Search

Due to physical decay properties commonly associated with therapeutic radionuclides, 188Re (t 1/2 = 16.98 h, E max = 2.12 MeV) is of high interest for endovascular brachytherapy and endoradiotherapy in general. Rhenium precursors in the low oxidation state +I, such as the organometallic fac-[Re(H2O)3(CO)3]+ are promising lead compounds compared to those with oxidation states +III and +V since they can be prepared under mild conditions and do not tend to reoxidize to oxidation state +VII while multidentate ligands can be attached under substitution of coordinated water molecules. This study comprises the application of the Free-Ion Selective Radiotracer Extraction (FISRE) technique in order to determine dissociation rate constants of complexes bearing the [188Re(CO)3]+-core at tracer levels in vitro with regards to their time-dependent kinetic speciation. As ligands, the tridentate l-histidine as well as the dipeptides l-carnosine (β-alanyl-l-histidine) and glycyl-l-histidine were chosen in order to study the effects of different moieties attached to the primary amine of l-histidine.

Free-ion selective radiotracer extraction (FISRE) is a technique combining ion exchange and the use of radiotracers in order to determine labilities of metal complexes. The aminocarboxylate chelates 90Y-EDTA, 90Y-DTPA as well as 90Y-DOTATOC, a radiopharmaceutical for neuroendocrine tumor treatment have been studied by FISRE using Chelex cation exchanger within the pH range 5.0–7.4. Time-dependent speciation and dissociation rate constants have been determined in a time frame of 0.6 s–648 h. As indicated by thermodynamic constants, the lability decreases significantly with higher ligand denticity, cyclic coordination and upon peptide coupling resulting in the lability order Y-EDTA>Y-DTPA>Y-DOTA>Y-DOTATOC. Besides, studies of the effects of the metal/ligand ratio on FISRE suggest that – in contrast to EDTA and DTPA – cyclic ligands DOTA and DOTATOC tend to shield the ion exchanger from free yttrium ions after complex dissociation even at slight excess of metal ions. Copyright © 2008 John Wiley & Sons, Ltd.

Representative banded iron-formations (BIFs) from various locations of the eastern Indian geological belt were investigated by instrumental neutron activation analysis (INAA). After pre-concentration, irradiation was carried out using a neutron flux of 5.1·1016 m−2·s−1, 1.0·1015 m−2·s−1 and 3.7·1015 m−2s−1, with thermal, epi-thermal and fast neutrons, respectively. The activities in these samples were measured by a HPGe detector. Ten rare-earth elements, such as La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu, have been qualitatively identified and quantitatively estimated in these samples. The present investigation is an example of employing a pre-concentration method for high iron-containing ores prior to neutron activation analysis.

Cryosublimation is one technique, which allows the accumulation of tritium from aqueous solutions using certain chemical compounds. After studying several inorganic compounds such as zeolites and metal salts,1 as well as some humic substances,2 we have now investigated several mono-and polysaccharides, such as glucose, maltose, galactose, starch, agar, and gelatine. Except for starch all of the above mentioned compounds showed a clear enrichment of tritium. The highest value was reached for Agartine, which gave an enrichment factor of 6.2. Since mono-and polysaccharides form weak hydrogen bonds, these results prove again our theory that tritium is preferably accumulated in exchangeable hydrogen bonds.

Within this work the analysis of the kinetic stability of a series of yttrium complexes, i.e., Y-citrate, Y-NTA, Y-CDTA as well as Y-humic acid (Y-HA) has been successfully performed by the free-ion selective radiotracer extraction (FISRE) method. FISRE uses 90Y with a high specific activity to perform CHELEX extractions in a buffered aqueous solution at pH 6 in two different modes by monitoring the dissociation and association reactions of the corresponding complexes. Whereas in the case of Y-citrate the dissociation profile could be successfully described in terms of (pseudo) first order kinetics, the other complexes tend to form two species with different kinetic properties, although only one species is predicted by speciation calculations. In the batch FISRE method, all (except Y-NTA) corresponding association rate constants were determined by monitoring the formation rate of the yttrium complexes.

A bipolar electrolysis system for tritium accumulation and HTO waste volume reduction was designed and built. Experiments were performed to achieve the system specific separation factor for iron and stainless steel cathodes in a 1M sodium hydroxide solution. A separation factor of about 6 for stainless steel and 19 to 26 for iron was measured. The vapor pressure isotope effect under experimental conditions was determined as 1.09±0.03 (T = 279 K).

Immobilization of organometallic complexes in thin supported films of ionic liquid has been used to generate a new class of hydroamination catalysts. High activities for the addition of aniline to styrene were obtained with a bi-functional system comprising [Pd(DPPF)](CF3CO2)2 and CF3SO3H immobilized in silica supported imidazolium salts. In this environment, the metal complexes are concluded to be enclosed in solvent cages of ion pairs of the ionic liquid. With increasing temperature, the imidazolium cations gain mobility until the solvent cages break down at a specific temperature, which is noticeable as phase transition. At temperatures below the phase transition, the catalytic activity was strongly influenced by the choice of the ionic liquid. At temperatures above the phase transition, the activity for formation of the Markownikoff product was, in contrast, nearly identical with all ionic liquids tested. Under these conditions, also the formation of the anti-Markownikoff product was observed.

In several experimental techniques D2O rather then H2O is often used as a solvent for proteins. Concerning the influence of the solvent on the stability of the proteins, contradicting results have been reported in literature. In this paper the influence of H2O-D2O solvent substitution on the stability of globular protein structure is determined in a systematic way. The differential scanning calorimetry technique is applied to allow for a thermodynamic analysis of two types of globular proteins: hen's egg lysozyme (LSZ) with relatively strong internal cohesion ("hard" globular protein) and bovine serum albumin (BSA), which is known for its conformational adaptability ("soft" globular protein). Both proteins tend to be more stable in D2O compared to H2O. We explain the increase of protein stability in D2O by the observation than D2O is a poorer solvent for nonpolar amino acids than H2O, implying that the hydrophobic effect is larger in D2O. In case of BSA the transitions between different isomeric forms, at low pH values the Nm and F forms, and at higher pH values Nm and B, were observed by the presence of a supplementary peak in the DSC thermogram. It appears that the pH-range for which the Nm form is the preferred one is wider in D2O than in H2O. (c) Wiley Periodicals, Inc.

Summary Two experiments aiming at the chemical investigation of element 112 produced in the heavy ion induced nuclear fusion reaction of 48Ca with 238U were performed at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt, Germany. Both experiments were designed to determine the adsorption enthalpy of element 112 on a gold surface using a thermochromatography setup. The temperature range covered in the thermochromatography experiments allowed the adsorption of Hg at about 35 °C and of Rn at about -180 °C. Reports from the Flerov Laboratory for Nuclear Reactions (FLNR), Dubna, Russia claim production of a 5-min spontaneous fission (SF) activity assigned to 283112 for the 238U(48Ca,3n) 283112 reaction. Hence, Experiment I was designed to detect spontaneously fissioning (SF) isotopes of element 112 with half-lives (t 1/2) longer than about 20 s. 11 high-energy events were detected. 7 events exhibit a deposition pattern resembling a chromatographic peak in the vicinity of Rn deposition. However, the energy of the events observed in Experiment I was lower than expected for a SF-decay of 283112. Therefore, these events could not be unambiguously attributed to the decay of 283112. In contradiction with earlier publications newer reports from FLNR Dubna claim that 283112 decays by α-particle emission (E α = 9.5 MeV) with t 1/2 = 4 s followed by a SF-decay of 279Ds (t 1/2 = 0.2 s). Therefore, Experiment II was designed to be sensitive to both claimed decay properties of 283112. However, during this experiment neither short α-SF correlations nor SF coincidences were detected. The conclusion is that 283112 was not unambiguously detected, neither in Experiment I nor in Experiment II.

182Hf (T(1/2) = 9 x 10(6) y) is believed to be formed by pure r-process during a supernova explosion, and therefore, the search for minute traces of 182Hf in the earth's crust is of great interest. Only accelerator mass spectrometry (AMS) is well suited for detecting such low levels of 182Hf. But any attempt to measure 182Hf by AMS must ensure that the sample is free from its naturally occurring stable isobar 182W. A simple method for separation of tungsten and hafnium has been developed using radiometric simulation followed by checking the decontamination of tungsten from Hf in a synthetic sample by AMS. The separation studies were performed by a liquid-liquid extraction technique using tri-n-octylamine (TOA) as the organic reagent. It has been found that a very high separation factor (1.6 x 10(6)) can be achieved when 0.3 M TOA diluted in cyclohexane is used as the organic phase and 6 M HCl (in the presence of small amount of H2O2) is used as the aqueous phase.

Tritium exchange and enrichment was studied for several different metal salts, e.g., AlF3 . H2O, FeO(OH), CsI, CsF, NaI, NaF and Al(OH)3 using a cryosublimation apparatus. Experiments were performed below equilibrium vapor pressure to avoid any isotope effects. A comparable tritium enrichment factor of 1.14 to 1.43 was obtained for all systems, except for CsF, which gave an enrichment factor of 1.93. These results confirm the concept, that 3H is accumulated in weak hydrogen bonds as already observed in organic molecules.

Humic and fulvic acid can be combined under the term 'humic substances' and are natural substances with a complex structure. The structural details are not known, however, due to the functional groups present in these compounds the formation of hydrogen bonds is easily attained. Several humic substances were investigated for their potential use as compounds, which are applicable for tritium enrichment from aqueous solution. For comparison a simple compound, malonic acid, representing only few functional groups was investigated. The experiments were performed using a cryosublimation apparatus, which was run well below equilibrium vapor pressure to avoid any isotope fractionation of HTO and H{sub 2}O. A higher enrichment factor was found for natural humic acid compared to fulvic acid, however, no enrichment could be found for a synthetic humic acid and malonic acid. Interpretation of the results is difficult since no detailed information on the chemical structure of humic substances is known.

Bovine serum albumin (BSA) and lysozyme (LSZ) were radiolabeled with 125I. Three different methods for protein iodination with 125I were optimized. Parameters like incubation time and ratio of oxidizing agent and amount of protein were established. During protein iodination with 125I, structural damages caused by the introduction of iodine into the protein may occur. These damages depend on the oxidizing agent used and may lead to considerable changes in the protein structure and, hence, their biological activity. Changes in secondary structure of LSZ and BSA were examined by circular dichroism (CD). Enzymatic activity tests were performed with lysozyme to check its biological activity. The Iodo Bead was found the best oxidizing agent for protein iodination.

The structure of the protein layers adsorbed at different interfaces can be determined by using neutron-reflection and small-angle neutron scattering. For highlighting the adsorbed protein layer at the interface, the technique of contrast-variation by changing the H 2 O/D 2 O ratio, is often used. For determining the scattering length density, both the protein volume in solution and the total scattering length of the protein is needed. The volume is calculated from the amino-acid sequence. For calculating the scattering length, the H/D exchange of the labile protons of the protein should be taken into account. For monitoring the H/D exchange, Positive Electrospray Ionization Mass Spectroscopy was applied. We compare experimental results for the exchange in lysozyme and β -casein with theoretical calculations. The importance of using the correct protein scattering-length density is elucidated by simultaneous model fitting to neutron reflection data at different water contrasts.

The SISAK liquid-liquid extraction system was used to extract 4.0-s 257 Rf. The 257 Rf was produced in the reaction 208 Pb( 50 Ti, 1n) 257 Rf with 237-MeV beam energy on target, separated in the Berkeley Gas-filled Separator (BGS) and transferred to a gas jet using the Recoil Transfer Chamber (RTC). The activity delivered by the gas jet was dissolved in 6-M HNO3 and Rf was extracted into 0.25-M dibutyl-phosphoric acid in toluene. This was the first time a transactinide, i.e., an element with Z ≥ 104, was extracted and unequivocally identified by the SISAK system. Thus, this pilot experiment demonstrates that the fast liquid-liquid extraction system SISAK, in combination with liquid- scintillation detectors, can be used for investigating the chemical properties of the transactinides. The extraction result is in accordance with the behaviour shown by the Rf group IV homologues Zr and Hf. and output. 2-4 During recent years, work has been undertaken to deploy SISAK in studies of the chemical properties of the transactinide elements (Z ≥ 104). 2, 5, 6 The only suitable detection method found was liquid-scintillation (LS) detection. 7 This was mainly because of the rather high flow rates (0.5-2.0 mL/s) encountered in the SISAK system. Other detection methods usually require either thin, dry samples or very thin liquid films. No suitable method was found to prepare such samples without an unac- ceptable time delay between separation and detection. LS counting has high efficiency, but suffers from relatively poor energy resolution (about 300-keV FWHM at 7-MeV α en- ergy) and is sensitive to β particles and γ rays. This puts very stringent demands on the separation system, because most of the β- and γ-emitting contaminants are produced with orders of magnitude higher yield than the transactinide under study. A huge effort was made to develop methods for LS detection of very low levels of α activity under these conditions. The most important techniques implemented are: • Pulse-shape discrimination is used to reduce the β back- ground in the α spectra by a factor >1000. Without this tech- nique the β- and γ-induced background from the surroundings and from nuclides produced in the target will interfere with the α spectrum to such an extend that it becomes useless. 8 • Real-time scintillation-yield monitoring by continuous mea- surement of the Compton edge of 662-keV 137 Cs γ rays. The position of the Compton edge is used to automatically adjust the energy calibration. Based on this adjustment the event gates used for switching the detection cells between mother and daughter mode (open or closed valve, respectively) will always be set on the correct energy range. 9

A study of the extraction of polonium from aqueous solutions containing α-hydroxyisobutyric acid (α-HIBA) was performed with four different extractants, di-n-octyl sulphide (DOS), Cyanex 272, Cyanex 301 and Cyanex 302, dissolved in toluene. The extracted complex for DOS at low α-HIBA concentrations is most likely PoO(α-HIB)2·2DOS, while at higher α-HIBA concentrations there seems to be a solvating effect implicating an extracted complex of the type PoO(α-HIB)2(α-HIBA)2·2DOS. For the extraction of polonium with Cyanex 272 the results are inconclusive. The extracted complex is either PoOA2 or PoO(α-HIB)2·2HA. For extraction with Cyanex 301 or Cyanex 302 the major extracted species does not contain any α-HIBA molecules. The neutral species in both cases is PoOA2, extracted at low extractant concentrations, while at higher extractant concentrations a complex of the type PoOA2·xHA is extracted. The extraction of polonium increases in the order Cyanex 272 < DOS < Cyanex 302 < Cyanex 301.

Subsecond 224 Pa (T1/2 = 0.85 s) was produced via the 209 Bi(18 O,3n)224 Pa reaction at the 88 inch cyclotron at the Lawrence Berkeley National Laboratory. After production it was transported via a gas-jet system to the centrifuge system SISAK 3. Following on-line extraction with trioctylamine/scintillation solutions from 1M lactic acid, 224 Pa was detected applying on-line α-liquid scintillation counting. Unambiguous identification was achieved using time-correlated α-α-decay chain analysis. This constitutes the first chemical on-line separation and detection of a subsecond α-decaying nuclide, 0.85-s 224 Pa with the fast extraction system SISAK 3.

Two simple diphosphonates, CH6P2 O6(MDP) and C2 H8 P2 O7 (HEDP),have been irradiated with neutrons to produce the corresponding 32P-labeled compounds. After irradiation for 0.5–5 hours in a thermalneutron flux of 4.2 . 1016 n . m —2 s—1 the irradiated compounds were dissolved and fractionated using a SephadexG10 column. The separated fractions were identified using planar paper chromatographyand autoradiography. The labeling yield was ca 35% for each of the compounds,and the specific activity attainable ranged up to 4.8 GBq . mol —1 . For practical applications, the labeled diphosphonates have to bepurified further.

High specific activity 27Mg was produced via recoil-aided leaching from alumina in aqueous medium during irradiation with fast neutrons from a nuclear reactor. After irradiation the aqueous medium was passed through an IC-chelate column, the 24Na formed during irradiation was removed by elution with 0.25 ml · l-1 sodium acetate and subsequently the 27Mg was eluted with 2 mol · l-1 hydrochloric acid. Irradiation of alumina with a particle size of 3 μm and a specific surface area of 100 m2 · g-1 in Milli-Q Plus Water yielded 90% of the total 27Mg activity produced. Under standard conditions activities of about 8 · 105 Bq and specific activities of ca. 1013 Bq · mol-1 were obtained at the end of irradiation. The standard working conditions involved irradiation of 200 mg alumina dispersed in 0.5 ml liquid in a fast neutron flux of 3 · 1015 m-2 · s-1 for 15 min, a waiting time of 10 min, and a processing time of 15 minutes. Various alumina samples with different particle sizes and specific surfaces were tested, and the 27Mg yields were fitted to a mathematical function. Since the high leaching yields cannot only be explained by recoil only, other phenomena such as diffusion and leaching aided by the high hydration energy of the Mg2+ ion are probably involved.

[32P]-labelled sodium monofluorophosphate (Na2FPO3) was prepared according to a procedure, which is based on melting of a mixture of carrier-added [32P]-phosphoric acid and ammonium bifluoride, both solid. Monofluorophosphate was precipitated as the silver salt from the reaction mixture, then it was converted to the sodium salt by using a cation exchange column in Na+ form. The influence of the molar ratios of the reactants, and the reaction time on the final yield was studied. Powder X-ray diffraction showed a chemical purity of about 98% and absence of NaF in the final product. After a reaction time of 2 hours and a molar ratio of the reactants of 1 : 1, the yield for the reaction was 30% of the initial 32P activity, corresponding to a specific activity of 56 MBq 32P per mmol. An increase in yield is possible by increasing the reaction time, a higher specific activity may be obtained by a decrease of carrier phosphoric acid. The advantages of the procedure developed are the availability of [32P]-phosphoric acid, and the simple preparation of the compound. Copyright © 1999 John Wiley & Sons, Ltd.

We have measured the production cross section of 1.8-s ${}^{261}\mathrm{Ha}$ from two different reactions. It was produced in the ${}^{250}\mathrm{Cf}{(}^{15}\mathrm{N},4n)$ reaction at 84 MeV and in the ${}^{243}\mathrm{Am}{(}^{22}\mathrm{Ne},4n)$ reaction at 116 MeV. Our rotating wheel system with a special parent-daughter stepping mode was used to detect \ensuremath{\alpha}-\ensuremath{\alpha} correlations between ${}^{261}\mathrm{Ha}$ and ${}^{257}\mathrm{Lr}.$ We measured 13 and 9 correlations in the two reactions, respectively. Assuming a 100% \ensuremath{\alpha} branch, we have determined the production cross section of ${}^{261}\mathrm{Ha}$ to be $0.51\ifmmode\pm\else\textpm\fi{}0.20\mathrm{nb}$ in the ${}^{250}\mathrm{Cf}{(}^{15}\mathrm{N},4n)$ reaction at 84 MeV, and $0.25\ifmmode\pm\else\textpm\fi{}0.11\mathrm{nb}$ in the ${}^{243}\mathrm{Am}{(}^{22}\mathrm{Ne},4n)$ reaction at 116 MeV. Based on the number of fission events observed in the latter reaction, we have been able to set an upper limit of 18% for the spontaneous fission branch of ${}^{261}\mathrm{Ha}.$

Fast solvent extraction is a chemical separation method, which can be applied to study exotic nuclides. Since about 1970 the SISAK technique, which is an on-line method based on multi-stage solvent extraction separations, has been successfully used to investigate the nuclear properties of β-decaying nuclides with half-lives down to about one second. During the last decade it has become possible to produce transactinide elements in high enough yields to investigate their chemical properties on a one-atom-at-a-time scale. For this purpose it was necessary to improve and change the detection part of the SISAK system in order to be capable to detect spontaneously fissioning and α-decaying nuclides in a flowing organic solution. This technique is based on liquid scintillation counting with pulse-shape discrimination and pile-up rejection

Solubility experiments and sorption studies were carried out with microcrystalline ThO 2 and alkaline cement pore waters. For fresh pore water, a solubility of 10 −9 M was found and for aged (portlandite, equilibrated) pore waters, 10 −10 M, which is expected in aqueous systems with elevated pH-values. Sorption experiments were carried out at cement to pore water ratios of 0.5 g/l, 5 g/l and 50 g/l with fresh and aged cement pore waters. With aged pore water the thorium-concentration in the aqueous solution was below the detection limit of 0.01 μg/l thorium for the experiments using 5 g/l and 50 g/l, which resulted in a lower limit for the k D -values of >48 m 3 /kg and >4.8 m 3 /kg, respectively. For the cement to pore water ratio of 0.5 g/l, the k D -value was 83.31±0.04 m 3 /kg. With fresh cement pore water the k D -values for cement to pore water ratios of 5 g/l and 50 g/l were again below the detection limit and were about one order of magnitude smaller than for aged pore waters, i.e. >3.42 m 3 /kg and >0.342 m 3 /kg, respectively, and 19.5±0.6 m 3 /kg for the cement to pore water ratio of 0.5 g/l.

The performance of the SISAK 1 liquid–liquid extraction system applied in transactinide experiments has been improved with respect to the equipment itself and the way it is operated. The improvements were checked in on-line experiments, under conditions similar to those during transactinide experiments. As a result, the yield of the separation system was increased by a factor >5. Furthermore, a cleaner organic scintillation phase was obtained due to a better phase separation. This reduced the β-background, which disturbs the α-measurements. The sensitivity of the SISAK apparatus, including the gasjet and the detection system has been improved by more than one order of magnitude.

A liquid-scintillation counting system has been developed for the internal measurement of α-particle energies and the detection of spontaneous fission events on-line in flowing organic solutions resulting from continuous rapid chemical separations by liquid-liquid extraction. The scintillator, dimethyl-POPOP and naphthalene dissolved in toluene, contains the extracting agent, di-(2-ethylhexyl-)-phosphoric acid or dibutylphosphate. An average α-energy resolution of 4,8% FWHM was measured in the energy range 4.78 to 7.69 MeV in stationary as well as flowing organic solutions. Additional features of they system are: (1) detection of spontaneous fission events by larger pulses than produced by α-particles; (2) suppression of interfering β- and γ-radiation by pulse shape discrimination and pile-up rejection; (3) identification of parent-daughter α-α- or α-fission-correlations in decay chains; (4) on-line α-energy calibration by spiking the organic phase with 3.96-s 219Rn-1.78-ms 215Po milked from a 227Ac source. In order to increase the detection efficiency, a unit with three detector cells in series was built and tested with 219Rn and 220Rn. An on-line model experiment for element 104 was carried out using the α-emitter 17-s 161Hf produced by nuclear fusion of samarium with neon and chemically separated by liquid-liquid extraction.

The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles ($6\ensuremath{\le}Z\ensuremath{\le}18$) and actinide targets suggests a disappearance of the $3n$ exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction $^{248}\mathrm{Cm}(^{26}\mathrm{Mg},xn)^{274\mathrm{\text{\ensuremath{-}}}x}\mathrm{Hs}$ and the observation of the new nuclide $^{271}\mathrm{Hs}$ produced in the $3n$ evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the $4n$ and $5n$ channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.

The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6or = Zor = 18) and actinide targets suggests a disappearance of the 3n exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction (248)Cm ((26)Mg,xn)(274-x)Hs and the observation of the new nuclide (271)Hs produced in the 3n evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4n and 5n channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.

Theoretical calculations predict $^{270}\mathrm{Hs}$ ($Z=108$, $N=162$) to be a doubly magic deformed nucleus, decaying mainly by $\ensuremath{\alpha}$-particle emission. In this work, based on a rapid chemical isolation of Hs isotopes produced in the $^{26}\mathrm{Mg}+^{248}\mathrm{Cm}$ reaction, we observed 15 genetically linked nuclear decay chains. Four chains were attributed to the new nuclide $^{270}\mathrm{Hs}$, which decays by $\ensuremath{\alpha}$-particle emission with ${Q}_{\ensuremath{\alpha}}=9.02\ifmmode\pm\else\textpm\fi{}0.03\text{ }\text{ }\mathrm{MeV}$ to $^{266}\mathrm{Sg}$ which undergoes spontaneous fission with a half-life of ${444}_{\ensuremath{-}148}^{+444}\text{ }\text{ }\mathrm{ms}$. A production cross section of about 3 pb was measured for $^{270}\mathrm{Hs}$. Thus, $^{270}\mathrm{Hs}$ is the first nucleus for which experimental nuclear decay properties have become available for comparison with theoretical predictions of the $N=162$ shell stability.

(146)Sm (T(1/2) = 10(8) y) is a long-lived radionuclide which has been produced in significant amounts during burning in a supernova (SN). Detection of this SN produced long-lived radionuclide on Earth may be helpful for getting information on nuclear synthesis at the time of our solar system's formation. Only accelerator mass spectrometry (AMS) can determine such minute traces of (146)Sm still expected in the Earth's crust. However, the villain of (146)Sm measurement through AMS is its naturally occurring stable isobar (146)Nd which is a million times more abundant than the trace amount of (146)Sm. Therefore an efficient method for the separation of samarium and neodymium is required to measure (146)Sm through AMS. A simple liquid-liquid extraction (LLX) based method for separation of samarium and neodymium has been developed using radiometric simulation. Di-(2-ethylhexyl)phosphoric acid (HDEHP) has been used as the organic reagent. A very high separation factor ( approximately 10(6)) can be achieved when a solution containing samarium and neodymium is reduced by hydroxylamine hydrochloride followed by extraction with 0.1% HDEHP diluted in cyclohexane from 0.025 M HCl solution.

Theoretical calculations predict 270Hs (Z=108, N=162) to be a doubly magic deformed nucleus, decaying mainly by alpha-particle emission. In this work, based on a rapid chemical isolation of Hs isotopes produced in the 26Mg+248Cm reaction, we observed 15 genetically linked nuclear decay chains. Four chains were attributed to the new nuclide 270Hs, which decays by alpha-particle emission with Qalpha=9.02+/-0.03 MeV to 266Sg which undergoes spontaneous fission with a half-life of 444(-148)(+444) ms. A production cross section of about 3 pb was measured for 270Hs. Thus, 270Hs is the first nucleus for which experimental nuclear decay properties have become available for comparison with theoretical predictions of the N=162 shell stability.