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Isolated limb perfusion (ILP) is a method for treating unresectable lesions of limbs in patients with melanoma or sarcoma by using high doses of tumor necrosis factor alpha and melphalan. This high doses can result in high systemic toxicity if there is a drug leak from the isolated circulation of the limb to the systemic. This makes it imperative to monitor the leakage rate (F(%)) during the infusion, currently performed with radiotracers. The objective of this work was to develop a leakage monitoring protocol as accurate as possible to ensure safe ILP. Material and method We built a phantom with three compartments (body, limb and precordial area) and a high sensitivity collimator fitted to a portable gamma camera. We simulate ILP with scheduled leaks every 10 min from 1% to 9% (theorical F(%)). We mesured F(%) using two equation: one is the proposed in the literature and another corrected by decay of the radioisotope. We test the optimal radiopharmaceutical doses to minimize the detector dead time error and compare F(%) mesured by both equations regarding the theoretical F(%). The leakage monitoring protocol was used in 17 ILP of 16 patients and an analysis of the recorded data was performed. Results We found significant differences between F(%) mesured using the first equation and theoretical F(%), obtaining results very adjusted to the theorical after applying the decay correction. Conclusions the decay correction of the radioisotope is a simple manner to carry out the procedure more safely, reducing the error in the calculation of F(%).

Ground-based gamma-ray spectrometry using a LaBr3(Ce) detector was conducted to assess radioactive cesium deposition in soil contaminated by the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in Japan. Five sites, including a reference site with relatively low contamination, were selected as having different levels of ambient dose rate due to significant effects of radioactive fallout of 134Cs and 137Cs. According to ICRU Report 53, the radioactivity in the ground and dose rate at 1 m above the ground were determined from the measured net count rates of gamma-rays induced from radioactive cesium. Because the radioactivity and dose rate depended on the depth profile of radioactive cesium in the ground, a database of possible radioactivity and dose rate could be established according to several depth distributions. A new approach to estimate the depth profile was then developed by directly calculating dose rates of 134Cs and 137Cs at the same geometry through dose rate spectroscopy and comparing them with the database of possible dose rates of radioactive cesium. Once the depth profile was determined, radioactivity was estimated from the database depending on the depth profile in the ground. The activity ratio between two radioactive cesium was shown to average about 0.112, in December 2017. It was in good agreement with the originally same released amount of 134Cs and 137Cs at the time of the FDNPP accident, when physical decay correction was applied to the results of the radioactivity assessment.

Accurate analysis of N fixation in leguminous crops requires determination of N utilization within an intact plant; however, most approaches require tissue disassembly. We developed a simple and rapid technique to generate high-purity and high-yield [13N]N2 gas and obtained real-time images of N fixation in an intact soybean plant. The purification efficiency was ∼81.6% after decay correction. Our method provides accurate signals of N fixation and allows free changes to the tracer gas composition to suit different experimental designs.

Quantitative myocardial PET perfusion requires decay correction of the dynamic datasets to ensure measured activity reflects true physiology and not radiotracer decay or duration of frame intervals. Decay correction is typically performed by the PET camera system and the exact algorithm is buried within the settings and assumed to be correct for quantitative perfusion data. For quantitative myocardial perfusion, sequential dynamic images should be decay corrected to the activity at the mid time point of the first scan in the sequence. However, there are different decay correction algorithms that can be implemented depending on the needs and expertise of the laboratory. As such, prior to performing quantitative myocardial perfusion, testing the decay correction technique of a camera system should be performed.

Albergo thermometers with double isotope, isotone, and isobar yield ratio pairs with one proton and/or neutron difference are investigated. Without any extra sequential decay correction, a real temperature value of $4.9\ifmmode\pm\else\textpm\fi{}0.5$ MeV is deduced from the yields of the experimentally reconstructed primary hot intermediate mass fragments (IMFs) from $^{64}\mathrm{Zn}+^{112}\mathrm{Sn}$ collisions at 40 MeV/nucleon using the Albergo thermometer for the first time. An experimental sequential decay correction from the apparent temperatures to the real ones for 12 other reaction systems with different neutron-proton ($N/Z$) asymmetries in the same experiment, $^{70}\mathrm{Zn}$, $^{64}\mathrm{Ni}$ on $^{112,124}\mathrm{Sn}$, $^{58,64}\mathrm{Ni}$, $^{197}\mathrm{Au}$, and $^{232}\mathrm{Th}$ at 40 MeV/nucleon, is performed using an empirical correction factor approach of Tsang et al. [Phys. Rev. Lett. 78, 3836 (1997)] with the deduced 4.9-MeV temperature value. The dependence of nuclear temperature on the source $N/Z$ asymmetry is further investigated using these deduced real source temperature values from the present 13 systems. It is found that the deduced real source temperatures at the present source $N/Z$ range show a rather weak dependence on the source $N/Z$ asymmetry. By comparison between our previous results and those from other independent experiments, a consistent description for the $N/Z$ asymmetry dependence of nuclear temperature is addressed.

The determination of 90Sr by ICP-MS is capable of providing a high sample throughput compared with radiometric analytical methods. Although the isobaric interference caused by 90Zr ions can be reduced by reaction with oxygen, the high background caused by stable 88Sr has made it difficult to determine 90Sr by conventional ICP-MS. In this study, a rapid and sensitive method was developed for the determination of 90Sr using triple quadrupole ICP-MS. The MS/MS configuration improves the abundance sensitivity by more than two orders of magnitude (5 × 10−12), and the detection limit for 90Sr in 1 g environmental samples was 0.6 Bq kg−1. The applicability of the method to the measurement of 90Sr in environmental samples was demonstrated by analysis of certified reference materials (soil: IAEA 375; plant: IAEA 330, IAEA 373) contaminated by the Chernobyl accident. The measured 90Sr radioactivities in the samples were consistent with values determined by radiometric analysis, within analytical error. The measured 90Sr concentration in IAEA 372 was 610 ± 40 Bq kg−1 (SD, n = 3) (Decay correction was made to December 1, 2016). This method provides a powerful tool for the investigation of radiostrontium contaminations in the Fukushima area and elsewhere.

We present a method of analysis of nuclear decay spectra affected by extending dead-time, in which a non-trivial, but relatively simple correction for dead-time losses is applied to produce an estimate of the spectrum in the absence of dead-time, with negligible bias and negligible deviation from the original Poissonian statistics. The method requires the measurement of arrival times of all observed decay events, but it does not require any knowledge about the dead-time or the nuclear decay. The parameters of nuclear decay can be determined in a subsequent straight-forward analysis of the estimated dead-time free spectra, individually or in combinations. In a typical realistic situation this approach is expected to contribute 0.001% or less to the systematic error of nuclear half-life or activity. Compared to the exact method of analysis presented in our earlier publication, the present method is much easier to implement and produces the results significantly faster.

The acquisition of time-stamped list data provides additional information useful to gamma-spectrometry analysis. A novel technique is described that uses non-linear least-squares fitting and the Levenberg–Marquardt algorithm to simultaneously determine parent-daughter atoms from time sequence measurements of only the daughter radionuclide. This has been demonstrated for the radioactive decay of short-lived radon progeny (214Pb/214Bi, 212Pb/212Bi) described using the Bateman first-order differential equation. The calculated atoms are in excellent agreement with measured atoms, with a difference of 1.3–4.8% for parent atoms and 2.4–10.4% for daughter atoms. Measurements are also reported with reduced uncertainty. The technique has potential to redefine gamma-spectrometry analysis.

Decay heat and delayed neutron yields, which are important physical quantities in the field of the nuclear engineering, are dependent on common nuclear data such as radioactive decay data and fission yields data of fission product nuclides. In the present study, correlations between uncertainties of these two quantities are investigated. Nuclear data relevant to uranium-235 and plutonium-239 fissions with thermal neutron are adjusted consistently with a procedure based on Bayes’ theorem using the measurement data of decay heat and delayed neutron activities. Numerical results suggest that the correlation between decay heat and delayed neutron activities uncertainties is not significant, and that independent treatments of decay heat or delayed neutron activities are possible. The effect of the consistent treatment of decay heat and delayed neutron activities is, however, observed in the adjustment results in some nuclear data such as uranium-235 thermal fission yields of yttrium-100m and zirconium-100.

A method for estimating source strength measurements of californium neutron sources is presented, based on the model of 252Cf, 250Cf, and 248Cm decay. This is combined with the Monte Carlo method (MCM) of propagating uncertainties. Californium sources were categorized into two types: Sort–A are those with most input quantities known while Sort–B are sources with only the mass at a certain reference date known. For Sort–A, the spread of all input quantities was estimated with Gaussian distribution and the deterministic 1st order GUM uncertainty propagation is applied to validate the MCM results. While, for Sort–B with inputs that have non-Gaussian distributions, only MCM is applied to evaluate uncertainties. Results show that for californium sources that are 25 y or older, a simple 252Cf decay correction is imprecise due to the contribution of 250Cf and 248Cm. The MCM was also shown to be a robust technique for uncertainty analysis that provides results for both Gaussian and non-Gaussian distributions. Moreover, the time-dependence of the contributors in the source strength and the corresponding uncertainties are presented. When exceedingly low uncertainties are not required, the calculation techniques presented in this work may serve as an alternative to actual measurements, which tend to be expensive.

The main advantage of the 40Ar/39Ar method over conventional K–Ar dating is that it does not depend on any absolute abundance or concentration measurements, but only uses the relative ratios between five isotopes of the same element –argon– which can be measured with great precision on a noble gas mass spectrometer. The relative abundances of the argon isotopes are subject to a constant sum constraint, which imposes a covariant structure on the data: the relative amount of any of the five isotopes can always be obtained from that of the other four. Thus, the 40Ar/39Ar method is a classic example of a ‘compositional data problem’. In addition to the constant sum constraint, covariances are introduced by a host of other processes, including data acquisition, blank correction, detector calibration, mass fractionation, decay correction, interference correction, atmospheric argon correction, interpolation of the irradiation parameter, and age calculation. The myriad of correlated errors arising during the data reduction are best handled by casting the 40Ar/39Ar data reduction protocol in a matrix form. The completely revised workflow presented in this paper is implemented in a new software platform, Ar-Ar _ Redux , which takes raw mass spectrometer data as input and generates accurate 40Ar/39Ar ages and their (co-)variances as output. Ar-Ar _ Redux accounts for all sources of analytical uncertainty, including those associated with decay constants and the air ratio. Knowing the covariance matrix of the ages removes the need to consider ‘internal’ and ‘external’ uncertainties separately when calculating (weighted) mean ages. Ar-Ar _ Redux is built on the same principles as its sibling program in the U–Pb community ( U-Pb _ Redux ), thus improving the intercomparability of the two methods with tangible benefits to the accuracy of the geologic time scale. The program can be downloaded free of charge from http://redux.london-geochron.com .

Purpose: Understanding the distribution and interaction of the traditional Chinese medicines (TCMs) is an integral facet of herbal drug discovery. We report an optimized radio-labelled method that could conduct biodistribution studies in situ at the animal level in vivo. Viability of the method has been evaluated analytically and applied using glycyrrhetic acid (GA) and Platycodon grandifloras (PG) polysaccharides as a model. Procedures: [18F]-GA is a novel radiotracer which was performed whole-body positron emission tomography (PET) studies in mice to evaluate the biodistribution and dosimetry of GA. In addition, PG polysaccharides was used to intervene the biodistribution and dosimetry of GA. Data were analyzed using PMOD and Matlab software. Results: All organ time-activity curves without decay correction were normalized to the injected activity. The area under the normalized curves was then used to compute the dosimetry in each organ. The absorbed doses in mouse organs were computed using the Radiation Dose Assessment Resource animal models for dose assessment. Moreover, the addition of PG polysaccharides can significantly improve the dosimetry of GA in the lungs, and its effect was related to the administration time. Conclusions: Whole-body mouse imaging opens up a new avenue for the application of drug interactions between the TCMs.

The decay characteristics of 61 Cu allow for a precise determination of its half-life. In order to search for a possible influence of the chemical environment on the decay rate, the half-life of 61 Cu in nickel and nickel-oxide was measured with high precision. The results show a small difference in the half-life that can be explained by the differences in electron density at the site of the nucleus. A discussion about the validity of the adopted value of the total angular momentum of the 656 keV state in 61 Ni is presented.

The decay properties of various even–even isotopes of barium in the range 112 ≤A ≤ 122 is studied by modifying the Coulomb and proximity potential model for both the ground and excited state decays, using recent mass tables. Most of the values predicted for ground state decays are within the experimental limit for measurements (T 1/2 < 1030 s). The minimum T 1/2 value refers to doubly magic or nearly doubly magic Sn (Z= 50) as the daughter nuclei. A comparison of log 10(T 1/2) value reveals that the exotic cluster decay process slows down due to the presence of excess neutrons in the parent nuclei. The half-lives are also computed using the Universal formula for cluster decay (UNIV) of Poenaru et al and the Universal decay law (UDL) of Qi et al, and are compared with CPPM values and found to be in good agreement. A comparison of half-life for ground and excited systems reveals that probability of decay increases with a rise in temperature or otherwise, inclusion of excitation energy decreases the T 1/2 values.

A custom-built liquid scintillation counter was used for long-term measurements of 90 Sr / 90 Y sources. The detector system is equipped with an automated sample changer and three photomultiplier tubes, which makes the application of the triple-to-double coincidence ratio (TDCR) method possible. After decay correction, the measured decay rates were found to be stable and no annual oscillation could be observed. Thus, the findings of this work are in strong contradiction to those of Parkhomov (2011) who reported on annual oscillations when measuring 90 Sr / 90 Y with a Geiger–Muller counter. Sturrock et al. (2012) carried out a more detailed analysis of the experimental data from Parkhomov and claimed to have found correlations between the decay rates and processes inside the Sun. These findings are questionable, since they are based on inappropriate experimental data as is demonstrated in this work. A frequency analysis of our activity data does not show any significant periodicity.

243 Objectives The objectives of this study was to identify prevalence of respiratory motion in dynamic PET myocardial perfusion images, its effects on myocardial blood flow (MBF) and coronary flow reserve (CFR) estimates and to investigate the implications of the weighting model deployed during kinetic fit to minimize effects of motion. Methods This study used 53 randomly selected patients referred for dynamic stress/rest Rb-82 PET imaging. Dynamic image series were iteratively reconstructed. The left ventricular (LV) blood pool and tissue time activity curves (TAC) were sampled using ROI and fit to a compartment model with uniform or tissue weighting for MBF and CFR quantification using Corridor4DM software (INVIA). Tissue weighting incorporated the frame duration, decay correction factor, and activity concentration. Motion was assessed visually from the dynamic series and categorized with having minimal, moderate, or severe motion. Studies with moderate or severe motion were manually corrected for comparison. Results Moderate and severe motion was observed in 46% and 39% of the studies respectively. Motion was most prominent in the blood pool phases with 55% of the motion in the craniocaudal direction. Compared to the motion corrected images, images with moderate motion had global stress MBF values 3.2% higher when uniform weighting was used. Using tissue weighting only reduced those differences by 0.5%. Studies with severe motion had greater stress MBF differences: 5.8% (uniform) and 5.4% (tissue). Regionally stress MBF values in the RCA varied the greatest: 20.2% (uniform) and 19.9% (tissue). Conclusions Respiratory motion is problematic in the blood pool phase due to fast kinetics of the tracer and the short time sampling. Increasing differences in MBF and CFR estimates were observed between studies with minimal, moderate, and severe motion. Tissue weighting has limited impact on reducing the increase in MBF and CFR estimates caused by motion suggesting motion correction is needed to reduce bias in flow estimates.

It is a long-held tenet of nuclear physics, from the early work of Rutherford and Soddy up to present times that the disintegration of each species of radioactive nuclide occurs randomly at a constant rate unaffected by interactions with the external environment. During the past 15 years or so, reports have been published of some 10 or more unstable nuclides with non-exponential, periodic decay rates claimed to be of geophysical, astrophysical, or cosmological origin. Deviations from standard exponential decay are weak, and the claims are controversial. This paper examines the effects of a periodic decay rate on the statistical distributions of 1) nuclear activity measurements and 2) nuclear lifetime measurements. It is demonstrated that the modifications to these distributions are approximately 100 times more sensitive to non-standard radioactive decay than measurements of the decay curve, power spectrum, or autocorrelation function for corresponding system parameters.

The general radioactive decay kinetics equations with branching were developed and the analytical solutions were derived by Laplace transform method. The time dependence of all the nuclide concentrations can be easily obtained by applying the equations to any known radioactive decay series. Taking the example of thorium radioactive decay series, the concentration evolution over time of various nuclide members in the family has been given by the quantitative numerical calculations with a computer. The method can be applied to the quantitative prediction and analysis for the daughter nuclides in the successive decay with branching of the complicated radioactive processes, such as the natural radioactive decay series, nuclear reactor, nuclear waste disposal, nuclear spallation, synthesis and identification of superheavy nuclides, radioactive ion beam physics and chemistry, etc.

The use of the tools of formal chemical kinetics for calculating the total α-, β-, and γ-ray spectra in decay of radioactive isotopes is suggested. Principles of constructing a reaction scheme modeling the radioactive decay of the initial isotope and chain of its daughter nuclides are described. The reaction scheme allows calculation of the total current radiation spectra, total decay energy, and gas (He) formation along with variation of the isotope composition.

Tests for chemical stability were carried out on carrier-added (68)Ge solutions prepared and calibrated in 2007 and 2011 to evaluate the suitability of the specific composition as a potential Standard Reference Material. Massic count rates of the stored solutions were measured using a NaI(Tl) well counter before and after gravimetric transfers. The present activity concentration of the 2007 solution was also measured using live-timed anticoincidence counting (LTAC) and compared to the 2007 calibrated value. The well counter data indicated no change in massic count rate to within uncertainties for either solution. The LTAC measurements gave a difference of -0.49% in the activity concentration 2007 solution over 7 years. However, the uncertainty in the decay correction over that time, due to the uncertainty in the (68)Ge half-life, accounted for the majority (0.67% out of 0.83%) of the standard uncertainty on the activity concentration. The results indicate that these carrier-added solutions are stable with regard to potential activity losses over several half-lives of (68)Ge.

International audience; The Fortran subroutine package PENNUC, which simulates random decay pathways of radioactive nuclides, is described. The decay scheme of the active nuclide is obtained from the NUCLEIDE database, whose web application has been complemented with the option of exporting nuclear decay data (possible nuclear transitions, branching ratios, type and energy of emitted particles) in a format that is readable by the simulation subroutines. In the case of beta emitters, the initial energy of the electron or positron is sampled from the theoretical Fermi spectrum. De-excitation of the atomic electron cloud following electron capture and internal conversion is described using transition probabilities from the LLNL Evaluated Atomic Data Library and empirical or calculated energies of released X rays and Auger electrons. The time evolution of radiation showers is determined by considering the lifetimes of nuclear and atomic levels, as well as radiation propagation times. Although PENNUC is designed to operate independently, here it is used, in conjunction with the electron-photon transport code PENELOPE, and both together allow the simulation of experiments with radioactive sources in complex material structures consisting of homogeneous bodies limited by quadric surfaces. The reliability of these simulation tools is demonstrated through comparisons of simulated and measured energy spectra from radionuclides with complex multi-gamma spectra, nuclides with metastable levels in their decay pathways, nuclides with two daughters, and beta plus emitters.

The NEMO-3 experiment measured the half-life of the 2νββ decay and searched for the 0νββ decay of 116Cd. Using 410 g of 116Cd installed in the detector with an exposure of 5.26 y, (4968±74) events corresponding to the 2νββ decay of 116Cd to the ground state of 116Sn have been observed with a signal to background ratio of about 12. The half-life of the 2νββ decay has been measured to be T2ν1/2=[2.74±0.04(stat.)±0.18(syst.)]×1019 y. No events have been observed above the expected background while searching for 0νββ decay. The corresponding limit on the half-life is determined to be T0ν1/2≥1.0×1023 y at the 90 % C.L. which corresponds to an upper limit on the effective Majorana neutrino mass of ⟨mν⟩≤1.4−2.5 eV depending on the nuclear matrix elements considered. Limits on other mechanisms generating 0νββ decay such as the exchange of R-parity violating supersymmetric particles, right-handed currents and majoron emission are also obtained.

Motivated by the need for consistent use of concepts central to the reporting of results from measurements of atmospheric radioactivity, we discuss some properties of the methods commonly used. Different expressions for decay correction of the activity concentration for parent-daughter decay pairs are presented, and it is suggested that this correction should be performed assuming parent-daughter ingrowth in the sample during the entire measurement process. We note that, as has already been suggested by others, activities rather than activity concentrations should be used when nuclide ratios are calculated. In addition, expressions that can be used to transform activity concentrations to activity ratios are presented. Finally we note that statistical uncertainties for nuclide ratios can be properly calculated using the exact solution to the problem of confidence intervals for a ratio of two jointly normally distributed variables, the so-called Fieller׳s theorem.

International audience; Within the Decay Data Evaluation Project, as an example of a radioactive equilibrium with isomer, the 99Mo/99m Tc equilibrium mixture decay characteristics are examined. The results of a new decay data evaluation are presented for 99Mo/99mTc decay to nuclear levels in 99Tc. These evaluated data have been obtained using information published up to 2013.

Purpose Important advancements have been made in PET image reconstruction algorithms, among the newest point spread function (PSF) and noise statistics modelling (NSM) can be accounted for. This work presents the preliminary results of the application of these reconstruction techniques on 3 state-of-the-art PET/CT scanners with and without time-of-flight (TOF) technique. Methods A Ge68 NEMA/IEC phantom (Data Spectrum, Durham, NC) filled with 68Ge in an epoxy resin was used. The activity concentrations in the spheres and in the background were measured with a radionuclide calibrator tested against a NIST traceable source and were respectively 40.67 kBq/ml and 10.58 kBq/ml at reference time (uncertainty ± 3)%. Nominal sphere-to-background ratio was 3.84. Total activity in the phantom was 108.4 MBq. The phantom was acquired for a prolonged time according to decay correction equivalent to 1.5 min per frame at the reference date on each PET scanner and reconstructed with clinical reconstruction parameters with traditional (OSEM) and by combining advanced modalities, when present: PSF, TOF, TOF + PSF, NSM. For each PET scanner and each reconstruction modality the maximum Recovery Coefficient (RCmax) values were evaluated for each visible sphere. RCmax were normalised to background activity to cancel calibration bias among scanners. Results The Figure presents the RCmax averaged on the 3 PET/CT scanners together with the RC limits suggested by EARL. Error bars represent one standard deviation. Conclusions the RC obtained with the 3 state-of-the-art non digital PET/CT scanners demonstrate clearly that, independently of the reconstruction method used, modern PET/CT scanner outperforms respect to older one described by EARL curve. Moreover, applying more advanced reconstruction techniques progressively enhances RC, NSM reconstruction being the most promising setup. Even if RCmax of different scanners converge at larger (>22 mm) and smaller (10 mm) spheres, the overestimations observed in the size between 1 and 2 cm are currently under investigation.

Evaluations of the characteristics of the radionuclides 242Cm, 243Cm, 244Cm, and 245Cm obtained from data published up to 2013 are presented. A computer program is developed for constructing and visualizing the decay schemes of radionuclides and is used to determine the decay schemes for these curium isotopes.

The distribution of radon in ground and surface water samples in Sankey Tank and Mallathahalli Lake areas was determined using Durridge RAD-7 analyzer with RAD H2O accessory. The radiation dose received by an individual falling under different age groups (viz., 3 months; 1, 5, 10, 15 years and adult) depending upon their average annual water consumption rate was attempted. The mean radon activity in surface water of Sankey Tank and Mallathahalli Lake was 7.24 ± 1.48 and 11.43 ± 1.11 Bq/L, respectively. The average radon activities ranged from 11.6 ± 1.7 to 381.2 ± 2.0 Bq/L and 1.50 ± 0.83 to 18.9 ± 1.59 Bq/L, respectively, in 12 groundwater samples each around Sankey Tank and Mallathahalli Lake areas. Majority of the measured groundwater samples (viz., 100 % in Sankey Tank area and 75 % in Mallathahalli Lake area) showed mean radon values above the EPA’s maximum contaminant level of 11.1 Bq/L and only 66.67 % of samples in Sankey Tank area showed radon above the WHO and EU’s reference level of 100 Bq/L. The overall radiation dose due to radon emanating from water in the study area was increasing with increase in age and water consumption rates, but significantly lower than UNSCEAR and WHO recommended limit of 1 mSv/year except for few groundwater samples in Sankey Tank area (i.e., 0.92, 0.99 and 1.39 mSv/year). The radiation dose rate received by bronchial epithelium via inhalation was very high compared to that by stomach walls via ingestion.

The isotopic ratios of radioactive cesium derived from the Fukushima accident were determined by γ-spectrometry and thermal ionization mass spectrometry (TIMS). In order to ascertain the initial ratios at the time of the accident, environmental samples collected during 2011 were used for the analysis. Soil, litter, and seaweed were incinerated, and the cesium contained therein was adsorbed into ammonium phosphomolybdate powder. The cesium in the seawater was adsorbed into AMP-PAN resin (Eichrom Technologies, LLC); its recovery ratio was almost one without the carrier being added. Incinerated samples and the AMP-PAN resin were then measured by γ-spectrometry. The cesium solution recovered from adsorbers was subjected to TIMS measurements. The isotopic ratios of 134Cs/137Cs and 135Cs/137Cs were found to be independent of the type of sample in question, as well as the sampling location; the ratios were 0.07 and 0.36 (decay correction: 11 March 2011), respectively, which differ from the results of atmospheric nuclear tests (i.e., 0 and 2.7, respectively). This difference in the ratio of 135Cs/137Cs will contribute to estimations of the origin of radioactive contamination in the future.

The radionuclide 125 Sb is a long-lived fission product, which decays to 125 Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125 Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125 Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125 Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144 keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented.

Plutonium (Pu) dioxide particles were produced from certified reference material (CRM) 136 solution (CRM 136-plutonium isotopic standard, New Brunswick Laboratory, Argonne, IL, U.S.A., 1987) using an atomizer system on December 3, 2009 after chemical separation of americium (Am) on October 27, 2009. The highest density of the size distribution of the particles obtained from 312 particles on a selected impactor stage was in the range of 0.7-0.8 μm. The flattening degree of 312 particles was also estimated. The isotopic composition of Pu and uranium (U) and the amount of Am were estimated by thermal ionization mass spectrometry (TIMS), inductively coupled plasma mass spectrometry (ICPMS), and α-spectrometry. Within uncertainties the isotopic composition of the produced particles is in agreement with the expected values, which were derived from the decay correction of the Pu isotopes in the CRM 136. The elemental ratio of Am to Pu in the produced particles was determined on the 317th and 674th day after Am separation, and the residual amount of Am in the solution was estimated. The analytical results of single particles by micro-Raman-scanning electron microscopy (SEM)-energy-dispersive X-ray spectrometry (EDX) indicate that the produced particles are Pu dioxide. Our initial attempts to measure the density of two single particles gave results with a spread value accompanied by a large uncertainty.

Decay of neutron-deficient 128 − 137Gd parents emitting 4He to 32S clusters are studied within the Coulomb and proximity potential model. The predicted half-lives are compared with other models and most of the values are well within the present experimental limit for measurements (T1/2 < 1030 s). The lowest T1/2 value for 28Si emission from 128Gd indicates the role of doubly magic 100Sn daughter in cluster decay process. It is also found that neutron excess in the parent nuclei slows down the cluster decay process. Geiger–Nuttal plots for all clusters are found to be linear with different slopes and intercepts. The α-decay half-lives of 148 − 152Gd parents are computed and are in agreement with experimental data. The role of doubly magic 132Sn daughter in cluster decay process is also examined for various neutron-rich Ba, Ce, Nd, Sm and Gd parents emitting clusters ranging from 4He to 32Si. Alpha-like structures are most probable in the decays leading to 100Sn, while non-α-like structures are probable in the decays leading to 132Sn. The neutron–proton asymmetry in parent and daughter nuclei is responsible for the reduced decay rate in the decay leading to 132Sn.

High-precision measurements were conducted on the time evolution of gamma-ray count rates during reactor-on and reactor-off periods to investigate the possible influence of antineutrinos on nuclear decay. This experiment was triggered by a recent analysis (Jenkins et al., 2009) of long-term measurements suggesting a possible link to variations in nuclear decay rate and solar neutrino flux. The antineutrino flux during reactor-off periods is mainly due to geoneutrinos and four orders of magnitude lower than during reactor-on periods. No effects have been observed for the two branches in the decay of (152)Eu and the decay of (137)Cs, (54)Mn and (22)Na. The upper limit determined of the ratio Δλ/λ for (22)Na is (-1±2)×10(-4), and (54)Mn is (-1±4)×10(-4). In comparison to the interpretation of Jenkins et al. our measurements do not show any such effect to at least two orders of magnitude less. Hence either the hypothesis of Jenkins et al. is not true or else one of two rather unlikely possibilities must also be true: either the effect of neutrinos on β(-) decay differs considerably from the effect of antineutrinos on β(+) decay, or the effect of antineutrinos on β(+) decay must be identical to their effect on β(-) and electron-capture decay.

109 Cd decays to the excited states of 109 Ag through the electron capture decay mode. The evaluation of the complete decay scheme and data of 109 Cd including the recent new measurements is presented in this report. The limitation of relative statistical weight method (LRSW) was applied to average numbers throughout the evaluation. The uncertainty assigned to the average value was always greater than or equal to the smallest uncertainty of the values used to calculate the average. The half-life is determined to be 462.0±0.3 days. All known measured absolute emission probabilities for gamma-ray and KX-ray have been examined. And the gamma-ray emission probability of the reference γ line of 88.0336 keV is recommended to be 3.65±0.3%. The internal conversion coefficients and their uncertainties were used to obtain the complete decay intensity balance. The other decay characteristics are calculated using the ENSDF analysis program. Finally the 109 Cd decay scheme was given.

We report an algorithm for real-time control of the fuel of a DMFC. The MEA voltage decay coefficients [ e 1 , e 2 ], and I – V – T , M ′– I – T , and W ′– I – T curves (where I is the current, V the voltage, T the temperature, and M ′ and W ′ the methanol and water consumption rates, respectively) of n fuels with specified methanol concentrations C M , k ( k = 1, 2,…, n ) are pre-established and form ( I , V , T ), ( M ′, I , T ), and ( W ′, I , T ) surfaces for each C M , k . The in situ measured ( I , V , T ) u after voltage decay correction is applied to the n preset ( I , V , T ) surfaces to estimate C M , u (the C M corresponding to ( I , V , T ) u ) using an interpolation procedure. The C M , u is then applied to the n preset ( M ′, I , T ) and ( W ′, I , T ) surfaces to estimate cumulated “methanol” and “water” consumed quantities . Thus in a real-time system, the C M and total quantity of fuel can be controlled using the estimated C M , u and cumulated “methanol” and “water” consumed quantities.

1-H-1-(3-[18F]fluoro-2-hydroxypropyl)-2-nitroimidazole ([18F]FMISO), is the most used hypoxia-imaging agent in oncology and we have recently reported a fully automated procedure for its synthesis using the Nuclear Interface FDG module and a single neutral alumina column for purification. Using 1-(2′-nitro-1′-imidazolyl)-2-O-tetra-hydropyranyl-3-O-toluenesulfonylpropanediol (NITTP) as the precursor, we have investigated the yield of [18F]FMISO using different reaction times, temperatures, and the amount of precursor. The overall yield was 48.4 ± 1.2% (n = 3), (without decay correction) obtained using 10 mg NITTP with the radio-fluorination carried out at 145 °C for 3 min followed by acid hydrolysis for 3 min at 125 °C in a total synthesis time of 32 ± 1 min. Increasing the precursor amount to 25 mg did not improve the overall yield under identical reaction conditions, with the decay uncorrected yield being 46.8 ± 1.6% (n = 3), but rather made the production less economical. It was also observed that the yield increased linearly with the amount of NITTP used, from 2.5 to 10 mg and plateaued from 10 to 25 mg. Radio-fluorination efficiency at four different conditions was also compared. It was also observed by radio thin layer chromatography (radio-TLC) that the duration of radio-fluorination of NITTP, not the radio-fluorination temperature favoured the formation of labeled thermally degraded product, but the single neutral alumina column purification was sufficient enough to obtain [18F]FMISO devoid of any radiochemical as well as cold impurities.

Methods and procedures for monitoring the consistency of sets of recommended data for radioactive nuclide decay characteristics are considered. A procedure is proposed, which combines three methods of checking the consistency of quantities related to the decay scheme of a radionuclide: the decay energy, the energies and probabilities of nuclear transitions, the internal conversion coefficients and the energies and emission probabilities of the radiations accompanying the decay.

Several older and recent reports provided evidence for the oscillatory character of the exponential decay law in radioactive decay and attempted to explain it with basic physics. We show here that the measured effects observed in some of the cases, namely in the decay of 226Ra, 32Si in equilibrium, and 36Cl, can be explained with the temperature variations.

The coincidence detection efficiency of the TUNL-ITEP apparatus designed for measuring half-life times of two-neutrino double-beta ( 2 ν β β ) decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the 100 Mo 2 ν β β decay to the first excited 0 1 + state in 100 Ru has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T 1 / 2 = [ 5.5 − 0.8 + 1.2 ( stat ) ± 0.3 ( syst ) ] × 10 20 yr . Measured 2 ν β β decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in 100 Ru which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics.

A new automated synthesis procedure of 1-H-1-(3-[18F]fluoro-2-hydroxypropyl)-2-nitroimidazole ([18F]FMISO), a specific hypoxia imaging agent with great significances for the noninvasive, dynamic hypoxia evaluation of cancer, was developed by modifying Explora FDG4 module, a commercial [18F]FDG production system, in this study. Its radiochemical synthesis was carried out via two sequent reaction steps, i.e. the nucleophilic displacement of labeling precursor 1-(2′-nitro-1′-imidazolyl)-2-O-tetrahydropyranyl-3-O-tosyl-propanediol (NITTP) with activated 18F- ion at 100 °C for 8 minutes, and the following hydrolysis with 1M HCl at 100 °C for 5 minutes and neutralization with 1M NaOH. Two-pot reaction with two independent separations was adopted to assure the good separation of final product via solid phase extraction (SPE) based upon combined Sep-pak cartridges instead of high performance liquid chromatography (HPLC). This fast, reliable preparation route of 18F-FMISO could complete within 50 minutes with about 55% of high radiochemical yield (with decay correction) and more than 98% of good radiochemical purity. The modified module could perform multiple runs of production of [18F]FMISO.

Measurements performed in searches for the double-beta decay of 136Xe showed an excess of events in exposures of a target enriched in the isotope 136Xe in relation to exposures of a target depleted in this isotope. The activation of xenon in the detector used under the effect of background neutron and muon radiation and the possible contribution of these processes to the results of relevant measurements are studied.

During radioactive decay of a collection of nuclides the possibility of the total activity increasing is implicit in the standard differential equations. Traditional treatments do not emphasize this possibility so leading to unease when such a rise is observed. Examples of increases in activity for materials following irradiation by neutrons are given, and the phenomenon is explored in a model system of three nuclides. Conditions on the decay constants and the initial number of atoms of the nuclides such that the total activity can increase with time are given.

Changes in the rate of the beta decay of radioactive elements whose periods are about 24 h and 27 d are detected on the basis of long-term investigations performed with the aid of scintillation and germanium-lithium gamma detectors. The use of the scintillation procedure yields results whose level of significance is much higher than 5%, while the procedure based on germanium—lithium detectors gives a more than 1% deviation from the average value of fluxes of gamma rays accompanying, for example, 60Co beta decay. With allowance for the rotation of the laboratory frame together with the Earth, deviations of the change in the rate of beta decay of radioactive elements single out three directions in the physical space.

The spatial distribution of neutrons was measured at the muon science laboratory of KEK by the activation detector method using an imaging plate for the radioactivity measurement. It was confirmed that this method is highly sensitive to detect the average neutron dose of 10 µSv/h. The distribution of thermal and epithermal neutrons was also measured in the experimental room. The cadmium ratio inside the experimental room is one except for the neutron leakage point. The spatial distribution of neutrons inside the concrete shield of KENS was measured by the same method. Aluminum and gold foils were used for the measurement of fast and thermal neutrons, respectively. Two dimensional change of the reaction rate of the 27Al(n,α)24Na reaction shows a good agreement with the results calculated by the Monte Carlo simulation using MARS14 code. Thermal and epithermal neutron flux ratio on the beam axis was measured by the cadmium ratio method. The flux ratios were about 30 and almost constant for every slot except for the surface of the shield, because the cadmium ratio is 2. This method was very useful to measure the activity of many pieces of detector simultaneously without any efficiency and decay correction. Wide dynamic range and high sensitivity are also the merit of this method.

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has resulted in the deposition of radioactive contamination of soils mainly by (134)Cs and (137)Cs. The contaminated areas are of a great concern since external radiation may lead to significant long-term doses to humans and animals. External dose rate above ground will decrease with physical decay of the radionuclides and as they migrate deeper into the soil with time. In the present study, depth profiles of Cs radioisotopes have been studied at different times over a period of 1 y. Radiocaesium inventories for (134)Cs and (137)Cs down to a depth of 10 cm at the four measurement times varied from 2.09 to 4.14 MBq m(-2) with coefficient of variation (CV): 27.4 %, n = 4 and from 2.13 to 4.23 MBq m(-2) with CV: 27.3 %, n = 4, respectively. The activity ratio for (134)Cs/(137)Cs decreased from 0.62 to 0.46 during 1 y of measurement i.e. July 2012 to June 2013. However, the ratio with decay correction (15 March 2011) was found to be constant ∼1, indicating contamination from FDNPP origin. In order to understand the radiocaesium distribution in soil profile, physico-chemical characterisation of soil has been carried out.

A method based on liquid scintillation counting system has been developed for the measurement of (90)Sr in Fukushima soil samples due to contamination of (134)Cs and (137)Cs. Three soil samples were collected within 30 km radius from the Fukushima Daiichi Nuclear Power Plant (FDNPP). Activity concentration of (134)Cs and (137)Cs were measured using a gamma spectroscopy system with high-purity germanium detector. (90)Sr contamination is little elevated but comparable with the background contamination level that originated from atmospheric nuclear weapon tests, whereas radiocesium contamination has increased significantly. Activity concentration of (90)Sr in the soil samples varied in the range of 10.4±0.6-22.0±1.2 Bq kg(-1). Activity concentrations of (134)Cs and (137)Cs in the soil samples were in the range of 28.2±0.2-56.3±0.2 kBq kg(-1) and 35.2±0.1-70.2±0.2 kBq kg(-1), respectively (reference date for decay correction is 1 December 2011).

An original decay correction procedure is proposed for the activity determination of short-lived radionuclides in airborne dust samples. To this end, the hypothesis of air flow rate attenuation during sampling is considered and tested. The other decay corrections: to the delay time, from the end of the sampling until the start of the counting; and to the counting time, were executed as standard. Differences from classic corrections, which consider a constant air flux rate in the sampling with a weekly sampling duration, are of the order of 1% for 7 Be and approximately 10% for 131 I. Moreover, the procedure can be applied to estimate the air volume sampled in the last 24 h before the end of the sampling. This volume can be used to calculate the activity concentration of a radionuclide (short-or long-lived radionuclide) if a major nuclear accident causes an instantaneous contamination immediately before the end of sampling.

Objectives: In ultra-short echo time (UTE) imaging, the transverse magnetization experiences significant decay during data acquisition, which gives rise to a loss of signal intensity and spatial resolution in conventionally reconstructed images. The present work proposes an iterative algorithm to correct these adverse effects. Materials and methods: The algorithm involves solving a large linear system of equations and requires a separate reference scan to map the spatially variant transverse relaxation time. It was implemented and applied to simulations and to experiments with custom-built resolution phantoms. The evaluation focused on its ability to improve the actual point-spread function (PSF) and on its influence upon the local signal-to-noise ratio (SNR). Results: The algorithm is demonstrated to virtually restore the ideal PSF of the acquisition. It proves to provide images with better signal intensity and spatial resolution but reduced SNR, if the transverse relaxation time is known with sufficient accuracy. Conclusions: The present work shows the basic feasibility of correcting signal decay effects in UTE imaging.

Independent analysis of the spectra from the Heidelberg-Moscow experiment has been carried out. A direct comparison of the peak intensities in the spectra allows for the conclusion that in the energy range up to 3200 keV the background is due to the detection of γ rays from the decay of trace impurities of anthropogenic and cosmogenic nuclides occurring in the apparatus between the HPGe detectors and the main (Pb and Cu) shielding. The 226Ra, 214Pb, and 214Bi γ rays observed in the spectra are shown to arise in the 226Ra rather than 238U decay chain. The estimates of the expected intensities of the weak 214Bi γ rays in the spectrum region around Qββ(76Ge) = 2039 keV do not contradict the observation of the peak at 2039 keV as claimed by Klapdor-Kleingrothaus and coauthors.

An evaluation of the complete scheme and data for 233 Pa decay, including results of the recent measurements, is presented. Several data evaluation procedures were used in the analysis of the half-life data. The half-life has been determined to be 26.971±0.013 days. All the gamma-ray emission probabilities ever published have been examined, and the gamma-ray emission probability for the reference 312-keV γ line is recommended as 38.35±0.28%. The calculated internal conversion coefficients and their uncertainties have been used to obtain the complete decay intensity balance. Other decay characteristics have been calculated using the ENSDF analysis program. Finally, a new 233 Pa decay scheme has been built.