FRIB/NSCL

In 1761, the Russian polymath Mikhail Vasilievich Lomonosov (1711-1765) discovered the atmosphere of Venus during its transit over the Sun's disc. In this paper we report on experimental reenactments of Lomonosov's discovery with antique refractors during the transit of Venus June 5-6, 2012. We conclude that Lomonosov's telescope was fully adequate to the task of detecting the arc of light around Venus off the Sun's disc during ingress or egress if proper experimental techniques as described by Lomonosov in his 1761 report are employed.

The English optician John Dollond (1706-1761) performed a number of experiments with prisms of various transparent materials and concluded that an achromatic lens could exist. At that time, the dominant opinion about light refraction denied this possibility. This work presents the computer simulations of these experiments. Simulations allowed us to indicate the boundaries on an optical parameters of glasses, which could be used by J. Dollond in his prism experiments.

Analysis of the both type (flint-forward and crown-forward) achromatic doublets was carried out. The investigation revealed possible initial approximations which could be used by opticians at producing of the achromatic doublets in last half of XVIII century. The comparative analysis of approximate versions of achromatic doublets has provided additional explanation to some historical events. One more confirmation that the earliest achromatic doublets were really flint-forward type was found.

The article analysis was carried out within the confines of the replication project of the telescope, which was used by Mikhail Lomonosov at observation the transit of Venus in 1761. At that time he discovered the Venusian atmosphere. It is known that Lomonosov used Dollond 4.5 feet long achromatic telescope. The investigation revealed significant faults in the description of the approximation method, which most likely was used by J. Dollond & Son during manufacturing of the early achromatic lenses.

Analysis of the both type (flint-forward and crown-forward) achromatic doublets was carried out. The investigation revealed possible initial approximations which could be used by opticians at producing of the achromatic doublets in last half of XVIII century. The comparative analysis of approximate versions of achromatic doublets has provided additional explanation to some historical events. One more confirmation that the earliest achromatic doublets were really flint-forward type was found.

The anomalous magnetic moments of relativistic electrons and positrons have been compared by measuring the spin precession phase difference at a given time interval. The difference in the anomalous magnetic moments between the electron and the positron has been shown to lie within 1 X 10 -8 at 95% confidence level, which improves the accuracy of the previous measurements by an order of magnitude.

We report on first measurements with polarized electrons stored in a medium-energy ring and with a polarized internal target. Polarized electrons were injected at 442 MeV (653 MeV), and a partial (full) Siberian snake was employed to preserve the polarization. Longitudinal polarization at the interaction point and polarization lifetime of the stored electrons were determined with laser backscattering. Spin observables were measured for electrodisintegration of polarized 3 He, with simultaneous detection of scattered electrons, protons, neutrons, deuterons, and 3 He nuclei, over a large phase space.

The cross section of the e + e − → ωπ 0 → π 0 π 0 γ reaction was measured by the SND detector at VEPP-2M e + e − collider in the energy range from threshold up to 1.4 GeV. Results of the cross section fitting by the sum of ρ, ρ ′ and ρ ′′ contributions are presented.

Clear Cell Renal Cell Carcinoma (CC-RCC) is the most lethal of all genitourinary cancers. The functional loss of the von Hippel-Lindau (VHL) gene occurs in 90% of CC-RCC, driving cancer progression. The objective of this study was to identify chemical compounds that are synthetically lethal with VHL deficiency in CC-RCC. An annotated chemical library, the Library of Pharmacologically Active Compounds (LOPAC), was screened in parallel on VHL-deficient RCC4 cells and RCC4VHL cells with reintroduced VHL cDNA. The ROCK inhibitor, Y-27632, was identified and validated for selective targeting of VHL-deficient CC-RCC in multiple genetic backgrounds by clonogenic assays. Downregulation of ROCK1 by siRNA selectively reduced the colony forming ability of VHL-deficient CC-RCC, thus mimicking the effect of Y-27632 treatment, whereas downregulation of ROCK2 had no effect. In addition, two other ROCK inhibitors, RKI 1447 and GSK 429286, selectively targeted VHL-deficient CC-RCC. CC-RCC treatment with ROCK inhibitors is cytotoxic and cytostatic based on BrdU assay, Propidium Iodide (PI) staining, and growth curves; and blocks cell migration based on transwell assay. Importantly, knockdown of Hypoxia Inducible Factor (HIF) β in the VHL-deficient CC-RCC had a protective effect against Y-27632 treatment, mimicking VHL reintroduction. On the other hand, CC-RCCVHL cells were sensitized to Y-27632 treatment in hypoxia (2% O 2). These results suggest that synthetic lethality between ROCK inhibition and VHL deficiency is dependent on HIF activation. Moreover, HIF1α or HIF2α overexpression in CC-RCCVHL cells is sufficient to sensitize them to ROCK inhibition. Finally, Y-27632 treatment inhibited growth of subcutaneous 786-OT1 CC-RCC tumors in mice. Thus, ROCK inhibitors represent potential therapeutics for VHL-deficient CC-RCC.

VEPP-2000 electron-positron collider has been completed in the Budker INP in 2007. First beam was captured in a special lattice with switched off final focus solenoids. This regime is used for all machine subsystems test and calibration as well as vacuum chamber treatment by synchrotron radiation with electron beam current up to 150 mA. Another special low-beta lattice with solenoids switched on partially was used for the first test of the round beam option at the energy of 508 MeV. Studies of the beam-beam interaction were done in “weak-strong” and “strong-strong” regimes. Measurements of the beam sizes in both cases have indicated beam behaviour similar to expectations for the round colliding beams. Also the first collider energy calibration at the phi-meson resonance was performed with SND detector. Since the end of 2009 VEPP-2000 started first experimental work with both particle detectors SND and CMD-3 at the energies of 500-950 MeV range with the lattice mode close to project....

The Facility for Rare Isotope Beams will extend the intensity frontier of heavy ion linac facilities, with continuous beam power up to 400 kW and beam energy ≧200 MeV/u. Strict demands are placed on the beam diagnostics in the front end, linac, and beam delivery systems to ensure delivery of high quality beams to the target with minimal losses. We describe the design of diagnostic systems in each accelerator sector for commissioning and operations.

VEPP-2000 electron-positron collider construction has been completed in the Budker INP at the beginning of 2007 year. First beam was captured in a special lattice without final focus solenoids. In this regime all systems of power supplies, machine control and beam diagnostics were calibrated and tuned. In the same mode vacuum chamber treatment by synchrotron radiation was performed with electron beam current up to 150 mA. The first test of the round beam option was performed at the energy of 508 MeV with the solenoidal field 10 T in two interaction straight sections. Studies of the beam-beam interaction have been done in "weak-strong" and "strong-strong" regimes. Measurements of beam sizes in the both cases have indicated a beam behavior similar to expectations for the round colliding beams.

The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ±6 mm square. Results for these portions of the calibration are presented.

An unambiguous accordance between an objective lens for Ayscough′s telescope ′Adapted to Use at Sea′ and another compound lens which was described by William Eastland in well-known Quere during the trial in October of 1765 was revealed. Preliminary analysis of small fragments of Quere from Eastland′, Stedman′ and Champneys′ testimonies was carried.

The isomeric and β decays of the N = Z + 2 nucleus 96 Ag were investigated at NSCL. A cascade of γ-ray transitions originating from the de-excitation of a µs isomer was observed for the first time and was found in coincidence with two previously-known transitions with energies of 470 and 667 keV. The isomeric half-life was determined as 1.45 µs, more precise than previously reported. The existence of a second, longer-lived µs isomer, associated with a 743-keV γ transition, is also proposed here. Shell model results within the (p 3/2 p 1/2 f 5/2 g 9/2 ) model space, using the jj44b interaction, reproduced level energies and isomeric decay half-lives reasonably well.

In experiments at the FRS of GSI and at the SISSI-LISE3 facility of GANIL, the decay of the proton drip-line nucleus 45 Fe has been studied after projectile fragmentation of a 58 Ni primary beam. Fragment-implantation events have been correlated with radioactive decay events in silicon telescopes on an event-by-event basis. The decay-energy spectrum of 45 Fe implants shows a distinct peak consistent with a two-proton ground-state decay of 45 Fe. None of the events in the peak were found to be in coincidence with radiation or with particles which were searched for in the telescope-surrounding detectors. The decay energy for 45 Fe agrees nicely with several theoretical predictions for two-proton emission. These predictions strongly support the observed decay to be a simultaneous two-proton ground-state decay.

β-delayed proton emission from nuclides in the neighborhood of 100 Sn was studied at the National Superconducting Cyclotron Laboratory (NSCL). The nuclei were produced by fragmentation of a 120 MeV/nucleon 112 Sn primary beam on a Be target. Beam purification was provided by the A1900 Fragment Separator and the Radio Frequency Fragment Separator. The fragments of interest were identified and their decay was studied with the NSCL Beta Counting System in conjunction with the Segmented Germanium Array. The nuclei 96 Cd, 98 In g , 98 In m , and 99 In were identified as β-delayed proton emitters, with branching ratios b βp = 5.5(40)%, 5.5 +3 −2 %, 19(2)%, and 0.9(4)%, respectively. The branching ratios for 89 Ru, 91,92 Rh, 93 Pd, and 95 Ag were deduced for the first time with b βp = 3 +1.9 −1.7 %, 1.3(5)%, 1.9(1)%, 7.5(5)%, and 2.5(3)%, respectively. The b βp = 22(1)% value for 101 Sn was deduced with higher precision than previously reported. The impact of the newly measured b βp values on the composition of the type I x-ray burst ashes was studied.

The lifetimes of the yrast 8 + and 9 + states of 70 As have been measured via the γ -ray lineshape method following population by the 9 Be ( 78 Rb, 70 As) reaction at 101.6 MeV/nucleon. The strength of the E1 8 + → 7 − transition is found to be B(E1) = 1.3(5) × 10 −5 e 2 fm 2 or 1.2(4) × 10 −5 Weisskopf units (W.u.) while the 9 + → 8 + M1 transition is found to have a strength of B(M1) = 1.5(8) μ 2 N or 0.85(42) W.u. The implications for the structure of these states is discussed and found to be consistent with an assignment to a πg 9/2 νg 9/2 configuration.