48 research outputs found
A new ultra low-level HPGe activity counting setup in the Felsenkeller shallow-underground laboratory
A new ultra low-level counting setup has been installed in the
shallow-underground laboratory Felsenkeller in Dresden, Germany. It includes a
high-purity germanium detector (HPGe) of 163\% relative efficiency within
passive and active shields. The passive shield consists of 45m rock overburden
(140 meters water equivalent), 40 cm of low-activity concrete, and a lead and
copper castle enclosed by an anti-radon box. The passive shielding alone is
found to reduce the background rate to rates comparable to other
shallow-underground laboratories. An additional active veto is given by five
large plastic scintillation panels surrounding the setup. It further reduces
the background rate by more than one order of magnitude down to 1161
kg d in an energy interval of 40-2700 keV. This low background
rate is unprecedented for shallow-underground laboratories and close to deep
underground laboratories.Comment: Submitted to Astroparticle Physics; corrected typo in abstrac
Improved S factor of the 12C(p,γ)13N reaction at E=320–620 keV and the 422 keV resonance
The 12C(p,γ)13N reaction is the onset process of both the CNO and hot CNO cycles that drive massive star, red and asymptotic giant branch star, and novae nucleosynthesis. The 12C(p,γ)13N rate affects the final abundances of the stable 12,13C nuclides with ramifications for meteoritic carbon isotopic abundances and the s-process neutron source strength. Here, an underground measurement of the 12C(p,γ)13N cross section is reported. The present data, obtained at the Felsenkeller shallow-underground laboratory in Dresden (Germany), encompass the 320–620 keV center of mass energy range to include the wide and poorly constrained E=422 keV resonance that dominates the rate at high temperatures. This work's S-factor results, lower than literature by 25%, are included in a comprehensive R-matrix fit, and the energy of the 12+ first excited state of 13N is found to be 2369.6(4) keV with a radiative and proton width of 0.49(3) eV and 34.9(2) keV, respectively. A reaction rate, based on the present R-matrix fit and extrapolation, is suggested
Electric and magnetic dipole strength in Zn 66
The dipole strength of the nuclide Zn66 was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of energies of 7.5 and 13.4 MeV at the γELBE facility as well as using quasimonoenergetic and linearly polarized photon beams of 30 energies within the range of 4.3 to 9.9 MeV at the HIγS facility. A total of 128 J=1 states were identified, among them 9 with 1+ and 86 with 1- assignments. The quasicontinuum of unresolved transitions was included in the analysis of the spectra and the intensities of branching transitions were estimated on the basis of simulations of statistical γ-ray cascades. As a result, the photoabsorption cross section up to the neutron-separation energy was determined and compared with predictions of the statistical reaction model. The experimental M1 strengths from resolved 1+ states are compared with results of large-scale shell-model calculations
Destructive Divorce in the Family Life Cycle and its Implications: Criticisms of Parental Alienation
How Patients Communicate about their Illness
This article presents two empirical investigations of how patients communicate about their illness. A review of the literature on provider-patient communication is offered. From this review, we conclude that we know intuitively more about the interaction between health care providers and their patients than the research literature has revealed. A series of research questions are advanced concerning the patient\u27s communicative contributions to the provider-patient relationship. The first study offers evidence of distinct patient-communication typologies. How patients communicate about their illness is also closely related to how they utilize the health care system. The second study uses independent raters to validate patient self-reports about their communication behavior. The findings suggest that how patients communicate to health care providers is a factor worthy of further study. Several specific avenues for future research are discussed in light of these findings
Low-lying dipole strength distribution in 204Pb
Dipole and quadrupole strength distribution of 204Pb was investigated via a nuclear resonance fluorescence experiment using bremsstrahlung produced using an electron beam at a kinetic energy of 10.5 MeV at the linear accelerator ELBE. We identified 136 states resonantly excited at energies from 3.6 to 8.4 MeV. Spins of the excited states were deduced by angular distribution ratios of gamma rays observed at scattering angles of 90 and 127 degrees with respect to the incident gamma beam. The present experimental results were used to investigate the E1 transition probabilities by comparison with predictions from the quasiparticle-phonon model (QPM) with the self-consistent energy-density functional (EDF)
Measurement of the H2(p,γ)He3 S factor at 265–1094 keV
Recent astronomical data have provided the primordial deuterium abundance with percent precision. As a result, big bang nucleosynthesis may provide a constraint on the universal baryon to photon ratio that is as precise as, but independent from, analyses of the cosmic microwave background. However, such a constraint requires that the nuclear reaction rates governing the production and destruction of primordial deuterium are sufficiently well known. Here, a new measurement of the 2H(p,γ)3He cross-section is reported. This nuclear reaction dominates the error on the predicted big bang deuterium abundance. A proton beam of 400–1650 keV beam energy was incident on solid titanium deuteride targets, and the emitted γ rays were detected in two high-purity germanium detectors at angles of 55∘ and 90∘, respectively. The deuterium content of the targets has been obtained in situ by the 2H(3He,p)4He reaction and offline using the elastic recoil detection method. The astrophysical S factor has been determined at center of mass energies between 265 and 1094 keV, addressing the uppermost part of the relevant energy range for big bang nucleosynthesis and complementary to ongoing work at lower energies. The new data support a higher S factor at big bang temperatures than previously assumed, reducing the predicted deuterium abundance.peerReviewe
制動放射光を用いたPb-204の核共鳴蛍光散乱実験
安定な鉛原子核では、励起エネルギー10MeV以下に、電子双極子(E1)遷移に対する総和則の1%程度のE1強度が観測されており、核表面に現れる中性子スキンとの関連が指摘されている。Pb-204に対するこれまでの核共鳴蛍光散乱実験[1]では、励起エネルギー2.3から6.5MeVに45準位が観測されているが、6.5MeVから中性子放出のしきい値(8.4MeV)までの領域はよくわかっていない。そこで、本研究では、このエネルギー領域の共鳴準位を調べるため、最大エネルギー10.5MeVの制動放射光を用いて、Pb-204の核共鳴蛍光散乱実験を行った。日本原子力学会2021年秋の大
Photoexcitation of Ge
The dipole strength of the nuclide Ge76 was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of energies of 7.8 and 12.3 MeV delivered by the electron linear accelerator of high brilliance and high brightness (ELBE). We identified 210 levels up to an excitation energy of 9.4 MeV and assigned spin J = 1 to most of them. The quasicontinuum of unresolved transitions was included in the analysis of the spectra and the intensities of branching transitions were estimated on the basis of simulations of statistical γ-ray cascades. The photoabsorption cross section up to the neutron-separation energy was determined and is compared with predictions of the statistical reaction model. The derived photon strength function is compared with results of experiments using other reactions.The dipole strength of the nuclide Ge was studied in photon-scattering experiments using bremsstrahlung produced with electron beams of energies of 7.8 and 12.3 MeV at the ELBE facility. We identified 210 levels up to an excitation energy of 9.4 MeV and assigned spin = 1 to most of them. The quasicontinuum of unresolved transitions was included in the analysis of the spectra and the intensities of branching transitions were estimated on the basis of simulations of statistical -ray cascades. The photoabsorption cross section up to the neutron-separation energy was determined and is compared with predictions of the statistical reaction model. The derived photon strength function is compared with results of experiments using other reactions