Gas Purity effect on GEM Performance in He and Ne at Low Temperatures

The performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne, He+H2 and Ne+H2 was studied at temperatures in the range of 3-293 K. This paper reports on previously published measurements and additional studies on the effects of the purity of the gases in which the GEM performance is evaluated. In He, at temperatures between 77 and 293 K, triple-GEM structures operate at rather high gains, exceeding 1000. There is an indication that this high gain is achieved through the Penning effect as a result of impurities in the gas. At lower temperatures the gain-voltage characteristics are significantly modified probably due to the freeze-out of these impurities. Double-GEM and single-GEM structures can operate down to 3 K at gains reaching only several tens at a gas density of about 0.5 g/l; at higher densities the maximum gain drops further. In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in Ne at low temperatures can be re-established in Penning mixtures of Ne+H2: very high gains, exceeding 104, have been obtained in these mixtures at 30-77 K, at a density of 9.2 g/l which corresponds to saturated Ne vapor density at 27 K. The addition of small amounts of H2 in He also re-establishes large GEM gains above 30 K but no gain was observed in He+H2 at 4 K and a density of 1.7 g/l (corresponding to roughly one-tenth of the saturated vapor density). These studies are, in part, being pursued in the development of two-phase He and Ne detectors for solar neutrino detection.Comment: 4 pages, 7 figure

Not fitting in and getting out : psychological type and congregational satisfaction among Anglican churchgoers in England

Listening to the motivations reported by individuals for ceasing church attendance and becoming church leavers, Francis and Richter identified high on the list the sense of "not fitting in". Drawing on psychological type theory, several recent studies have documented the way in which some psychological types are over-represented in church congregations and other psychological types are under-represented. Bringing these two observations together, the present study tested the hypothesis that church congregations have created type-alike communities within which individuals displaying the opposite type preferences are more likely to feel marginalised and to display lower levels of satisfaction with the congregations they attend. Data were provided by 1867 churchgoers who completed a measure of psychological type, together with measures of frequency of attendance and congregational satisfaction. These data confirmed that congregations were weighted towards preferences for introversion, sensing, feeling and judging, and that individuals displaying the opposite preferences (especially intuition, thinking and perceiving) recorded lower levels of congregational satisfaction. The implications of these findings are discussed for promoting congregational retention by enhancing awareness of psychological type preferences among those who attend

GEM operation in helium and neon at low temperatures

We study the performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne and Ne+H2 at temperatures in the range of 2.6-293 K. In He, at temperatures between 62 and 293 K, the triple-GEM structures often operate at rather high gains, exceeding 1000. There is an indication that this high gain is achieved by Penning effect in the gas impurities released by outgassing. At lower temperatures the gain-voltage characteristics are significantly modified probably due to the freeze-out of impurities. In particular, the double-GEM and single-GEM structures can operate down to 2.6 K at gains reaching only several tens at a gas density of about 0.5 g/l; at higher densities the maximum gain drops further. In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in Ne at low temperatures can be reestablished in Penning mixtures of Ne+H2: very high gains, exceeding 10000, have been obtained in these mixtures at 50-60 K, at a density of 9.2 g/l corresponding to that of saturated Ne vapor near 27 K. The results obtained are relevant in the fields of two-phase He and Ne detectors for solar neutrino detection and electron avalanching at low temperatures.Comment: 13 pages, 14 figures. Accepted for publishing in Nucl. Instr. and Meth.

Optical properties of pyrochlore oxide Pb2Ru2O7−δPb_{2}Ru_{2}O_{7-{\delta}}

We present optical conductivity spectra for $Pb_{2}Ru_{2}O_{7-{\delta}}$ single crystal at different temperatures. Among reported pyrochlore ruthenates, this compound exhibits metallic behavior in a wide temperature range and has the least resistivity. At low frequencies, the optical spectra show typical Drude responses, but with a knee feature around 1000 \cm. Above 20000 \cm, a broad absorption feature is observed. Our analysis suggests that the low frequency responses can be understood from two Drude components arising from the partially filled Ru $t_{2g}$ bands with different plasma frequencies and scattering rates. The high frequency broad absorption may be contributed by two interband transitions: from occupied Ru $t_{2g}$ states to empty $e_{g}$ bands and from the fully filled O 2p bands to unoccupied Ru $t_{2g}$ states.Comment: 4 pages, 6 figure

Congregational bonding social capital and psychological type : an empirical enquiry among Australian churchgoers

This study explores the variation in levels of bonding social capital experienced by individual churchgoers, drawing on data generated by the Australian National Church Life Survey, and employing a five-item measure of church-related bonding social capital. Data provided by 2065 Australian churchgoers are used to test the thesis that individual differences in bonding social capital are related to a psychological model of psychological types (employing the Jungian distinctions). The data demonstrated that higher levels of bonding social capital were found among extraverts (compared with introverts), among intuitive types (compared with sensing types) and among feeling types (compared with thinking types), but no significant differences were found between judging types and perceiving types

New, high statistics measurement of the K+ -> pi0 e+ nu (Ke3) branching ratio

E865 at the Brookhaven National Laboratory AGS collected about 70,000 K+(e3) events with the purpose of measuring the relative K+(e3) branching ratio. The pi0 in all the decays was detected using the e+e- pair from pi0 -> e+e-gamma decay and no photons were required. Using the Particle Data Group branching ratios for the normalization decays we obtain BR(K+(e3(gamma))=(5.13+/-0.02(stat)+/-0.09(sys)+/-0.04(norm))%, where $K+(e3(gamma)) includes the effect of virtual and real photons. This result is 2.3 sigma higher than the current Particle Data Group value. The implications of this result for the$V_{us}$ element of the CKM matrix, and the matrix's unitarity are discussed.Comment: 4 pages, 5 figures; final version accepted by PR

Experimental Study of the Radiative Decays K+ -> mu+ nu e+e- and K+ -> e+ nu e+e-

Experiment 865 at the Brookhaven AGS obtained 410 K+ -> e+ nu e+e- and 2679 K+ -> mu+ nu e+e- events including 10% and 19% background. The branching ratios were measured to be (2.48+-0.14(stat.)+-0.14(syst.))x10^-8 (m_ee>150 MeV) and (7.06+-0.16+-0.26)x10^-8 (m_ee>145 MeV), respectively. Results for the decay form factors are presented.Comment: 4 pages, 3 figures, RevTeX

Low-mass e+e- pair production in 158 A GeV Pb-Au collisions at the CERN SPS, its dependence on multiplicity and transverse momentum

We report a measurement of low-mass electron pairs observed in 158 GeV/nucleon Pb-Au collisions. The pair yield integrated over the range of invariant masses 0.2 < m < 2.0 GeV is enhanced by a factor of 3.5 +/- 0.4 (stat) +/- 0.9 (syst) over the expectation from neutral meson decays. As observed previously in S-Au collisions, the enhancement is most pronounced in the invariant-mass region 300-700 MeV. For Pb-Au we find evidence for a strong increase of the enhancement with centrality. In addition, we show that the enhancement covers a wide range in transverse momentum, but is largest at the lowest observed pt.Comment: 17 pages, 4 figures, submitted to Phys.Lett.

First observation of the decay K+ -> e+ nu mu+ mu-

Experiment 865 at the Brookhaven AGS has observed the decay K^+ -> e^+ nu mu^+ mu^-. The branching ratio extracted is (1.72 +/- 0.37(stat) +/- 0.17(syst) +/- 0.19(model)) x 10^{-8} where the third term in the error results from the use of a model to extrapolate into a kinematic region dominated by background.Comment: 4 pages, 6 figures, Revtex4. Correction to figure and minor text change