Magnetic microcalorimeter with paramagnetic temperature sensors and integrated dc-SQUID readout for high-resolution X-ray emission spectroscopy

We present two variants of a magnetic microcalorimeter with paramagnetic temperature sensors and integrated dc-SQUID readout for high-resolution X-ray emission spectroscopy. Each variant employs two overhanging gold absorbers with a sensitive area of 150$\mu$m x 150$\mu$m and a thickness of 3$\mu$m, thus providing a quantum efficiency of 98% for photons up to 5keV and 50% for photons up to 10keV. The first variant turned out to be fully operational, but, at the same time, to suffer from Joule power dissipation of the Josephson junction shunt resistors, athermal phonon loss, and slew rate limitations of the overall setup. Overall, it only achieved an energy resolution $\Delta E_\mathrm{FWHM} = 8.9eV$. In the second variant, we introduced an innovative `tetrapod absorber geometry' as well as a membrane-technique for protecting the temperature sensors against the power dissipation of the shunt resistors. By this, the second variant achieves an outstanding energy resolution of $\Delta E_\mathrm{FWHM} =1.25(18)eV$ and hence provides, to our knowledge, the present best energy resolving power $E/\Delta E_\mathrm{FWHM}$ among all existing energy-dispersive detectors for soft and tender X-rays.Comment: submitted to Applied Physics Letter

Adding Value: Certified Coffee Trade in North America

Coffee is the leading agricultural sector in terms of both the number and frequent use of social and environmental certification. This fast-growing category of certified sustainable coffees has emerged from almost negligible quantities in the late 1990s to approximately 4% of global green coffee exports in 2006 making it a multi-billion dollar segment of the industry. The US and Canada account for over one quarter of global coffee imports in value. Their consumers are increasingly attentive to the social, economic, and environmental aspects of coffee production as evidenced by the significant expansion of certified coffees into both gourmet and mass market channels. This chapter covers the market development and current statistics of all the certified sustainable coffees in North America including volumes, value, premiums, and their general trends at the global level.organic; fair trade; eco-friendly; Rainforest Alliance; Utz; certified; coffee; commodities; supply chain; sustainable; markets

Adding Value: Certified Coffee Trade in North America

Coffee is the leading agricultural sector in terms of both the number and frequent use of social and environmental certification. This fast-growing category of certified sustainable coffees has emerged from almost negligible quantities in the late 1990s to approximately 4% of global green coffee exports in 2006 making it a multi-billion dollar segment of the industry. The US and Canada account for over one quarter of global coffee imports in value. Their consumers are increasingly attentive to the social, economic, and environmental aspects of coffee production as evidenced by the significant expansion of certified coffees into both gourmet and mass market channels. This chapter covers the market development and current statistics of all the certified sustainable coffees in North America including volumes, value, premiums, and their general trends at the global level

Beta spectrometry with metallic magnetic calorimeters in the framework of the EU EMPIR project METROBETA

International audienceMetroBeta is a European EMPIR (European Metrology Programme for Innovation and Research) project aiming at the improvement of the knowledge of the shapes of beta spectra, both in terms of theoretical calculation and measurement. In this context, metallic magnetic calorimeters (MMCs), cryogenic detectors operated at very low temperature (below 20 mK), have been developed for the precise measurement of the shapes of beta spectra. MMCs with the beta emitter embedded in a metallic particle absorber has already proven to be among the best beta spectrometers, in particular for low energy beta transitions. Since the MMCs must be designed specifically to match the absorber heat capacity for optimal energy sensitivity, within this project several MMC designs have been optimized for the absorber sizes required for the measurement of beta spectra with Q values ranging from a few tens of keV up to ~ 1 MeV. Four spectra from mostly pure beta emitters will be measured within the project: Sm-151 (Q = 76.3 keV, the only one of the radionuclides having a small beta decay branch to an excited state), C-14 (Q = 156.5 keV), Tc-99 (Q = 293.8 keV) and Cl-36 (Q = 709.5 keV). Intense research and development work was devoted to the fabrication of high quality sources for each of the radionuclides and their integration within the MMC absorbers. This particular study is of utmost importance since previously it had been observed that the spectra measured with sources composed of a salt can be considerably distorted due to the loss of a fraction of the beta energy in the salt which is then not fully converted to heat. Another study concerning the composition of the absorbers is still ongoing. For low energy spectra, simple gold or silver absorbers can be used. However, spectra with Q values higher than ~ 500 keV can be distorted by the escape of Bremsstrahlung from the absorber. Monte Carlo simulations were performed to study the influence of the absorber material and the usefulness of composite absorbers to minimize this source of spectrum distortion. A series of measurements is currently under preparation to explore the optimum source-absorber configuration for the beta spectrum of Cl-36. he comparison of the measured spectra with the theoretical spectra calculated with the advanced code BetaShape, which is being further developed within the project, will be presented

Experimental study of x-distributions in semileptonic neutral-current neutrino reactions

Neutral-current differential cross sections as a function of the scaling variable x for deep inelastic neutrino-nucleon and antineutrino-nucleon scattering on an isoscalar target were measured in the CERN SPS 200 GeV/c Narrow-Band Beam with the CHARM fine-grained calorimeter. The data have been corrected for the experimental resolutions using a novel unfolding procedure. Its validity is tested on charged-current reactions. The x-distributions determined in neutral-current reactions are found to be compatible with the results obtained in charged-current reactions, as expected by the quark model of the nucleon and by the standard model of the weak interactions

Experimental study of x-distributions in semileptonic neutral-current neutrino reactions

Neutral-current differential cross sections as a function of the scaling variable x for deep inelastic neutrino-nucleon and antineutrino-nucleon scattering on an isoscalar target were measured in the CERN SPS 200 GeV/c Narrow-Band Beam with the CHARM fine-grained calorimeter. The data have been corrected for the experimental resolutions using a novel unfolding procedure. Its validity is tested on charged-current reactions. The x-distributions determined in neutral-current reactions are found to be compatible with the results obtained in charged-current reactions, as expected by the quark model of the nucleon and by the standard model of the weak interactions