[en] A decay scheme of ²¹⁴Pb has been developed on the basis of gamma-gamma coincidence and summing coincidence measurements. New levels are proposed at 62.69, 104.2 and 377.04 keV. The ground state, the 62.69 and the 102.4 levels of ²¹⁴Bi are fed in the alpha decay of ²¹⁸At. (orig.)

[en] The application of an α-γ coincidence method for measuring ²²⁶Ra concentrations in water is investigated. The experimental system, sample preparation, and results of several measurements are discussed. In addition, the lower limit of detection for the coincidence system is calculated. The present work indicates that the α-γ coincidence technique is a viable alternative to traditional methods of ²²⁶Ra analysis. (author)

[en] This chapter shows the decay series which produce astatine isotopes, the half-lives and global inventory of them. (PW)

[en] The decay of Po 218 is accompanied by the emission of 6.00-MeV alpha particles. The most suitable method for studying it is the alphaspectrometric method. To generate radon, the source for RaA, the authors used a preparation of Ra 226 with a high degree of purity. Targets were prepared for measuring the half-life on a radon setup. Approximately 30 sec after holding in a radon atmosphere the target was placed with the polonium deposited on it into a vacuum chamber. It was noted that the intensity of the peak at 6.70 MeV decreases at the same rate as the decay of Po 218, and the ratio of the intensities of their peaks was equal to 0.037 +/- 0.007%. The spectra (alpha was analyzed on an LP-4900 analyzer. The values of the half-life that were obtained are in good agreement with the values obtained previously

[en] This evaluation was completed in 2007. Literature available by January 2007 was included. Decay Scheme; ²¹⁸At disintegrates by alpha emission (99.9 (1)%) to ²¹⁴Bi mainly. The γ transitions between the ²¹⁴Bi levels have not been observed. However, a Q value of 6811 (12) keV is calculated in the disintegration of ²¹⁸At to ²¹⁴Bi from the decay scheme data compared to a value of 6867 (3) keV from the Audi's tables. This deficiency in the calculated Q value suggests the possible existence of a weak gamma transition from the 62-keV to the ground state levels. A weak beta minus emission (0.1 (1)%) to Rn-218 has been pointed out (1948Wa20). Spins and parities are from the mass-chain evaluation of Y. A. Akovali (1987El12, 1995El08 for A = 218 and 1995El07 for A = 214) and A. K. Jain (2006Ja03 for A = 218)

[en] This evaluation was completed in 2007. Literature available by January 2007 was included. The half-life value was re-evaluated in Dec. 2010 in order to include the Martz's result. Decay Scheme; ²¹⁸Po disintegrates by alpha emission mainly (99.978 (3)%) to the ground state level of ²¹⁴Pb. A weak beta minus emission (0.022 (3)%) to At-218 has been pointed out. Spin and parity are from the mass-chain evaluation of Y. A. Akovali (1987El12, 1995El08, 1998Ak04 for A = 218 and 1995El07 for A = 214) and A. K. Jain (2006Ja03 for A = 218). A good agreement was found between the recommended Q value of Audi and the effective Q value of 6113.33 (22) keV for the α branch, calculated from the decay scheme data

[en] A 220 GHz unbalanced tripler based on Schottky varactors was designed. The Schottky varactors were measured to extract parameters for modeling Schottky diodes. A lump equivalent circuit model of Schottky diode was established for 220 GHz tripler circuits design. To reduce the signal transmission loss, a compact suspended microstrip resonator cell (CSMRC) filter structure was introduced to reduce low pass filter circuit length. Since it was difficult to achieve full-wave impedance matching in 220 GHz tripler circuit design, we adopted a method of adjusting impedance matching in overall circuit structure harmonic balance simulation to design a 220 GHz tripler circuit. Finally, the designed 220 GHz tripler was measured and discussed. The experiment shows the output power and efficiency between 213.1 GHz and 221.6 GHz are above 10 mW and 5%, respectively. The maximum output power is 18.7 mW at 218.6 , GHz and the maximum efficiency is 8.2% at 217.9 GHz. (authors)

[en] Nuclear structure information for all nuclei with mass number A=218 is evaluated. The results from various decay experiments are compared. Adopted data, levels, and spin and parity assignments are given

[en] An apparatus is described and a method presented for the determination of concentrations of radon emanated from solid and liquid samples. In this method an object under consideration or a sample of air is enclosed in an hermitically sealed chamber. The air contaminated by radon and its daughters is circulated in a closed system a few times through an electrostatic precipitator mounted in the same housing as a semiconductor Si(Li) detector. The concentration of radon is determined by measuring the alpha activity of its daughters. With the application of an electrostatic precipitator and a silicon detector it is possible to perform alpha spectrometric measurements and thus separate activities of RaA, RaC', and ThC, and to calculate ²²²Rn of ²²⁰Rn concentrations. The efficiency of RaA, RaB, RaC, ThB, ThC collection is constant, because the method involves the circulation of the air through the electrostatic precipitator several times. The sensitivity of the apparatus is high. The minimum detectable radon concentration calculated from an activity measurement of RaA (fast method) is about 0.46 pCi/l and when measuring the activity of RaC', (slow method) it is 0.028 pCi/l. (orig.)

[en] A comparison of the Q_eff calculated from the proposed decay scheme and the value taken from the Atomic Mass Evaluation 2003 was presented for the fifteen radionuclides evaluated at LNHB. The evaluation of one remaining radionuclide is still ongoing (²⁴³Am). The comparison showed satisfactory agreement within the data uncertainties for all but two cases: calculated Q-value is ∼1% lower than the value adopted for ²¹⁸At, suggesting the possible existence of a weak gamma transition from the 62-keV level to the ground state of daughter ²¹⁴Bi; calculated Q-value for ²¹⁰Tl has a very large data uncertainty (∼18%) owing to the lack of knowledge of the decay scheme. The intensities of the K and L X-rays, as determined from the decay scheme, were compared with measured values, if available, for seven radionuclides. Overall agreement was found, with the particular exception of ²¹⁴Bi for which a major disagreement exists, but this may arise from the complexity of the measured X-ray spectrum making resolution and deconvolution difficult. The status of available experimental data for the fifteen radionuclides already evaluated was presented, and requirements for future measurements were listed. No direct measurements of transition probabilities exist in a number of cases, and only one or two half-life studies have been published for specific nuclides, making their evaluation extremely susceptible to the uncertainties in these values. The LNHB publish evaluations carried out within the Decay Data Evaluation Project (DDEP) in the form of a Monographie of the Bureau International des Poids et Mesures (BIPM), Sevres, France. Volume 4 of Monographie BIPM-5 will appear at the end of 2008, and should contain details of thirty-two evaluations, twenty-seven of which are associated with the CRP, while volume 5 should be published in 2009, which will also predominantly contain decay data evaluations produced by the CRP