Neutron-induced γ -ray production cross sections for the first excited-state transitions in 20 Ne and 22 Ne

Background: Neutron-induced reactions are a significant concern for experiments that require extremely low levels of radioactive backgrounds. Measurements of gamma-ray production cross sections over a wide energy range will help to predict and identify neutron backgrounds in these experiments. Purpose: Determine partial gamma-ray production cross sections for neutron-induced reactions in natural neon. Methods: The broad-spectrum neutron beam at the Los Alamos Neutron Science Center (LANSCE) was used for the measurement. Gamma rays from neutron-induced reactions were detected using the GErmanium Array for Neutron Induced Excitations (GEANIE). Results: Partial gamma-ray cross sections were measured for the first excited-state transitions in Ne-20 and Ne-22. The measured cross sections were compared to the TALYS and CoH3 nuclear reaction codes. Conclusions: These are the first experimental data for (n,n') reactions in neon. In addition to providing data to aid in the prediction and identification of neutron backgrounds in low-background experiments, these new measurements will help refine cross-section predictions in a mass region where models are not well constrained

The Majorana experiment: an ultra-low background search for neutrinoless double-beta decay

The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.Comment: Presentation for the Rutherford Centennial Conference on Nuclear Physic

The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76-Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76-Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76-Ge neutrinoless double-beta decay Q-value of 2039 keV.Comment: Submitted to AIP Conference Proceedings, 19th Particles & Nuclei International Conference (PANIC 2011), Massachusetts Institute of Technology, Cambridge, MA, USA, July 24-29, 2011; 3 pages, 1 figur

Planck Intermediate Results II: Comparison of Sunyaev-Zeldovich measurements from Planck and from the Arcminute Microkelvin Imager for 11 galaxy clusters

A comparison is presented of Sunyaev-Zeldovich measurements for 11 galaxy clusters as obtained by Planck and by the ground-based interferometer, the Arcminute Microkelvin Imager. Assuming a universal spherically-symmetric Generalised Navarro, Frenk & White (GNFW) model for the cluster gas pressure profile, we jointly constrain the integrated Compton-Y parameter (Y_500) and the scale radius (theta_500) of each cluster. Our resulting constraints in the Y_500-theta_500 2D parameter space derived from the two instruments overlap significantly for eight of the clusters, although, overall, there is a tendency for AMI to find the Sunyaev-Zeldovich signal to be smaller in angular size and fainter than Planck. Significant discrepancies exist for the three remaining clusters in the sample, namely A1413, A1914, and the newly-discovered Planck cluster PLCKESZ G139.59+24.18. The robustness of the analysis of both the Planck and AMI data is demonstrated through the use of detailed simulations, which also discount confusion from residual point (radio) sources and from diffuse astrophysical foregrounds as possible explanations for the discrepancies found. For a subset of our cluster sample, we have investigated the dependence of our results on the assumed pressure profile by repeating the analysis adopting the best-fitting GNFW profile shape which best matches X-ray observations. Adopting the best-fitting profile shape from the X-ray data does not, in general, resolve the discrepancies found in this subset of five clusters. Though based on a small sample, our results suggest that the adopted GNFW model may not be sufficiently flexible to describe clusters universally.Comment: update to metadata author list onl

Extraction of cluster parameters with future Sunyaev-Zel'dovich observations

The Sunyaev-Zel'dovich (SZ) effect of galaxy clusters is characterized by three parameters: Compton parameter, electron temperature and cluster peculiar velocity. In the present study we consider the problem of extracting these parameters using multi-frequency SZ observations only. We show that there exists a parameter degeneracy which can be broken with an appropriate choice of frequencies. As a result we discuss the optimal choice of observing frequencies from a theoretical point of view. Finally, we analyze the systematic errors (of the order micro K) on the SZ measurement introduced by finite bandwidths, and suggest a possible method of reducing these errors.Comment: 20 pages, 13 figures, to be published in JCA

Parasites and Raven Mothers: A German-Japanese Comparison on (Lone) Motherhood

Having a child out of wedlock used to be associated with shame and scorn. This is mostly not the case anymore in the western world. Therefore, freed from social sanctions, single motherhood has become an additional family-choice alternative for women, along with marriage and childlessness. Yet, the institutions that influence women's decisions differ across countries. We compare the institutional frame, in particular labor-market characteristics and family law, in Germany and Japan and, in addition, the interaction between culture and institutions. Both countries had a very traditional (one-earner) family system until the second half of the 20th century. Now we can observe that social changes that happened in Germany decades ago are happening only now in Japan. We analyze if and how the consequences in terms of family structures and fertility rates that resulted in Germany can be transfered to Japan.Dieser Artikel vergleicht die institutionellen Rahmenbedingungen in Deutschland und Japan, die die Fertilitätsentscheidung von Frauen beeinflussen können. Wir richten unser Augenmerk speziell auf Familienrecht, Arbeitsmarktcharakteristika und die Interaktion zwischen Institutionen und kulturellen Faktoren. Daraus leiten wir Implikationen für die relative Attraktivität von Ehe und Mutterschaft in beiden Ländern ab. Wir stellen fest, dass soziale Veränderungen, die in Deutschland vor einigen Jahrzenten vor sich gingen - insbesondere die Aufweichung der traditionellen Alleinverdiener-Familie - in Japan derzeit passieren. Wir analysieren, ob sich die Konsequenzen für Familienstruktur und Geburtenrate von Deutschland auf Japan übertragen lassen

Sunyaev-Zel'dovich Effect Observations of the Bullet Cluster (1E 0657-56) with APEX-SZ

We present observations of the Sunyaev-Zel'dovich effect (SZE) in the Bullet cluster (1E 0657--56) using the APEX-SZ instrument at 150 GHz with a resolution of 1 arcmin. The main results are maps of the SZE in this massive, merging galaxy cluster. The cluster is detected with 23 sigma significance within the central 1 arcmin radius of the source position. The SZE map has a broadly similar morphology to that in existing X-ray maps of this system, and we find no evidence for significant contamination of the SZE emission by radio or IR sources. In order to make simple quantitative comparisons with cluster gas models derived from X-ray observations, we fit our data to an isothermal elliptical beta model, despite the inadequacy of such a model for this complex merging system. With an X-ray derived prior on the power-law index, beta = 1.04 +0.16 -0.10, we find a core radius r_c =142 +/- 18 arcsec, an axial ratio of 0.889 +/- 0.072, and a central temperature decrement of -771 +/- 71 micro-K_CMB, including a +/-5.5% flux calibration uncertainty. Combining the APEX-SZ map with a map of projected electron surface density from Chandra X-ray observations, we determine the mass-weighted temperature of the cluster gas to be T_mg=10.8 +/- 0.9 keV, significantly lower than some previously reported X-ray spectroscopic temperatures. Under the assumption of an isothermal cluster gas distribution in hydrostatic equilibrium, we compute the gas mass fraction for prolate and oblate spheroidal geometries and find it to be consistent with previous results from X-ray and weak lensing observations. This work is the first result from the APEX-SZ experiment, and represents the first reported scientific result from observations with a large array of multiplexed superconducting transition-edge sensor bolometers.Comment: 17 pages, 5 figures, accepted for publication in the Astrophysical Journal. Changes in v2: Modified in response to referee comments. Also, improvements in the analysis pipeline and flux calibration result in modification of the maps and model fit parameters. Calibration section and X-ray comparison sections are significantly modifie