[en] The half-life of ${}^{212}$Po was measured with the highest up-to-date accuracy as T${}_{1/2}$ = 295.1(4) ns by using thorium-loaded liquid scintillator.

[en] An attempt of changing the radioactive decay rate of atomic nuclei due to interference of wave functions of the initial nucleus and nuclei identical to radioactive decay products has been made. The first experiments have been performed with ²¹²Po undergoing α decay with a half-life of 0.3 μs. For ²¹²Po implanted into natural metallic lead, the increase in the decay rate by ∼0.2%, as compared to the decay rate of ²¹²Po in nickel, has been registered.

[en] The half-life of the ground state of ²¹²Po in the decay of ²¹²Bi has been measured by recording βα-delayed coincidences. The decay curve analyzed by the slope method gave the half-life T₁/₂(²¹²Po ground state) = 296 plus-or-minus 2 ns

[en] We have measured the reaction ²⁰⁸Pb(¹⁶O, ¹²C)²¹²Po at E₁₆O=93 MeV; the peak cross sections leading to the ground and first excited states of ²¹²Po are 750 and 1750 nb/sr, respectively. The reaction mechanism appears to be direct and excellent distorted-wave Born-approximation fits to the data yield a spectroscopic ratio of S (0.727 MeV, 2⁺)/S (g.s.) =0.64plus-or-minus0.13 in good agreement with the value 0.61plus-or-minus0.24 derived from ²¹²Po α decay. Preliminary attempts at obtaining absolute α widths yield γ/sub alpha/ ²(²¹²Po(g.s.)) approx.1.4 keV from both α decay and the transfer reaction

[en] We have studied the α-decays of ²¹⁴Po into ²¹⁰Pb and of ²¹²Po into ²⁰⁸Pb tagged by the coincidence with the preceding β-decays from ²¹⁴Bi and ²¹²Bi, respectively. The ²²²Rn, ²³²Th, and ²²⁰Rn sources used were sealed inside quartz vials and inserted in the Counting Test Facility at the underground Gran Sasso National Laboratory in Italy. We find that the mean lifetime of ²¹⁴Po is (236.00 ± 0.42(stat) ± 0.15(syst)) μs and that of ²¹²Po is (425.1 ± 0.9(stat) ± 1.2(syst)) ns. Our results, obtained from data with signal-to-background ratio larger than 1000, reduce the overall uncertainties and are compatible with previous measurements. (orig.)

[en] Polonium isotopes ²¹⁴Po and ²¹²Po are part of the ²³⁸U and ²³²Th decay chains, respectively. There exist only a few measurements of these two mean lifetimes with precision better than one or two percent. Since we have been studying decay spectra of ²¹⁴Bi and ²¹²Bi with the purpose of experimentally constraining anti-neutrino spectral shape important for geoneutrino studies, we have a large statistics of decays of ²¹⁴Po and ²¹²Po collected with the Counting Test Facility (CTF), which was operational in the underground I.N.F.N. Gran Sasso National Laboratory. The apparatus consisted of an external cylindrical water tank (diameter ∼ 11 m, high ∼ 10 m; ∼ 1000 tons of water) serving as passive shielding for 4.8 m³ of liquid organic scintillator contained in an inner spherical vessel with a diameter of ∼ 2 m. The inner vessel was realized with a nylon membrane (∼ 500 ?m thick), with excellent optical clarity, which allowed the effective transmission of the scintillation light to the 100 phototubes (PMTs) forming the optical read-out, anchored on a 7 m diameter support structure inside the water tank. The high purity and low background in CTF allows a favourable signal to background ratio for these measurements. More specifically the ratio of signal to background of the present measurements is more than three orders of magnitude larger than the best existing measurements. We have studied the decays of ²¹⁴Po into ²¹⁰Pb and of ²¹²Po into ²⁰⁸Pb tagged by the coincidence with the previously decays from ²¹⁴Bi and ²¹²Bi by using ²²²Rn, ²³²Th and ²²⁰Rn sources sealed inside quartz vials and inserted in the CTF

[en] Cluster-core potentials derived microscopically or phenomenologically each have some desirable features. We combine these features in an analysis of the properties of ²¹²Po treated as an α-²⁰⁸Pb system.

No abstract available

[en] Thoron (²²⁰Rn) and its progeny (²¹²Po) are primary contributors of inhalation dose to the public in HBRA. Similarly dose due to thoron is also significant in facility handling thorium enriched ores or materials. It becomes necessary to measure thoron exhalation rate (flux) in such region to estimate thoron source term. Also, the continuous measurement of thoron concentration levels in this region is helpful to determine the inhalation dose and to control the same. A reliable thoron monitor to carry out online thoron measurement is imperative for this purpose. The instruments currently available for online measurement of thoron are mainly based on electrostatic collection of freshly formed charged progenies of thoron. However, the humidity and trace gases present in the sample affects the collection efficiency of ²¹⁶Po, and hence interfere with the measurement of thoron. Thus measurement of thoron using the instruments based on electrostatic collection method in samples containing high humidity is unreliable due to interference from humidity. Usually a dryer device is connected in the sampling path to remove the humidity. This added volume of dryer device adds a time delay during which some fraction of thoron decays leading to reduction in sensitivity

No abstract available