On the adsorption and reactivity of element 114, flerovium.

Flerovium (Fl, element 114) is the heaviest element chemically studied so far. To date, its interaction with gold was investigated in two gas-solid chromatography experiments, which reported two different types of interaction, however, each based on the level of a few registered atoms only. Whereas noble-gas-like properties were suggested from the first experiment, the second one pointed at a volatile-metal-like character. Here, we present further experimental data on adsorption studies of Fl on silicon oxide and gold surfaces, accounting for the inhomogeneous nature of the surface, as it was used in the experiment and analyzed as part of the reported studies. We confirm that Fl is highly volatile and the least reactive member of group 14. Our experimental observations suggest that Fl exhibits lower reactivity towards Au than the volatile metal Hg, but higher reactivity than the noble gas Rn.

First Study on Nihonium (Nh, Element 113) Chemistry at TASCA.

Nihonium (Nh, element 113) and flerovium (Fl, element 114) are the first superheavy elements in which the 7p shell is occupied. High volatility and inertness were predicted for Fl due to the strong relativistic stabilization of the closed 7p 1/2 sub-shell, which originates from a large spin-orbit splitting between the 7p 1/2 and 7p 3/2 orbitals. One unpaired electron in the outermost 7p 1/2 sub-shell in Nh is expected to give rise to a higher chemical reactivity. Theoretical predictions of Nh reactivity are discussed, along with results of the first experimental attempts to study Nh chemistry in the gas phase. The experimental observations verify a higher chemical reactivity of Nh atoms compared to its neighbor Fl and call for the development of advanced setups. First tests of a newly developed detection device miniCOMPACT with highly reactive Fr isotopes assure that effective chemical studies of Nh are within reach.

Study of Quasielastic Barrier Distributions as a Step towards the Synthesis of Superheavy Elements with Hot Fusion Reactions.

The excitation functions for quasielastic scattering of ^{22}Ne+^{248}Cm, ^{26}Mg+^{248}Cm, and ^{48}Ca+^{238}U are measured using a gas-filled recoil ion separator. The quasielastic barrier distributions are extracted for these systems and are compared with coupled-channel calculations. The results indicate that the barrier distribution is affected dominantly by deformation of the actinide target nuclei, but also by vibrational or rotational excitations of the projectile nuclei, as well as neutron transfer processes before capture. From a comparison between the experimental barrier distributions and the evaporation residue cross sections for Sg (Z=106), Hs (108), Cn (112), and Lv (116), it is suggested that the hot fusion reactions take advantage of a compact collision, where the projectile approaches along the short axis of a prolately deformed nucleus. A new method is proposed to estimate the optimum incident energy to synthesize unknown superheavy nuclei using the barrier distribution.

96Zr beam production for isobar experiment in relativistic heavy ion collider.

To investigate the chiral magnetic effect, 96Zr and 96Ru beams were accelerated at the relativistic heavy ion collider (RHIC) during Run-18 at Brookhaven National Laboratory. The 96Zr beam was provided from the electron beam ion source (EBIS) injector, which consists of a laser ion source, an EBIS high charge state ion breeder, a 300 keV/u radio frequency quadrupole, and a 2 MeV/u interdigital H type drift tube linear accelerator (IH-DTL). The natural abundance of 96Zr is only 2.8% with about 50% of 90Zr. To obtain a sufficient beam current, Zr material enriched to about 60% of 96Zr was used. The only available form of the enriched material was zirconium oxide (ZrO2) powder, which was not well suited for a laser ion source target. We studied and established a sintering technique of the ZrO2 powder to make a solid sample which could be installed into the laser ion source. The singly charged Zr was produced in a laser ablation plasma, extracted, and delivered to the EBIS to be ionized further to 96Zr16+. We optimized the laser irradiation condition, the EBIS confinement time, and transport through the RF linacs to maximize the performance of the injector. The total number of shots provided from the laser ion source for injection into the EBIS was 489 910. The EBIS facility provided a 192 MeV stable beam of 96Zr16+ ions to the booster ring of alternating gradient synchrotron (AGS) for further acceleration and stripping in the AGS/RHIC complex, allowing for successful data acquisition at the Solenoidal Tracker at the RHIC.

Energy of the

The low-lying isomeric state of ^{229}Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus. We determine the energy of this isomeric state by taking the absolute energy difference between the excitation energy required to populate the 29.2-keV state from the ground state and the energy emitted in its decay to the isomeric excited state. A transition-edge sensor microcalorimeter was used to measure the absolute energy of the 29.2-keV γ ray. Together with the cross-band transition energy (29.2 keV→ground) and the branching ratio of the 29.2-keV state measured in a recent study, the isomer energy was determined to be 8.30±0.92 eV. Our result is in agreement with the latest measurements based on different experimental techniques, which further confirms that the isomeric state of ^{229}Th is in the laser-accessible vacuum ultraviolet range.

Production cross sections of Mo, Nb and Zr radioisotopes from α-induced reaction on natZr.

Cross sections of α-induced reactions on natural zirconium were measured up to 50 MeV using the stacked-foil technique, activation method and high resolution γ-ray spectrometry. The production cross sections of 93m,99Mo, 90g,92m,95g,95m,96Nb and 88,89g,95Zr were determined and compared with other experimental data measured earlier and result of theoretical calculations. The integral thick target yield of 99Mo was deduced from the measured cross section data.

First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph.

The masses of ^{246}Es, ^{251}Fm, and the transfermium nuclei ^{249-252}Md and ^{254}No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of ^{246}Es and ^{249,250,252}Md were measured for the first time. Using the masses of ^{249,250}Md as anchor points for α decay chains, the masses of heavier nuclei, up to ^{261}Bh and ^{266}Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ_{2n} derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr.

Measurement of activation cross sections of alpha particle induced reactions on iridium up to an energy of 50 MeV.

Cross sections of alpha particle induced nuclear reactions on iridium were investigated using a 51.2-MeV alpha particle beam. The standard stacked-foil target technique and the activation method were applied. The activity of the reaction products was assessed without chemical separation using high resolution gamma-ray spectrometry. Excitation functions for production of gold, platinum and iridium isotopes (196m2Au, 196m,gAu, 195m,gAu, 194Au, 193 m,gAu, 192Au, 191m,gAu, 191Pt, 195mPt, 194gIr, 194mIr, 192gIr, 190gIr and 189Ir) were determined and compared with available earlier measured experimental data and results of theoretical calculations using TALYS code system. Cross section data were reported for the first time for the natIr(α,x)196m2Au, natIr(α,x)196m,gAu, natIr(α,x)191Pt, natIr(α,x)195mPt, natIr(α,x)194gIr, natIr(α,x)194mIr, natIr(α,x)190gIr and natIr(α,x)189Ir processes. A possible production route for 195mPt, the potentially important radionuclide in nuclear medicine, is discussed.

Production cross sections of 169Yb and Tm isotopes in deuteron-induced reactions on 169Tm.

The excitation functions of deuteron-induced reactions on 169Tm were measured using the stacked-foil method and high resolution gamma-ray spectrometry. The production cross sections of a medical radionuclide 169Yb were investigated. The result was compared with the previous experiments and found to be in good agreement. In addition to 169Yb, the production cross sections of Tm isotopes, 170Tm, 168Tm and 167Tm, were measured. These results were compared with the TALYS calculations taken from the TENDL-2015 online data library.

Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52MeV.

Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. The radioisotope 117mSn is a very important theranostic (therapeutic + diagnostic) radioisotope, so special care was taken to the results for that isotope. The well-established stacked foil technique followed by gamma-spectrometry with HPGe gamma spectrometers were used. The target and monitor foils in the stack were commercial high purity metal foils. From the irradiated targets 117mSn, 113Sn, 110Sn, 117m,gIn, 116mIn, 115mIn, 114mIn, 113mIn, 111In, 110m,gIn, 109mIn, 108m,gIn, 115gCd and 111mCd were identified and their excitation functions were derived. The results were compared with the data of the previous measurements from the literature and with the results of the theoretical nuclear reaction model code calculations TALYS 1.8 (TENDL-2015) and EMPIRE 3.2 (Malta). From the cross section curves thick target yields were calculated and compared with the available literature data.

A prospective study of the hypothalamic-pituitary-adrenal axis in children with acute lymphoblastic leukemia receiving chemotherapy.

BACKGROUND: Glucocorticoids are essential in protocols of therapy of acute lymphoblastic leukemia (ALL). OBJECTIVES: To assess the incidence, severity, morbidity, and risk factors of hypothalamic-pituitary-adrenal axis (HPA) suppression in children with ALL, and the time course of recovery. DESIGN: Forty standard risk ALL children treated in the Pediatric Hematology/Oncology Unit, Ain-Shams University, Egypt, were classified into dexamethasone (DXM) group: 20 patients on children cancer group protocol and prednisone (PDN) group: 20 patients on modified Berlin-Frankfurt-Muenster (BFM) study group 90 protocol. Patients were followed clinically and by laboratory assessment of morning s.ACTH, basal and after low-dose adrenocorticotrophic hormone stimulation test of cortisol and DHEAS, at diagnosis and every 2 weeks till adrenal recovery. RESULTS: HPA recovery was earlier in PDN than DXM group (P < 0.05). In induction phases 1 and 2: 65 and 75% of PDN group recovered on week 2, while 45 and 50% of DXM group recovered in week 4. Adrenal recovery was predicted 2 weeks earlier by normalized s.DHEAS. Children below 5 years of age had earlier recovery in PDN group (P = 0.04), no age effect in DXM group. CONCLUSION: Adrenal suppression is an inevitable consequence of ALL therapy. Monitoring of cortisol levels and steroid coverage during stress is recommended, and gradual steroid tapering is suggested.

Nuclear chemistry. Synthesis and detection of a seaborgium carbonyl complex.

Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product's adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)6 formulation.

Production cross sections of niobium and tantalum isotopes in proton-induced reactions on (nat)Zr and (nat)Hf up to 14 MeV.

Production cross sections of Nb and Ta isotopes in the proton-induced reactions on (nat)Zr and (nat)Hf, respectively, were measured up to 14 MeV using a stacked-foil technique. The observed nuclides in the (nat)Zr(p,x) reactions were (90g,91m,92m,95m,95g,96)Nb, (95)Zr, and (87g,88)Y. In the (nat)Hf(p,x) reactions, (175,176,177,178,179)Ta and (175)Hf were observed. The obtained cross sections for each nuclide were compared with the previously reported data and with the theoretical cross sections calculated by the TALYS-1.4 code. Thick-target yields of the observed nuclides were deduced from the measured production cross sections.

Results of RIKEN superconducting electron cyclotron resonance ion source with 28 GHz.

We measured the beam intensity of highly charged heavy ions and x-ray heat load for RIKEN superconducting electron cyclotron resonance ion source with 28 GHz microwaves under the various conditions. The beam intensity of Xe(20+) became maximum at B(min) ∼ 0.65 T, which was ∼65% of the magnetic field strength of electron cyclotron resonance (B(ECR)) for 28 GHz microwaves. We observed that the heat load of x-ray increased with decreasing gas pressure and field gradient at resonance zone. It seems that the beam intensity of highly charged heavy ions with 28 GHz is higher than that with 18 GHz at same RF power.

Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source.

A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U(35+) for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power.

Production of U beam from RIKEN 18 GHz electron cyclotron resonance ion source.

For the RIKEN radio isotope factory (RIBF) project, we produced the multicharged uranium beam with two methods. To produce lower charge state U ion beams (14+-20+) we used the UF(6) gas as an ionized gas. The typical beam intensity of U(14+-20+) was 2-1 particle microA at the extraction voltage of 14 kV. To produce higher charge state U ion beam (U(35+)), we chose the sputtering method. The beam intensity was 70 particle nA at the extraction voltage of 5.4 kV. Using this method, we successfully produced multicharged U beam continuously for one month without break for RIBF commissioning.

[Anatomy of hepatoduodenal ligament on MR imaging].

We assessed the capability of MR imaging to demonstrate the details of hepatoduodenal ligament consisting of portal vein, hepatic artery, bile duct, and lymph nodes. MR imaging was superior to CT in showing these structures, especially bile duct and lymph nodes, which is thought to result from high contrast resolution of MR imaging.