Kr Source Research Articles

A magnetically enhanced RF discharge source for metastable krypton production.

We describe a high intensity metastable Kr source based on a helical resonator RF discharge. By adding an external B-field to the discharge source, the metastable Kr flux is enhanced. The effect of geometric configuration and magnetic field strength has been studied and optimized experimentally. Compared to the helical resonator discharge source without an external B-field, the new source showed an enhancement factor of 4-5 in producing metastable Kr beams. This improvement has a direct impact on the radio-krypton dating applications as it can increase the atom count rate, resulting in a higher analytical precision.

A dual-phase xenon TPC for scintillation and ionisation yield measurements in liquid xenon

A small-scale, two-phase (liquid/gas) xenon time projection chamber (Xurich II) was designed, constructed and is under operation at the University of Zürich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal ^{83mathrm {m}}Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200 upmu s. The relative energy resolution, sigma /E, is 11.9 and 5.8% at 9.4 and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.

The L/K electron capture ratio in first-forbidden 81gKr decay

The L/K electron capture (EC) ratio of 81g Kr was measured to be 0.146±0.005 utilizing the wall-less, anticoincidence, multiwire proportional counter technique and a reactor-produced, mass separated 81g Kr source. From this value, the Q EC and log ft values were determined to be 305 −29 +38 keV and 11.6 respectively, assuming EC decay only to the ground state. If there is 4 % EC branching to a reported 276 keV level, Q EC becomes 322 −14 +31 keV from which (L/K) g.s. = 0.144 ± 0.005, log ft = 11.6 for EC to the ground state, (L/K) 276 = 0.213±0.005, and log ft = 11.4 for 4 % feeding to the 276 keV level. In order to be confident of these results, an extensive systematic comparison of experimental and theoretical L/K ratios was made for both first-forbidden non-unique and unique transitions. From this comparison, a 7 2 + ground state assignment for 81 Kr is confirmed.

Radiation-Induced Polymerization of Acrylamide in Aqueous Solution Using 85Kr Source (II)

Radiation-Induced Polymerization of Acrylamide in Aqueous Solution Using ⁸⁵Kr Source (II)

Radiation-Induced Polymerization of Acrylamide in Aqueous Solution Using 85Kr Source, (I)

Radiation-Induced Polymerization of Acrylamide in Aqueous Solution Using ⁸⁵Kr Source, (I)

Mössbauer recoilless fraction of solid krypton

The Mössbauer recoilless fraction is measured by using solid Kr sources and absorbers over a temperature range 5–85°K. Experimental recoilless fractions are compared with theoretical values.