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Abstract: The effect of collimation to the alpha-particle energy spectra was investigated for two different types of air filters, when the measurements were performed at ambient air pressure. Significant improvement of the energy resolution is possible if appropriate collimator is used. This is because only those alpha particles are detected entering the detector almost perpendicularly. We also show that although in-situ alpha spectrometry from air filters at ambient air pressure and with good energy resolution is possible, the accumulation of alpha-particle emitting aerosols in the surface of the collimator and the detector may deteriorate the registered spectrum. Therefore, the presence of possible spurious alpha peaks must be taken into account in continuous air monitoring. [Copyright &y& Elsevier]

Abstract: A Penning trap-based purification process having a resolution of about 1ppm is reported. In this context, we present for the first time a production method for the most complicated and crucially important nuclear weapons test signature, 133mXe. These pure xenon samples are required by the Comprehensive Nuclear-Test-Ban Treaty Organization to standardize and calibrate the worldwide network of xenon detectors. [Copyright &y& Elsevier]

Abstract: The decay of 133mXe has been re-measured using an electron-transporter spectrometer and a planar HPGe detector. The sample of 133mXe was produced by means of proton-induced fission using an ion-guide based on-line mass separator. The deduced K and L+M+… shell conversion coefficients, α Κ=6.5(9) and , agree within the uncertainty limits with the theoretical values and remove the inconsistencies between the previous experimental studies of 133mXe. [Copyright &y& Elsevier]

219Rn recoils from the alpha decay of 223Ra have been used to study the efficiency and delay time distributions of a gas-catcher/ion guide system. Ions with charge states up to +4 were coming out of the gas cell. Combining efficiency and delay time measurements, ion survival times in plasma free conditions can be deduced. [Copyright &y& Elsevier]

Abstract: Pure samples of 131mXe, 133mXe, 133Xe and 135Xe facilitate the calibration and testing of noble gas sampler stations and related laboratory instrumentation. We have earlier reported a Penning trap-based production method for pure 133mXe and 133Xe samples. Here we complete the work by reporting the successful production of pure 131mXe and 135Xe samples using the same technique. In addition, we present data on xenon release from graphite. [Copyright &y& Elsevier]

An electron spectrometry set-up was built at IRMM consisting of a vacuum chamber with a moveable source holder and windowless Peltier-cooled silicon drift detector (SDD). The SDD is well suited for measuring low-energy x rays and electrons emitted from thin radioactive sources with low self-absorption. The attainable energy resolution is better than 0.5 keV for electrons of 30 keV. It has been used to measure the conversion electron spectra of three plutonium isotopes, i.e. 238 Pu, 239 Pu, 240 Pu, as well as 241 Am (being a decay product of 241 Pu). The obtained mixed x-ray and electron spectra are compared with spectra obtained with a close-geometry set-up using another SDD in STUK and spectra measured with a Si(Li) detector at IRMM. The potential of conversion electron spectrometry for isotopic analysis of mixed plutonium samples is investigated. With respect to the 240 Pu/ 239 Pu isotopic ratio, the conversion electron peaks of both isotopes are more clearly separated than their largely overlapping peaks in alpha spectra. [ABSTRACT FROM AUTHOR]

Abstract: Aerosol samples have been studied under different background conditions using gamma-ray coincidence and low-background gamma-ray singles spectrometric techniques with High-Purity Germanium detectors. Conventional low-background gamma-ray singles counting is a competitive technique when compared to the gamma–gamma coincidence approach in elevated background conditions. However, measurement of gamma–gamma coincidences can clearly make the identification of different nuclides more reliable and efficient than using singles spectrometry alone. The optimum solution would be a low-background counting station capable of both singles and gamma–gamma coincidence spectrometry. [Copyright &y& Elsevier]

Abstract: The laser ion source at the IGISOL facility, Jyväskylä, has been used to study the effects of the passage of a primary beam through an ion guide via the dynamic time profiles of yttrium and related molecular compounds. The accessibility of a neutral fraction for laser ionization is shown to be restricted to the nozzle region in the presence of a weak plasma. The survival of this neutral fraction cannot be explained by recombination of the buffer gas alone and perhaps indicates a suppression of the transport of ions due to a plasma-generated electric field. The concept of a competition between the processes that create and destroy the ion of interest is used to explain the different trends in the ratio of yttrium to yttrium oxide following the extraction of a stopped primary beam of 89Y21+ in both helium and argon buffer gases. [Copyright &y& Elsevier]

Abstract: There is an increasing interest in using radioisotopes of rare earth elements for internal radiotherapy and for imaging in nuclear medicine. 177Lu is one of the promising radionuclides. This article reports on the first measurements of the excitation function for the production of 177Lu with proton-beam energies up to 17MeV on natural hafnium targets. The experimental cross sections for the reaction natHf(p,x)177Lu were obtained by the activation of a stacked-foil target and subsequent gamma spectrometry. Theoretical cross sections were calculated up to 35MeV with the EMPIRE nuclear reaction model code. The measured and calculated cross sections were used for deriving the thick-target yields and for estimating the production of other nuclides than 177Lu. Measured production cross sections of 175,176,177,178Ta on the same target are also presented. [Copyright &y& Elsevier]

The production of neutron-deficient krypton isotopes having astrophysical importance has been studied at the ISOLDE PBS facility at CERN. To investigate several effects on the yield a Monte Carlo code has been extensively applied. [Copyright &y& Elsevier]

Yields of He, Ne, Ar, Kr and Xe isotopic chains were measured from UCx/graphite and ThCx/graphite targets at the PSB-ISOLDE facility at CERN using isobaric selectivity achieved by the combination of a plasma-discharge ion source with a water-cooled transfer line.The delay times measured for a UCx/graphite target allow for an extrapolation to the expected yields of very neutron-rich noble gas isotopes, in particular for the “NuPECC reference elements” Ar and Kr, at the next-generation radioactive ion-beam facility EURISOL. [Copyright &y& Elsevier]

Beta-decay half-lives of two nuclei close to N=Z line, 70Kr and 74Rb, have been measured at the ISOLDE mass-separator facility at CERN. Importance of these half-lives on two ingredients explaining existence and development of the Universe, the astrophysical nucleosynthesis and the Standard Model, are discussed. [Copyright &y& Elsevier]

Abstract: Elemental production cross sections were measured for (p,x) reactions on natural Cu targets, leading to the formation of 62,63,65Zn. These reactions are generally used for monitoring the proton beam intensity and energy e.g. in isotope production facilities. Cross sections were obtained by activation of stacked foils and subsequent gamma spectroscopy. The production data for 62,63,65Zn between 7 and 16.5MeV proton energy are presented as well as comparisons with literature values. Good agreement with the evaluated values was found for most of the cross-section values. [Copyright &y& Elsevier]

The light collection efficiency of plastic scintillator panels used in radiation portal monitors (RPM) declines over time. We present an efficiency calibration procedure to measure the capability of an aged panel to detect 186 keV gamma rays of highly enriched uranium (HEU). The method is based on a coincidence measurement of backscattered Cs-137 gamma rays having an energy of 184 keV. Energy calibration of the plastic panel can be obtained from the same measurement. • A method to mimic highly enriched uranium (HEU) gamma rays with Cs-137 is presented. • Method is suited for analysing the performance of old plastic radiation portal monitors (RPM). • Plastic portal monitor efficiency and energy calibration are obtained with a single measurement. [ABSTRACT FROM AUTHOR]