitivity and hourly information can be useful to investigate out-of-the-ordinary exposures, representing a valuable tool for radiation protection of members of the public.
•Latest version of the electronic D-Shuttle dosimeter was characterized.•Reproducibility, energy response, angle response (Co-60 and N-200) and dose rate response were determined.•The drop in response for dose rates > 0.5–1 mSv/h was well described by an inverse polynomial function.•No influence of a high dose irradiation (16.37 Sv) in subsequent low dose measurements was observed.•High sensitivity and hourly information was shown to be useful to investigate exposures of members of the public.
We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for x>1, which is sensitive to ...short-range contributions to the nuclear wave function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the "superfast" quarks probed at x>1. The falloff at x>1 is noticeably stronger in 2H and 3He, but nearly identical for all heavier nuclei.
Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels gammaover -->p-->pi(+)pi(0)n, gammaover -->p-->pi(0)pi(0)p, and gammaover ...-->p-->pi(+)pi(-)p. The circularly polarized photons, produced from bremsstrahlung of longitudinally polarized electrons, were tagged with the Glasgow magnetic spectrometer. Charged pions and the decay photons of pi(0) mesons were detected in a 4pi electromagnetic calorimeter which combined the Crystal Ball detector with the TAPS detector. The precisely measured asymmetries are very sensitive to details of the production processes and are thus key observables in the modeling of the reaction dynamics.
We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for $x>1$, which is sensitive to ...short range contributions to the nuclear wave-function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the `super-fast' quarks probed at x>1. The falloff at x>1 is noticeably stronger in ^2H and ^3He, but nearly identical for all heavier nuclei.
Photoproduction of π0π0 and π0π± pairs from nuclei has been measured over a wide mass range (2H, 7Li, 12C, 40Ca, and natPb) for photon energies from threshold to 600 MeV. The experiments were ...performed at the MAMI accelerator in Mainz, using the Glasgow photon tagging spectrometer and a 4π electromagnetic calorimeter consisting of the Crystal Ball and TAPS detectors. A shift of the pion–pion invariant-mass spectra for heavy nuclei to small invariant masses has been observed for π0 pairs but also for the mixed-charge pairs. The precise results allow for the first time a model-independent analysis of the influence of pion final-state interactions. The corresponding effects are found to be large and must be carefully considered in the search for possible in-medium modifications of the σ-meson. Results from a transport model calculation reproduce the shape of the invariant-mass distributions for the mixed-charge pairs better than for the neutral pairs, but also for the latter differences between model results and experiment are not large, leaving not much room for σ-in-medium modification.
Coherent photoproduction of η-mesons off 3He, i.e. the reaction γ3He→η3He, has been investigated in the near-threshold region. The experiment was performed at the Glasgow tagged photon facility of ...the Mainz MAMI accelerator with the combined Crystal Ball – TAPS detector. Angular distributions and the total cross section were measured using the η→γγ and η→3π0→6γ decay channels. The observed extremely sharp rise of the cross section at threshold and the behavior of the angular distributions are evidence for a strong ηHe3 final state interaction, pointing to the existence of a resonant state. The search for further evidence of this state in the excitation function of π0-proton back-to-back emission in the γ3He→π0pX reaction revealed a very complicated structure of the background and could not support previous conclusions.
New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from (2)H, (3)He, (4)He, (9)Be and (12)C for 0.3 < x < 0.9, Q(2) approximately 3-6 GeV(2). These data ...represent the first measurement of the EMC effect for (3)He at large x and a significant improvement for (4)He. The data do not support previous A-dependent or density-dependent fits to the EMC effect and suggest that the nuclear dependence of the quark distributions may depend on the local nuclear environment.
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