[en] The evolution of magnetism and superconductivity in Ce_2Rh_1_−_xPd_xIn_8 solid solutions has been studied within the entire concentration range by means of thermodynamic and magnetic measurements at ambient pressure and at temperatures between 0.35 K and room temperature. For this purpose, single crystals with Pd concentrations x=0, 0.10, 0.15, 0.30, 0.45, 0.55, 0.85 and 1 have been grown from In self-flux and characterized by x-ray diffraction and microprobe analysis. Starting from the antiferromagnet Ce_2RhIn_8, the Néel temperature gradually decreases with increasing Pd concentration and the antiferromagnetism has disappeared for x≥0.45. Superconductivity has been observed only for Ce_2PdIn_8

[en] Present status of the experiment TGV 11 which is devoted to the measurement of double-beta decay of ¹⁰⁶Cd is given. The low background spectrometer TGV II is installed in the Modane Underground Laboratory and has been running from February 2005 with approx. 10 grams of ¹⁰⁶Cd enriched at 75%. After an analysis of 3736 hours of experimental data the new improved half-life limit for 2νEC/EC decay of ¹⁰⁶Cd (0_g.s.⁺ → 0_g.s.⁺) is given as T_1/2^2ν > 4.8 x 10¹⁹ years (90% CL). The search for 2νEC/EC decay of ¹⁰⁶Cd to the excited states of ¹⁰⁶Pb allows to determine the limits of the half-lives T_1/2^2ν (0_g.s.⁺ → 2₁⁺) > 3.9 x 10¹⁹ years (90% CL) and T_1/2^2ν (0_g.s.⁺ → 0₁⁺) > 5.8 x 10¹⁹ years (90% CL). (author)

[en] Present status of experiments TGV I and TGV II is given. The TGV I collaboration has studied the double-beta decay of ⁴⁸Ca with a low-background and high sensitivity Ge multi-detector spectrometer TGV (Telescope Germanium Vertical). The preliminary results of T_1/2^2νββ = (4.2 (+3.3) (-1.3)) x 10¹⁹ years and T_1/2^0νββ > 1.5 x 10²¹ years (90% CL) for double-beta decay of ⁴⁸Ca has been found after the processing of experimental data obtained after 8700 hours of measuring time using approximately 1 gram of ⁴⁸Ca. The aim of the experiment TGV II is the development of the experimental methods, construction of spectrometers and measurement of the ββ decay (β⁺β⁺, β⁺ /EC, EC/EC) of ¹⁰⁶Cd particularly the 2νEC/EC mode. The theoretical description and performance of the TGV II spectrometer are also given. (author)

[en] An apparatus developed for the measurement of radon diffusion through thin foils for the SuperNEMO project is presented. The goal of the SuperNEMO collaboration is to construct a new generation detector for the search for neutrinoless double-beta decay (0νββ) with 100 kg of enriched isotope as the source. At present, the collaboration is carrying out R and D in order to suppress significantly intrinsic background including that caused by radon. The description of the apparatus, data analysis method, as well as the results obtained in the measurement of radon diffusion through several types of thin foils, glue and sealant suitable for shielding in the SuperNEMO detector are discussed.

[en] In this work we investigate the effect of pressure on the rotational temperature of N₂ in the RF discharge plasma. Optimal pressure for the ionization has been found by analyzing spectra of the First negative system and the Second positive system. Detection was carried out in the newly built detection system based on CCD. (Authors)

[en] We present an experimental setup incorporating a Cavity ring-down spectrometer that enables detection of particles with high sensitivity. The performance of the system is demonstrated. We designed and constructed the spectrometer using a diode laser so that it is comparable with setups employing expensive lasers. Cavity ring-down spectrometer application in plasma physics are outlined. (Authors)

[en] A new PICASSO droplet detector is under development for its installation at the Sudbury Neutrino Observatory (SNO). The concept of the PICASSO experiment rests on an approach consisting of the detection of Cold Dark Matter (CDM) candidate particles, the neutralino in particular, through the use of large mass superheated droplet modular detectors. The sources of background signal for PICASSO detector are gamma rays, mips's, neutrons, radon and alpha particles due to U/Th contamination of the detector and its environment. Droplet detectors have high efficiency for detecting neutrons while being insensitive to mip's, gamma rays when operated at proper temperature and pressure. As in the case of other low background experiments radon is a very important source of background. Radon can diffuse into the detector during fabrication, storage, operation and induce an alpha background by its disintegration. The purpose of our long-term measurement was to define the tightness and penetrability of the PICASSO emulsion container against radon. The PICASSO box has been placed into a bigger plastic box and a Si detector has been installed in both boxes. The source of radon (pitchblende) has been inserted into an outer plastic box to obtain a high level radon environment. Radon monitoring was based on an electrostatic collection of its progeny ²¹⁸Po and ²¹⁴Po on the Si detector entrance window with spectroscopic counting of alpha particles (e.g. [2]). The spectrometer TAIP was used for a particle energy measurement. The spectrometer was developed at the Czech Technical University in Prague. The spectrometer contains all the spectrometric modules needed for energy measurement as well as the source of voltage for Si detector. It also includes digital memory to save spectra during measurement (up to 1792 spectra). Two long-time tests (2 months and 2.5 months) were performed. Radon concentrations in both containers (the outer plastic box, the PICASSO container) have been measured. The saturated ratio of both values determines the penetrability of the PICASSO emulsion container. The radon suppression factor of the PICASSO emulsion container was calculated to be 10⁵. (author)

[en] We report on specific-heat measurements of the heavy-fermion compounds Ce_1-xY_xPdAl (0 ≤ x ≤ 1) between 0.35 and 300 K and in magnetic fields up to 14 T. Ce_1-xY_xPdAl compounds crystallize in the hexagonal ZrNiAl-type structure and CePdAl orders antiferromagnetically below T_N = 2.8 K. The specific heat measured in external magnetic fields is also consistent with the antiferromagnetic order and the phase transition to the ferromagnetic state in fields around 4 T. The temperature dependence of the magnetic specific heat in CePdAl indicates magnetic correlations far above T_N. Substitution of nonmagnetic Y for magnetic Ce ions reduces T_N rapidly and the antiferromagnetic order vanishes around x = 0.2. The Sommerfeld coefficient γ of the electronic specific heat is temperature dependent and increases strongly at low temperatures for all Ce concentrations.

[en] CeCu_0.7Al_3.3 single crystals have been prepared by the solution growth method. The compound crystallizes in the tetragonal BaAl₄-type of structure with lattice parameters a=4.262 Aand c=10.776 A. A detailed specific-heat study of CeCu_0.7Al_3.3 is presented. The data confirm ferromagnetic order below T_C=4 K. The estimated Kondo temperature lies also around 4 K. The electronic specific-heat coefficient was found to be moderately enhanced over the values for common metallic compounds. It is shown that the energy splitting between the ground state and the first excited doublet amounts to 75 K at least, which is considerably higher than the value deduced from magnetization data.

[en] The aim of the study was experimental quantification of Cu, Zn and Pb bioleaching from solid substrates of mining wastes using microorganisms, including evaluation of extraction efficiency of selected elements, quantification of their bioaccumulation using autochthonous microbiota enriched with Aspergillus niger and Neosartorya fischeri strains to increase process efficiency. The experiments were performed on native samples of flotation sludge taken from the sludge pond at the Hodrusa-Hamre model site. (authors)