119922132
Transport beam line for ultraslow monoenergetic antiprotons
A beam line for the transportation of slow antiprotons from a multiring electrode trap to an experimental chamber is described. The beam line is equipped with a three-stage differential pumping system in order to maintain a pressure lower than 1×10−12 Torr in the trap region while simultaneously having a pressure of around 1×10−6 Torr in the chamber. Tests have shown that 105 positive ions per trapping cycle were successfully extracted at 250 eV from the trap positioned in a superconducting solenoid. The ions were then further transported through three small apertures to the target area located 3.5 m downstream of the trap. Results from the first delivery of a 250 eV antiproton beam are described.
11569124
Spitzer Mid-Infrared Imaging of Nearby Ultraluminous Infrared Galaxies
We have observed 14 nearby (z < 0.16) Ultraluminous Infrared Galaxies (ULIRGs) with Spitzer at 3.6-24μm. The underlying host galaxies are well-detected, in addition to the luminous nuclear cores. While the spatial resolution of Spitzer is poor, the great sensitivity of the data reveals the underlying galaxy merger remnant, and provides the first look at off-nuclear mid-infrared activity.
2081456
Numerical solution for cosmological evolution of Newton's gravitational constant in superstring theories.
By using a computer to solve the ten-dimensional Einstein equations in superstring theories, we find that the present value for the time variation of Newton's gravitational constant is in the range of -1 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ to -6 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}12}$ ${\mathrm{yr}}^{\ensuremath{-}1}$ in the case of the flat internal potential, which confirms the previous perturbative estimate.
119232297
Subaru Constraint on Circular Polarization in I-Band Emission from the Magnetar 4U 0142+61
We present the first imaging circular polarimetry of the anomalous X-ray pulsar (AXP) 4U 0142+61 at optical wavelengths. The AXP is the only magnetar that has been well studied at optical and infrared wavelengths, and is known to have a complicated broad-band spectrum over the wavelength range. The optical polarimetric observation was carried out with the 8.2-m Subaru telescope at the I-band. From the observation, the degree of circular polarization, V, was measured to be V = 1.1 +/- 2.0%, or vertical bar V vertical bar <= 4.3% (90% confidence). The relatively large uncertainty was due to the faintness of the source (I = 23.4-24.0). Considering the currently suggested models for optical emission from magnetars, our result is not sufficiently conclusive to discriminate the models. We suggest that because linear polarization is expected to be strong in the models, linear polarimetry of this magnetar should be conducted.
124130898
Study of the neutron-rich nucleus Si-36
Excited states of N=22 Si-36, populated in deep-inelastic processes produced by the interaction of a 215 MeV beam of S-36 ions with a Pb-208 target, were studied in the present work. gamma rays from the binary fragments detected using CLARA, an array of 25 Ge Clover detectors, were measured in coincidence with projectile-like fragments detected by PRISMA, a large solid angle magnetic spectrometer. Two new gamma-ray photopeaks at energies of 1442 and 842 keV were observed and tentatively assigned to the 4(+)-> 2(+) and 6(+)-> 4(+) transitions, respectively. The systematics of the level structures of N=22 isotones are presented, and a comparison is made of the behavior of Si, Mg, and S isotopes. The level structure of Si-36 is also compared with the results of sdpf shell model calculations.
119266949
MULTIBAND STUDIES OF THE OPTICAL PERIODIC MODULATION IN THE X-RAY BINARY SAX J1808.4–3658 DURING ITS QUIESCENCE AND 2008 OUTBURST
We report on time-resolved optical imaging of the X-ray binary SAX J1808.4-3658 during its quiescent state and 2008 outburst. The binary, containing an accretion-powered millisecond pulsar, has a large sinusoidal-like modulation in its quiescent optical emission. We employ a Markov chain Monte Carlo technique to fit our multi-band light curve data in quiescence with an irradiated star model, and derive a tight constraint of 50(-5)(+6) deg on the inclination angle i of the binary system. The pulsar and its companion are constrained to have masses of 0.97(-0.22)(+0.31) M-circle dot and 0.04(-0.01)(+0.02) M-circle dot (both 1 sigma ranges), respectively. The dependence of these results on the measurements of the companion's projected radial velocity is discussed. We also find that the accretion disk had nearly constant optical fluxes over a similar to 500 day period in the quiescent state our data covered, but started brightening 1.5 months before the 2008 outburst. Variations in modulation during the outburst were detected in our four observations made 7-12 days after the start of the outburst, and a sinusoidal-like modulation with 0.2 mag amplitude changed to have a smaller amplitude of 0.1 mag. The modulation variations are discussed. We estimate the albedo of the companion during its quiescence and the outburst, which was approximately 0 and 0.8 (for isotropic emission), respectively. This large difference probably provides additional evidence that the neutron star in the binary turns on as a radio pulsar in quiescence.
8140539
Calculation of Planetary Precession with Quantum-corrected Newton ’ s Gravitation ∗
With consideration of quantization of space, we relate the Newton’s gravitation with the Second Law of thermodynamics. This leads to a correction to its original form, which takes into consideration of the role of classical measurement. Our calculation shows this corrected form of gravitation can give explanation for planetary precession. The most distinctive feature of quantum mechanics is the concept of measurement. It is more reasonable and closer to reality compared with that in classical physics. Therefore the first step that leads to a successful combination of quantum mechanics and general relativity should be the introduction of the role of measurement into classical physics. Such attempt has been scarcely seen because most physicists will not give up the concept of independent objectiveness of reality in classical physics. But as a matter of fact we can only talk about the part of the reality we are able to measure, which is certainly under the influence of our measurement. It is the purpose of this paper to show with an example that this philosophy of quantum physics may also work in classical physics. We know in both classical and quantum physics, in reality and in philosophy, nothing can be made up of zeros, otherwise many paradoxes like Zeno paradox [1] would arise. Therefore it is natural and reasonable to assume that there must be a basic measuring unit in every single measurement, which can not be measured itself. It is the basic brick that constructs the result of our measurement. I would like to call it uncertainty quantum, since we are uncertain about its nature in principle. For example, in order for the concept of length to make sense, there must be a length quantum. And time would have no meaning if there were not a time quantum. Evidently this quantum is characteristical of an observer. In this way, we have introduced a subjective feature into classical physics. We The author would like to thank Prof. Guoying Chee for beneficial discussion
124633288
Beam dynamics simulation of HEBT for the SSC-linac injector
The SSC-linac (a new injector for the Separated Sector Cyclotron) is being designed in the HIRFL (Heavy Ion Research Facility in Lanzhou) system to accelerate 238U34+ from 3.72 keV/u to 1.008 MeV/u. As a part of the SSC-linac injector, the HEBT (high energy beam transport) has been designed by using the TRACE-3D code and simulated by the 3D PIC (particle-in-cell) Track code. The total length of the HEBT is about 12 meters and a beam line of about 6 meters are shared with the exiting beam line of the HIRFL system. The simulation results show that the particles can be delivered efficiently in the HEBT and the particles at the exit of the HEBT well match the acceptance of the SSC for further acceleration. The dispersion is eliminated absolutely in the HEBT. The space-charge effect calculated by the Track code is inconspicuous. According to the simulation, more than 60 percent of the particles from the ion source can be transported into the acceptance of the SSC.
123937746
INTRINSIC LOOP REGULARIZATION AND RENORMALIZATION IN QED
We show how to regularize and renormalize the QED at the one-loop order by means of the intrinsic loop regularization method proposed by the authors. All the results are the same as those derived by means of other regularization methods.
119069538
Search for gamma-ray emission from four accreting millisecond pulsars with Fermi/LAT
We report our search for -ray emission in the energy range from 100 MeV to 300 GeV from four Accreting Millisecond Pulsars (AMPs), SAX J1808.4 3658, IGR J00291+5934, XTE J1814 338, and XTE J0929 314. The data are from four-year observations carried out by Large Area Telescope (LAT) onboard the Fermi -ray Space Telescope. The AMPs were not detected, and their -ray luminosity upper limits we obtain are 5.1 × 10 33 ergs s −1 for SAX J1808.4 3658, 2.1 × 10 33 ergs s −1 for IGR J00291+5934, 1.2 × 10 34 ergs s −1 for XTE J1814 338, and 2.2 × 10 33 ergs s −1 for XTE J0929 314. We compare our results with -ray irradiation luminosities required for producing optical modulations seen from the companions in the AMPs, which has been suggested by Takata et al. (2012), and our upper limits have excluded -ray emission as the heating source in these systems except XTE J0929 314, the upper limit of which is not deep enough. Our results also do not support the model proposed by Takata et al. (2012) that relatively strong -ray emission could arise from the outer gap of a high-mass neutron star controlled by the photon-photon pair-creation for the AMPs. Two AMPs, SAX J1808.4 3658 and IGR J00291+5934, have the measurements of their spin-down rates, and we derive the upper limits of their -ray conversion efficiencies, which are 57% and 3%, respectively. We discuss the implications to the AMP systems by comparing the efficiency upper limit values with that of 20 -ray millisecond pulsars (MSP) detected by Fermi and the newly discovered transitional MSP binary J1023+0038. Subject headings: pulsars: general – stars: neutron – binaries: close – gamma rays: stars
118630803
Particle-in-cell mode beam dynamics simulation of the low energy beam transport for the SSC-linac injector
A new SSC-linac system (injector into separated sector cyclotron) is being designed in the HIRFL (heavy ion research facility of Lanzhou). As part of SSC-Linac, the LEBT (low energy beam transport) consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC (particle-in-cell) code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ (radio frequency quadrupole) for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.