The Half-lives of 132^{132}La and 135^{135}La

The half-lives of $^{135}$La and $^{132}$La were determined via gamma spectroscopy and high-precision ionization chamber measurements. The results are 18.930(6) h for $^{135}$La and 4.59(4) h for $^{132}$La compared to the previously compiled values of 19.5(2) h and 4.8(2) h, respectively. The new results represent an improvement in the precision and accuracy of both values. These lanthanum isotopes comprise a medically interesting system with positron emitter $^{132}$La and Auger electron emitter $^{135}$La forming a matched pair for internal diagnostics and therapeutics. The precise half-lives are necessary for proper evaluation of their value in medicine and for a more representative tabulation of nuclear data.Comment: 11 pages, 3 figure

Hybridly pumped collisional soft X-ray laser in Ne-like sulphur

Includes bibliographical references (page 98).We describe an experiment demonstrating XUV amplification following collisional excitation in a discharge-created plasma waveguide irradiated by a picosecond optical laser pulse. A capillary discharge was used to generate a plasma radiation pipe with a radially concave electron density profile. Temporally resolved transmission characteristics and guiding effect have been measured. An intense short laser pulse rapidly heated the electrons, producing amplification in the 3p1S0-3s 1P1 transition of Ne-like S at 60.84 nm. The integrated gain-length product obtained within a 3 cm active medium with a laser energy of 0.46 J was ~6.8. The pump energy depletion has been analysed as well. This new, hybridly pumped soft X-ray laser with the transient gain offers a new way towards efficient tabletop coherent XUV sources

Demonstration of a hybrid collisional soft-x-ray laser

Includes bibliographical references (pages 033803-4-033803-5).We report on a demonstration of x-ray-ultraviolet amplification following collisional excitation in a discharge-created plasma waveguide irradiated by a picosecond optical laser pulse. A capillary discharge was used to generate a sulfur plasma column with a large concentration of Ne-like ions and a radially concave electron density profile. The intense short laser pulse rapidly heated the electrons, producing amplification in the 3p 1S0-3s 1P1 transition of Ne-like S at 60.8 nm. The integrated gain-length product obtained exciting a 3-cm-long capillary with a 0.46-J short laser pulse is 6.8. The beam divergence was observed to decrease as a function of plasma column length, reaching 2.5 mrad for 30-mm-long capillaries. This hybrid laser pumping scheme could lead to a new generation of efficient tabletop soft-x-ray lasers

Fast capillary discharge plasma as a preformed medium for longitudinally pumped collisional x-ray lasers

Includes bibliographical references (pages 219-220).Simulations of plasma dynamics in a fast capillary discharge are presented. The temporal dependence of the plasma column's resistance validates the one-dimensional model that was used in the numerical simulations. Numerical analysis of the laser absorption determines the pump parameter range for efficient excitation of longitudinally pumped transient collisional x-ray lasers

The Astrophysical Reaction Rate for the 18F(p,α) 15O Reaction

Proton and alpha widths for a 3/2+ ( l p = 0) state in 19Ne at Ex-7.1 MeV have been extracted using the results of recent measurements of the 18F(p,α)15O reaction. This l p = 0 resonance dominates the astrophysical reaction rates at temperatures T9\u3e0.5

Time resolution of the plastic scintillator strips with matrix photomultiplier readout for J-PET tomograph

Recent tests of a single module of the Jagiellonian Positron Emission Tomography system (J-PET) consisting of 30 cm long plastic scintillator strips have proven its applicability for the detection of annihilation quanta (0.511 MeV) with a coincidence resolving time (CRT) of 0.266 ns. The achieved resolution is almost by a factor of two better with respect to the current TOF-PET detectors and it can still be improved since, as it is shown in this article, the intrinsic limit of time resolution for the determination of time of the interaction of 0.511 MeV gamma quanta in plastic scintillators is much lower. As the major point of the article, a method allowing to record timestamps of several photons, at two ends of the scintillator strip, by means of matrix of silicon photomultipliers (SiPM) is introduced. As a result of simulations, conducted with the number of SiPM varying from 4 to 42, it is shown that the improvement of timing resolution saturates with the growing number of photomultipliers, and that the 2 x 5 configuration at two ends allowing to read twenty timestamps, constitutes an optimal solution. The conducted simulations accounted for the emission time distribution, photon transport and absorption inside the scintillator, as well as quantum efficiency and transit time spread of photosensors, and were checked based on the experimental results. Application of the 2 x 5 matrix of SiPM allows for achieving the coincidence resolving time in positron emission tomography of $\approx$ 0.170 ns for 15 cm axial field-of-view (AFOV) and $\approx$ 0.365 ns for 100 cm AFOV. The results open perspectives for construction of a cost-effective TOF-PET scanner with significantly better TOF resolution and larger AFOV with respect to the current TOF-PET modalities.Comment: To be published in Phys. Med. Biol. (26 pages, 17 figures

Nuclear Reaction Studies with Radioactive {sup 18}F Beams at ATLAS

The contribution of the {sup 18}F(p,{gamma}) reaction to the production of {sup 19}Ne which is the crucial isotope for the breakout from the hot CNO cycle into the rp process, has been investigated in experiments with {sup 18}F beams. Measurements of the cross sections for the {sup 18}F(p,{alpha}){sup 15}O and the {sup 18}F(p,{gamma}){sup 19}Ne reactions indicate that the contribution from the (p,{gamma}) route to the formation of {sup 19}Ne is small

The Influence of {sup 18} F Induced Reactions in the Hot CNO Cycle

The contribution of the {sup 18}F(p,{gamma}) reaction to the production of {sup 19}Ne, which is an important isotope in connection with the breakout from the hot CNO cycle, has been investigated in experiments with {sup 18}F beams. Measurements of the cross sections for the {sup 18}F(p,{alpha}){sup 15}O and {sup 18}F(p,{gamma}){sup 19 }Ne reactions indicate that the contribution of the {sup 18}F(p, {gamma}) route to the formation or {sup 19}Ne is small