Dentists in Spain reached equal gender representation in 2012 and the number of female dentists has continued to grow (until 57.3% in 2020). This study aims to increase evidence about the gender ...distribution on the high responsibility positions and opinion leaders of the dental profession and academia. Composition of the executive comities of the main dental institutions of Spain (regional professional associations, national dental association, and scientific societies), members of the Faculty of Dentistry of the University of Granada in 2020 and speakers of the main dental congresses of 2019 (due to the lack of congress in 2020) were recorded and analyzed by genders using chi-squared test (P < .05). Mean representation of female dentists in executive committees of professional associations was 35.6%. More than 70% of presidents and vice-presidents of professional colleges and more than 60% of these positions in scientific societies were occupied by male dentists. None of dental congresses of 2019 reached equal gender participation, being 81.3% of lecturers presenting on main auditoriums male dentists. Although dental workforce in Spain is slightly overrepresented by females, leadership positions and figures among Spanish dentists doesn’t seem to reflect the gender distribution of the collective. There is a lack of women occupying high-level positions in dentistry that proves the existence of the so-called “glass ceiling effect” on the profession. Further studies about sociodemographic aspects of dental workforce are needed to develop evidence-based policies for the collective.
CeBr3 crystals meet many of the demands of high performance scintillators, due to their excellent timing properties, good effective Z and high photon yield. It is important to characterize their ...efficiency and to verify whether modern Monte Carlo codes are reliable enough to reproduced the observed values. We report here on the measurement of both total and photopeak efficiency of a 1” diameter×1” height CeBr3 crystal for gamma-ray energies up to 1.4MeV at several distances, using a variety of low energy gamma rays sources. The measured experimental efficiencies are compared with simulations developed in the framework of PENELOPE and GEANT4.
•Measurement of photopeak efficiency of a CeBr3 scintillator coupled to a fast PMT.•Geometry implemented in the PENELOPE and GEANT4 Monte Carlo codes.•Both PENELOPE and GEANT4 reproduce the measured values.•Monte Carlo simulations are sensitive to the details of the geometry.•Simulations useful for this type of crystal with similar or modified geometries
Search for beta-delayed proton emission from 11Be Riisager, K.; Borge, M. J. G.; Briz, J. A. ...
The European physical journal. A, Hadrons and nuclei,
2020/3, Letnik:
56, Številka:
3
Journal Article
Recenzirano
We report on an attempt to reproduce the observation of
β
-
-delayed proton emission from
11
Be through detection of the final state nucleus
10
Be with accelerator mass spectrometry. Twelve samples ...were collected at the ISOLDE facility at CERN at different separator settings, allowing tests of different sources of contamination to be carried out. The observed amounts of
10
Be per collected
11
Be rule out several contamination sources, but do not agree internally. Formation of BeH molecular ions in the ion source may explain our data, in which case an upper limit of the
β
p branching ratio of
2.2
×
10
-
6
can be derived.
CeBr
crystals meet many of the demands of high performance scintillators, due to their excellent timing properties, good effective Z and high photon yield. It is important to characterize their ...efficiency and to verify whether modern Monte Carlo codes are reliable enough to reproduced the observed values. We report here on the measurement of both total and photopeak efficiency of a 1" diameter×1" height CeBr
crystal for gamma-ray energies up to 1.4MeV at several distances, using a variety of low energy gamma rays sources. The measured experimental efficiencies are compared with simulations developed in the framework of PENELOPE and GEANT4.
We present for the first time precise spectroscopic information on the recently discovered decay mode β-delayed 3p-emission. The detection of the 3p events gives an increased sensitivity to the high ...energy part of the Gamow–Teller strength distribution from the decay of 31Ar revealing that as much as 30% of the strength resides in the β3p-decay mode. A simplified description of how the main decay modes evolve as the excitation energy increases in 31Cl is provided.
A novel Phoswich design based on new generation scintillator crystals is presented. The detector composed from a combination of a LaBr3(Ce) with a LaCl3(Ce) crystal in one cylinder coupled to a photo ...multiplier tube has been tested both for incident gamma rays in the range of 0.3–6MeV, as well as for high energy protons in the range 120–180MeV. The Phoswich assembly has not significantly deteriorated the energy resolution, which for 662KeV gamma rays gives a resolution of 4.5%, while for high energy protons (Ep=180MeV) an energy resolution of 1% was obtained. It is shown that the signals from the two crystals can be separated in an event by event based mode. Using direct digitizing of the detector pulse an off-line pulse-shape analysis was performed built either on a total to tail or total to pulse height method in order to fully identify the incoming radiation. Our aim with this R&D is to in the future build a detector which is able to detect with good efficiency and resolution over a wide energy range; 0.1–30MeV gamma rays and 20–400MeV protons. Monte Carlo simulations made in order to design the next prototype are presented.
We have observed β−-delayed proton emission from the neutron-rich nucleus 11Be by analyzing a sample collected at the ISOLDE facility at CERN with accelerator mass spectrometry (AMS). With a ...branching ratio of (8.3±0.9)⋅10−6 the strength of this decay mode, as measured by the BGT-value, is unexpectedly high. The result is discussed within a simple single-particle model and could be interpreted as a quasi-free decay of the 11Be halo neutron into a single-proton state.
•A nanometric mesoporous CaO powder was developed and studied in terms of sintering.•For the first time a nanostructured target material was operated at ISOLDE.•Unlike past CaO targets, stable yields ...over time of n-deficient argon were delivered.•Higher (exotic) Ar yields were obtained at lower temperatures and proton intensities.
At the ISOLDE facility at CERN, thick targets are bombarded with highly energetic pulsed protons to produce radioactive ion beams (RIBs). The isotopes produced in the bulk of the material have to diffuse out of the grain and effuse throughout the porosity of the material to a transfer line which is connected to an ionizer, from which the charged isotopes are extracted and delivered for physics experiments. Calcium oxide (CaO) powder targets have been used to produce mainly neutron deficient argon and carbon RIBs over the past decades. Such targets presented unstable yields, either decaying over time or low from the beginning of operation. These problems were suspected to come from the degradation of the target microstructure (sintering due to high temperature and/or high proton intensity). In this work, a CaO microstructural study in terms of sintering was conducted on a nanostructured CaO powder synthesized from the respective carbonate. Taking the results of this study, several changes were made at ISOLDE in terms of the CaO target production, handling and operation in order to produce and maintain the nanostructured CaO. The new target, the first nanostructured target to be operated at ISOLDE, showed improved yields of (exotic) Ar and more importantly a stable yield over the whole operation time, while operating with lower temperatures. This contradicts the ISOL paradigm of using the highest possible temperature regardless of the target’s microstructure degradation.
We evaluate the performance of two LaBr3(Ce) crystals that were produced with special geometries, aimed at enhancing the scintillation light collection and thus the time resolution. Their design was ...motivated by the construction of high-performance fast-timing arrays like the FAst TIMing array for DESPEC (FATIMA), which demands a high packing factor in addition to good time and energy resolutions.
Energy resolution and efficiency were measured using standard calibration sources. Timing measurements were performed at 60Co and 22Na γ-energies against a fast BaF2 reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the constant fraction discriminator parameters. Monte Carlo simulations using the Geant4 toolkit were performed in order to achieve a better understanding of how the new geometries affect the light transport and thus the performance of the crystals. It is found that the conical-shaped LaBr3(Ce) crystals are optimal for fast-timing applications and for the construction of arrays such as FATIMA.
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