LENDA, a Low Energy Neutron Detector Array for experiments with radioactive beams in inverse kinematics

The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight (TOF) spectrometer developed at the National Superconducting Cyclotron Lab- oratory (NSCL) for use in inverse kinematics experiments with rare isotope beams. Its design has been motivated by the need to study the spin-isospin response of unstable nuclei using (p, n) charge-exchange reactions at intermediate energies (> 100 MeV/u). It can be used, however, for any reaction study that involves emission of low energy neutrons (150 keV - 10 MeV). The array consists of 24 plastic scintillator bars and is capable of registering the recoiling neutron energy and angle with high detection efficiency. The neutron energy is determined by the time-of-flight technique, while the position of interaction is deduced using the timing and energy information from the two photomultipliers of each bar. A simple test setup utilizing radioactive sources has been used to characterize the array. Results of test measurements are compared with simulations. A neutron energy threshold of < 150 keV, an intrinsic time (position) resolution of \sim 400 ps (\sim 6 cm) and an efficiency > 20 % for neutrons below 4 MeV have been obtained.Comment: Version accepted for publication in Nucl. Instr. Methods A. Revised text, 2 new figures added (one in section 4 and one in section 7

Alchemical patronage and the making of an adept: letters of Michael Sendivogius to Emperor Rudolf II and his chamberlain Hans Popp

Based on four extant letters the famous Polish alchemist Michael Sendivogius wrote to Emperor Rudolf II and his first chamberlain Hans Popp between 1597 and 1602, this paper adds to a growing body of revisionist scholarship on alchemy in Rudolfine Prague. Unlike most of his many rivals - including luminaries such as John Dee and Michael Maier - who hoped for the Emperor's patronage in vain, Sendivogius officially became a courtier at the imperial court in 1594. As such he was in the privileged position of having access to the Emperor and his close advisors. The surviving correspondence shows how the Pole successfully balanced his alchemical promises against Rudolf's expectations for a number of years. The fact that even Sendivogius found it difficult to translate imperial patronage into ready money suggests that Emperor Rudolf II was considerably more circumspect and less gullible than the widespread cliche suggests. Fully contextualised by all available sources on Sendivogius' early career, the four letters emerge as important documents regarding the Polish adept and alchemical patronage in Rudolfine Prague. They also shed new light on the circumstances which led to the writing and publication of Sendivogius' famous treatise De lapide philosophorum (Novum lumen chymicum)

ArchTerra: Extending the European Archaeology Web over Bulgaria, Romania, and Poland

From the beginning of 1999 until the end of 2000, the ArchTerra(1) project (an International co-operation Project under the EU Copernicus programme) has been active in the creation of an Internet infrastructure and content for Central European archaeology. This paper provides a brief overview of its goals and current results.</p

"Learn to restrain your mouth": Alchemical rumours and their historiographical afterlives

From around 1700 onwards, a number of sensationalist claims regarding adepts of the sixteenth and early seventeenth centuries began to appear in alchemical literature. They eventually made their way into standard works of historiography and continue to be repeated as factual. Yet the source for these rumours, a poem attributed to Martinus de Delle, supposedly a chamberlain of Emperor Rudolf II, has largely escaped scrutiny. The only surviving manuscript version currently known is here edited and translated in full for the first time. In the introductory essay, we call into question the existence of De Delle. Through scrutiny of the portrayals of alchemists within the poem, we propose that the author may have been an assayer in Prague. We then draw attention to the roles and effects of rumours within both the history and historiography of alchemy and argue for the importance of taking alchemical gossip seriously

Mistaken identity, forged prophecies, and a Paracelsus commentary: the elusive Jewish alchemist Mardochaeus de Nelle

The impressive career of the mysterious Jewish adept and prophet Mardochaeus de Nelle is well known among specialists in Judaism and early modern science or the history of alchemy. Hailing from Italy, he was allegedly active at leading courts of the late sixteenth century—including those of Elector August in Dresden and Emperor Rudolf II in Prague—and several alchemical texts circulated under his name. Based on thorough scrutiny of all currently known sources in print and especially in manuscript, we conclude that most of them were falsely associated with De Nelle due to a case of mistaken identity and a late eighteenth century forgery. Only the oldest sources, four manuscript versions of a Paracelsus commentary, may perhaps shed light on De Nelle’s biography and place him in Reichenstein (1567), Speyer (1570), and Cracow (1573). On balance, however, the internal evidence suggests that we are dealing with a case of pseudepigraphy. De Nelle’s example shows why it is imperative to examine all extant manuscript versions of relevant texts and take into consideration the cultural stereotypes that inform these sources

PACHO - A Semantic P2P Network for Virtual Reality based Heritage Objects and Resources

No description supplie

Validation of MCNPX-PoliMi code for simulations of radioxenon beta–gamma coincidence detection

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

Measurements of the emanation of Ar-37 and Ar-39 from irradiated rocks and powders

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 Ar-37 was measured to range between 0.3 and 25%. Measurements were also made of the Ar-39 emanation for four of these materials and was found to be consistently lower than that of Ar-37

Precision experiments with rare isotopes with LEBIT at MSU

The Low-Energy Beam and Ion Trap facility LEBIT at the NSCL is in the final phase of commissioning. Gas stopping of fast fragment beams and modern ion manipulation techniques are used to provide beams for high-precision mass measurements and other experiments. The status of the facility and the result of first test mass measurements on stable krypton isotopes are presented