Search

One of the most influential alchemical authors of the early modern period was Michael Sendivogius whose early life is shrouded in mystery. He may be labelled the most famous Polish scientific writer between Copernicus and Marie Skłodowska-Curie, but because of the difficulties involved in researching the biography of any alchemist, there has been relatively little interest in him among Polish historians. The early work of Roman Bugaj (author of the still fundamental monograph) and Włodzimierz Hubicki (who made his research available to the international community) has been continued only by the English-born Zbigniew Szydło and the author of this article. The roots of many legends about Sendivogius were three mid-17th century short biographies, none of which is trustworthy, so it is crucial to verify the received myth and the version constructed in the 1960's and 1970's with primary sources and evidence from the recent "new historiography of alchemy". The present article examines them in the light of newly discovered sources and reinterpretation of the old ones. The genealogy of the Seędzimir family is discussed at length to show that Sendivogius most probably was not its member but only a pretender in order to assume (or prove) the status of a nobleman. Several possible hypotheses about his origins are presented. He is known to have studied at three universities (Leipzig, Vienna and Altdorf) but authors of early panegyrics dedicated to Sendivogius list more universities which he may have attended. The most interesting is that of Cambridge, listed as the first one, because practically no Poles or Czechs went there at the time. Finally, his marriage to Veronica Stiebar, a wealthy widow of a Franconian knightly family, and her interesting family relationships (links to Erasmus, Camerarius, Paracelsus and the original Doctor Faustus) are discussed. The period covered is that before Sendivogius moved to Prague in about 1597, having already been a courtier of Rudolf II since early 1594. [ABSTRACT FROM AUTHOR]

Abstract: A technique for precise control of ion injection into a Penning trap is presented, based on the employment of an drift motion of the ion in the strong magnetic field in which the Penning trap is located. An electric dipole field with variable strength and orientation allows for precise placement of the ion in the radial plane of the trap. This method allows for fast preparation of an ion’s magnetron motion, as used, for example, in the time-of-flight cyclotron resonance detection technique. [Copyright &y& Elsevier]

The emanation of radionuclides has been highlighted as a known source of uncertainty in the estimation of radionuclide source signatures from underground nuclear tests and other nuclear activities, particularly in the case of activation products. A system was developed at Pacific Northwest National Laboratory to quantify the emanation of argon from two powders and five rock types ranging in particle size from powder to small rocks. Samples were neutron irradiated and the percent emanation of 37Ar was measured to range between 0.3 and 25%. Measurements were also made of the 39Ar emanation for four of these materials and was found to be consistently lower than that of 37Ar. [ABSTRACT FROM AUTHOR]

We evaluate the ability of the Canberra Alpha Beta Environmental Continuous Air Monitor (ECAM) to detect and quantify airborne radiological contamination. The ECAM essentially consists of a passively-implanted planar silicon (PIPS) detector near a particulate filter through which outside air is pulled. Three years' worth of background measurements on three different systems were assessed and calibrated to compensate for changing conditions and develop an average background response for the systems. The ECAM was also exposed to several radionuclides of interest, including 235U and 239Pu, to measure the response to alpha and beta particle sources. Both standard calibration sources and custom sources consisting of aqueous radioisotope solutions absorbed into clean filters. The ECAM responses to these sources were then scaled to quantities of interest and injected on the averaged background. Various alarm algorithms were evaluated on the source-injected spectra for minimum detectable air concentration for a given false alarm rate. Even in the worst case, the ECAM was able to detect radionuclides of interest at 10% of the Derived Response Level (DRL) for each isotope based on early-phase Protective Action Guides (PAG). Quantification of the radionuclides was also evaluated for the various algorithms, with mixed results, but overall clearly indicating the optimal algorithms for alpha and beta particle alarm and quantification. Finally, a limited evaluation of the beta particle detection efficiency points to a detection energy threshold of approximately 290 keV. • Continuous air monitor able to measure airborne isotopes of concern to 10% of derived response levels or less. • Summing counts in a single region of interest produces best sensitivity to alpha emitters. • Predicting beta counts based on background alpha counts and decay chains produces the best sensitivity to beta emitters. • Beta particle lower energy threshold estimated to be approximately 290 keV for planar silicon detector. [ABSTRACT FROM AUTHOR]

Two isotopically-characterized targets of high-purity (99.961±0.002%) 238U metal and a neutron dosimetry package were exposed to a pulsed neutron irradiation using the Godiva IV critical assembly at the National Criticality Experiments Research Center to measure the integral fission product yields produced in a Watt fission neutron-energy spectrum. Following irradiation, the fissioned targets were counted with two broad energy germanium detectors. Estimates of the total fissions for each target were made using measurements of well-known fission products. The total number of fissions in each target were then used to measure the fission yields of 33 fission products, 18 of which are published as new measurements. Twelve of the 18 isotopes were in agreement with ENDF/B-VIII.0 using the zeta test and treating ENDF/B-VIII.0 as the true mean: 84mBr, 93Y, 94Y, 104Tc, 134I, 135I, 138Xe, 141Ba, 142Ba, 142La, 146Ce, and 149Nd. The ENDF/B-VIII.0 fission yield for 139Ba was only slightly outside of 1- σ relative to the uncertainty measured in this work. Uncertainties for 5 fission product yields were markedly improved over those reported in ENDF/B-VIII.0: 128Sn, 129Sb, 130gSb, 131mTe, and 133I. The fission yields measured for 128Sn, 131mTe, and 133I were in good agreement with the ENDF/B-VIII.0 predicted fission yields. However, fission yields measurements of the isotopes 129Sb, and 130gSb deviated from the ENDF/B-VIII.0 value. Both of these isotopes reside near the doubly magic nuclear shell closures of 50 protons and 82 neutrons. These fission yields may be suppressed because of the odd-odd nuclear structure of 130gSb and the odd-even structure of 129Sb and isomer splitting. Comparisons to other recent work and a brief review with citations are included to support this conclusion. [ABSTRACT FROM AUTHOR]

Abstract Radioxenon detection is an important component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty. We developed and validated a new model in MCNPX-PoliMi to simulate the decay of various radioxenon isotopes and the detector response of a variety of detector types. The model was validated using calibration data from a plastic and NaI(Tl) beta–gamma coincidence detector and the results are presented. The results of this validation show that this model can also be used as a tool to produce training spectra and as a method to calibrate radioxenon detection systems. [ABSTRACT FROM AUTHOR]

Radioxenon emissions from fission-based radiopharmaceutical production are a major source of background concentrations affecting the radioxenon detection systems of the international monitoring system (IMS). Collection of real-time emissions data from production facilities makes it possible to screen out some medical isotope signatures from the IMS radioxenon data sets. This paper describes an effort to obtain and analyze real-time stack emissions data with the design, construction and installation of a small stack monitoring system developed by a joint CTBTO-IDC, BATAN, and Pacific Northwest National Laboratory team at the BaTek medical isotope production facility near Jakarta, Indonesia. [ABSTRACT FROM AUTHOR]

Fission product yields are critical data for a variety of nuclear science and engineering applications; however, independent yields have not been extensively measured to date. We have previously documented a methodology to measure the cumulative and independent fission product yields using gamma spectrometry and nuclide buildup and decay modeling, and numerical optimization. We have produced fission products by bombarding U with 14.1 MeV neutrons and made measurements of fission product yields. In this paper, we summarize our approach, describe initial experiments, and present preliminary results where we have determined nine fission product yields for long-lived nuclides. [ABSTRACT FROM AUTHOR]

PNNL developed a beta-gamma simulator (BGSim) that incorporated GEANT-modeled data sets from radioxenon decay chains, as well as functionality to use nuclear detector-acquired data sets to create new beta-gamma spectra with varying amounts of background, Xe, Xe, Xe, Xe, and Rn and its decay products. After BGSim was developed, additional uses began to be identified for the program output: training sets of two-dimensional spectra for data analysts at the IDC and other NDC, and spectra for exercises such as the Integrated Field Exercise 2014 held in Jordan at the Dead Sea. [ABSTRACT FROM AUTHOR]

A Noble Gas Migration Experiment injected Xe, Ar, and sulfur hexafluoride into a former underground nuclear explosion shot cavity. These tracer gases were allowed to migrate from the cavity to near-surface and surface sampling locations and were detected in soil gas samples collected using various on-site inspection sampling approaches. Based on this experiment we came to the following conclusions: (1) SF was enriched in all of the samples relative to both Ar and Xe. (2) There were no significant differences in the Xe to Ar ratio in the samples relative to the ratio injected into the cavity. (3) The migratory behavior of the chemical and radiotracers did not fit typical diffusion modeling scenarios. [ABSTRACT FROM AUTHOR]

Beta-gamma coincidence radioxenon detectors must be calibrated for each of the four-radioxenon isotopes (Xe, Xe, Xe, and Xe). Without a proper calibration, there is potential for the misidentification of the amount of each isotope detected. It is important to accurately determine the amount of each radioxenon isotope, as the ratios can be used to distinguish between an anthropogenic source and a nuclear explosion. We have developed a xenon calibration system (XeCalS) that produces calibration spikes of known activity and pressure for field calibration of detectors. We will present results from the development of XeCalS and a portable spike implementation system. [ABSTRACT FROM AUTHOR]

We present a novel technique for the localization of radiological sources in urban or rural environments from an aerial platform. The technique is based on a Bayesian approach to localization, in which measured count rates in a time series are compared with predicted count rates from a series of pre-calculated test sources to define likelihood. This technique is expanded by using a localized treatment with a limited field of view (FOV), coupled with a likelihood ratio reevaluation, allowing for real-time computation on commodity hardware for arbitrarily complex detector models and terrain. In particular, detectors with inherent asymmetry of response (such as those employing internal collimation or self-shielding for enhanced directional awareness) are leveraged by this approach to provide improved localization. Results from the localization technique are shown for simulated flight data using monolithic as well as directionally-aware detector models, and the capability of the methodology to locate radioisotopes is estimated for several test cases. This localization technique is shown to facilitate urban search by allowing quick and adaptive estimates of source location, in many cases from a single flyover near a source. In particular, this method represents a significant advancement from earlier methods like full-field Bayesian likelihood, which is not generally fast enough to allow for broad-field search in real time, and highest-net-counts estimation, which has a localization error that depends strongly on flight path and cannot generally operate without exhaustive search. [ABSTRACT FROM AUTHOR]

Background: Gamow-Teller (GT) transition strengths are key inputs for estimating weak reaction rates of importance for a wide variety of astrophysical applications. (n,p)-type charge-exchange reactions, such as the (t³He) reaction used in this work, are commonly used for extracting the GT strength distribution in the β+(electron-capture) direction. Such studies are important for testing theoretical models used to estimate weak rates for a large number of nuclei for simulations of astrophysical phenomena Purpose: The 56Fe(t,³He) reaction at 115 A MeV was measured in order to extract GT strengths for transitions to 56Mn. The extracted strength distributions were compared with shell-model calculations in the p/-shell model space using the KB3G and GXPFla interactions, and with calculations in the quasi-particle random-phase approximation (QRPA). Method: Differential cross sections and excitation-energy spectra for the 56Fe(t, ³He) reaction were determined by measuring the trajectories of ³He ejectiles through the S800 magnetic spectrograph and deducing their momenta. Contributions corresponding to GT transitions were isolated by using a multipole decomposition analysis. A well-established proportionality between GT strength and differential cross section at zero-linear-momentum transfer was utilized to convert extracted cross sections to GT strengths. Results and Conclusions: GT transition strengths from 56Fe to 56Mn were extracted up to an excitation energy of 10 MeV. Shell-model calculations with the GXPFla interaction reproduced the observed GT strength distribution slightly better than calculations with the KB3G interaction. The calculated strength distribution in the QRPA did not reproduce the observed strength distribution. The new experimental data have an improved precision at low excitation energies compared to previous results obtained from an 56Fe(n,p) experiment. Electron-capture rates based on the experimental and theoretical Gamow-Teller strengths were compared and deviations were included in an assessment of the validity of electron-capture rates based on theoretical models for nuclei in the pf shell. [ABSTRACT FROM AUTHOR]

Background: Gamow-Teller (GT) transition strength distributions in stable and unstable pf '-shell isotopes are key inputs for estimating electron-capture rates important for stellar evolution. Charge-exchange experiments at intermediate beam energies have long been used to test theoretical predictions for GT strengths, but previous experiments were largely restricted to stable nuclei. Since a large fraction of the nuclei relevant for astrophysical applications (including key nuclei such as56Ni) are unstable, new methods are needed to perform charge-exchange experiments in inverse kinematics with unstable isotopes. Purpose: The 56Ni(p, n) and 55Co(p, n) reactions were measured in inverse kinematics in order to extract GT strengths for transitions to 56Cu and 55Ni, respectively. The extracted strength distributions were compared with shell-model predictions in the pf shell using the KB3G and GXPF1J interactions. By invoking isospin symmetry, these strength distributions are relevant for electron captures on the ground states of 56Ni and 55Ni to final states in 56Co and 55Co, respectively. Method: Differential cross sections and excitation energy spectra for the 56Ni(p, n) and 55Co(p, n) reactions were determined by measuring neutrons recoiling from a liquid hydrogen target into the Low Energy Neutron Detector Array. GT contributions to the spectra were extracted by using a multipole decomposition analysis and were converted to strengths by employing the proportionality between GT strength and differential cross section at zero linear momentum transfer. Results: GT strengths from 56Ni and 55Co were extracted up to excitation energies of 8 and 15 MeV, respectively. Shell-model calculations performed in the pf shell with the GXPF1J interaction reproduced the experimental GT strength distributions better than calculations with the KB3G interaction. Conclusions: A new technique for measuring (ρ, ?) charge-exchange reactions on unstable nuclei was successfully developed. It can be used to study the isovector response of unstable nuclei in any mass region and for excitation energies beyond the particle decay threshold. In the first experiment, 56Ni(/?, n) and55Co(p, n) reactions were studied and GT transition strengths were extracted for the purpose of testing shell-model calculations used to estimate electron-capture rates in simulations of late stellar evolution. The calculation using the GXPF1J interaction was found to best reproduce the experimental strength distribution. [ABSTRACT FROM AUTHOR]

We present a novel technique for studying the quenching of shell gaps in exotic isotopes. The method is based on extracting Gamow-Teller (&Dgr;L = 0, &Dgr;S = 1) transition strengths [B(GT)] to low-lying states from charge-exchange reactions at intermediate beam energies. These Gamow-Teller strengths are very sensitive to configuration mixing between cross-shell orbitals, and this technique thus provides an important complement to other tools currently used to study cross-shell mixing. This work focuses on the N = 8 shell gap. We populated the ground and 2.24 MeV 0+ states in 12Be using the 12B(1+) (7Li, 7Be) reaction at 80 MeV/u in inverse kinematics. Using the ground-state 5(GT) value from ß-decay measurements (0.184 ± 0.007) as a calibration, the B(GT) for the transition to the second 0+ state was determined to be 0.214 ±0.051. Comparing the extracted Gamow-Teller strengths with shell-model calculations, it was determined that the wave functions of the first and second 0+ states in 12Be are composed of 25 ± 5% and 60 ± 5% (0s)4(0p)8 configurations, respectively. [ABSTRACT FROM AUTHOR]

A new technique to measure (p, n) charge-exchange reactions in inverse kinematics at intermediate energies on unstable isotopes was successfully developed and used to study the 56Ni(p, n) reaction at 110 MeV/u. Gamow-Teller transition strengths from 56Ni leading to 56Cu were obtained and compared with shell-model predictions in the pf shell using the KB3G and GXPF1A interactions. The calculations with the GXPF1A interaction reproduce the experimental strength distribution much better than the calculations that employed the KB3G interaction, indicating deficiencies in the spin-orbit and proton-neutron residual potentials for the latter. The results are important for improving the description of electron-capture rates on nuclei in the iron region, which are important for modeling the late evolution of core-collapse and thermonuclear supernovae. [ABSTRACT FROM AUTHOR]

Rare isotope beams of many elements can be difficult or impossible to obtain at ISOL facilities due to their high melting points or chemical reactivity, but they are easily produced by projectile fragmentation and in-flight separation, a technique that rapidly produces fragments lighter than the projectile in a chemistry-free manner. Until recently, such high-energy projectile fragments could not be reduced to the thermal energies necessary for precision mass measurements in Penning traps. The Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory (NSCL) has demonstrated that projectile fragment beams can be thermalized and measured in a high-precision Penning trap. Since 2005, over 30 isotopes have been measured with LEBIT, including several isotopes of elements which are difficult for ISOL facilities to produce, such as Fe, Co, Si, Br, and S. These measurements have contributed to our understanding of nuclear structure, nuclear astrophysics, and fundamental symmetries. Some recent highlights include the discovery of an isomeric state in Fe, testing the Isobaric Mass Multiplet Equation (IMME) with the A = 32, T = 2 quintet with a measurement of Si, probing out to the proton dripline with Br, and studying the N = 28 shell closure with measurements of S. Results of these measurements will be discussed, along with the technical developments which made them possible. [ABSTRACT FROM AUTHOR]

The low-energy beam and ion trap facility LEBIT at NSCL/MSU is at present the only facility where precision experiments are performed with stopped rare isotope beams produced by fast-beam fragmentation. LEBIT combines high-pressure-gas stopping with advanced ion manipulation techniques to provide brilliant low-energy beams. So far these beams have mainly been used for mass measurements on short-lived rare isotopes with a 9.4T Penning trap mass spectrometer. Recent examples include 70 mBr , located at the proton dripline, 32Si and the iron isotopes 63-65Fe . While the measurement of 32Si helps to solve a long-standing dispute over the validity of the isobaric multiplet mass equation (IMME) for the A = 32 , T = 2 multiplet, the mass measurements of 65 m,gFe marked the first time a nuclear isomeric state has been discovered by Penning trap mass spectrometry. [ABSTRACT FROM AUTHOR]

Abstract: The Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory (NSCL) was the first to demonstrate that high-accuracy nuclear physics experiments at low energy can be performed on rare isotopes produced by fast-beam fragmentation. The LEBIT system combines gas stopping of fast-fragment beams and advanced ion-beam manipulation and purification techniques with a 9.4-T Penning trap mass spectrometer. In operation since 2005, the masses of about thirty rare isotopes on both sides of the valley of stability have been measured at LEBIT. The investigated nuclei include the super-allowed beta emitter 38Ca, several N = Z nuclei such as the rp process waiting point nuclei 64Ge and 68Se, and the drip line nucleus 70m Br. The very accurate mass values obtained at LEBIT contribute to the understanding of astrophysical nucleosynthesis, nuclear structure studies, and tests of the Conserved-Vector-Current (CVC) hypothesis. [Copyright &y& Elsevier]

Abstract: The NSCL gas-stopping station thermalizes high-energy projectile fragments for study in the low energy beam and ion trap (LEBIT) facility. The stopping and extraction of fast beams has been studied extensively and the extracted short-lived ions have been used in a series of mass measurements of exotic nuclei. Particle-in-cell simulations of ion drift in the gas cell have been performed. In the present paper calculation results are presented and compared to experimental data obtained with neutron-deficient and neutron-rich As and Se isotopes recently measured at LEBIT. Good agreement between the theoretical and experimental extraction efficiency was found. [Copyright &y& Elsevier]

A linear gas stopping cell has been implemented at the NSCL as part of the Low Energy Beam and Ion Trap (LEBIT) facility. The gas stopping cell is used to convert relativistic ions into low energy ions suitable for use in ion trap experiments. A common undesired property of such systems is the production of beam contaminants through charge exchange of gas impurities with the He + ions produced in the stopping process. These contaminants are of particular concern for Penning trap mass spectrometry, where the simultaneous trapping of ions with different masses can cause unwanted shifts in the measured cyclotron frequency of the desired ions. In order to minimize such effects, a multi-stage beam purification system has been implemented at LEBIT. [ABSTRACT FROM AUTHOR]

The low-energy beam and ion trap facility LEBIT at the NSCL at MSU has demonstrated that rare isotopes produced by fast-beam fragmentation can be slowed down and prepared such that precision experiments with low-energy beams are possible. For this purpose high-pressure gas-stopping is employed combined with advanced ion manipulation techniques. Penning trap mass measurements on short-lived rare isotopes have been performed with a 9.4 T Penning trap mass spectrometer. Examples include 66As, which has a half-live of only 96 ms, and the super-allowed Fermi-emitter 38Ca, for which a mass accuracy of 8 ppb (280 eV) has been achieved. The high accuracy of this new mass value makes 38Ca a new candidate for the test of the conserved vector current hypothesis. [ABSTRACT FROM AUTHOR]

Abstract: The low-energy beam and ion trap facility (LEBIT), has been designed to facilitate a variety of experiments at low energies with rare isotopes produced by fast-beam fragmentation. Gas stopping of the fast-fragment beams and modern ion manipulation techniques are used. The first experiments to be performed are high-precision mass measurements possible with a 9.4 T Penning trap mass spectrometer. LEBIT has been recently commissioned and first experiments on stable and unstable nuclides have been performed. Here we present the results of mass measurements on stable krypton isotopes, measured with a precision of better than that reveal significant deviations from the literature values for and . The paper also provides an overview of LEBIT and the first Penning trap mass measurements performed on unstable isotopes from fast-beam fragmentation. [Copyright &y& Elsevier]

High-precision Penning-trap mass measurements of the N approximately Z approximately 34 nuclides 68Se, 70Se, (70m)Br, and 71Br were performed, reaching experimental uncertainties of 0.5-15 keV. The new and improved mass data together with theoretical Coulomb displacement energies were used as input for rp process network calculations. An increase in the effective lifetime of the waiting point nucleus 68Se was found, and more precise information was obtained on the luminosity during a type I x-ray burst along with the final elemental abundances after the burst.

A new long-lived isomeric state in (65)Fe has been discovered with Penning trap mass spectrometry and high-precision mass measurements of the neutron-rich isotopes (63-65)Fe and (64-66)Co have been performed with the Low-Energy Beam and Ion Trap Facility at the NSCL. For the new isomer in (65)Fe an excitation energy of 402(5) keV has been determined from the measured mass difference between the isomeric and ground states. The mass uncertainties of all isotopes have been reduced by a factor of 10-100 compared to previous results. In the case of (64)Co the previous mass value was found to deviate by about 5 standard deviations from the new measurement.