401 research outputs found

    SMM detection of interstellar Al-26 gamma radiation

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    The gamma ray spectrometer on the Solar Maximum Mission Satellite has detected the interstellar Al-26 line when the Galactic center traversed its aperture. The center of the emission is consistent with the location of the Galactic center, but the spatial distribution is presently not well defined. The total flux in the direction of the Galactic center is 4.3 + or - 0.4) x .0001 gamma/sq cm-s-rad for an assumed population I distribution

    A gamma ray monitor for the OSO-7 spacecraft

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    A 3 in. x 3 in. NaI(Tl) gamma ray (0.3 to 10 MeV) spectrometer with a CsI(Na) charged particle and anti-Compton shield has been developed for the Orbiting Solar Observatory (OSO-7) which was launched September 30, 1971. The instrument, designed for a rotating wheel compartment, utilizes a 377 channel quadratic PHA with accumulation times of 3, 1, or 0.5 minutes. Quick look and calibration data obtained via a direct data link to a minicomputer allows near real time monitoring and control of the experiment. Various commands changing the operating mode can be executed. The functions which can be commanded include: rotation of the quadrants in which data is collected by 90 deg; gain adjustment of the central detector over a 6:1 range; manual or automatic sequencing of calibrations; variations of accumulation times by telemetering selected channels; and selection of reference directions. A small X-ray detector covering the range 7.5 to 120 keV is also included

    Search for gamma ray lines from SS433

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    Data obtained with the Gamma Ray Spectrometer (0.3 to 9 MeV) aboard the Solar Maximum Mission satellite from 1980 to 1985 for evidence of the reported Doppler shifted lines from SS433 were examined. The data base covers a total of 468 days when SS433 was in the field of view and includes times of quiescent and flaring radio activity. In 9 day integrations of the SMM data no evidence is found for gamma ray line emission from SS433. The 99% confidence upper limits for 9 day integrations of the shifted 1.37 and 6.1 MeV lines are 0.0013 gamma/sq cm-s and 0.0007 gamma/sq cm-s, respectively. The 360 day time averaged upper limits are 0.0002 gamma/sq cm-s x 0.0001 gamma/sq cm-s for both lines

    The search for a permanent electric dipole moment using 129Xe and 3He

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    Time reversal and parity non‐invariant interactions within an atom naturally give rise to an atomic permanent electric dipole moment (PEDM). For noble gas atoms, the size of such a PEDM scales as Z2 and higher powers of Z depending on the actual manifestation of T non‐invariance, most importantly a distribution of electric dipole moment within the nucleus (Schiff Moment) and a T‐odd tensor interaction between the nucleus and atomic electrons. We have developed techniques to simultaneously measure the PEDMs of 129Xe and 3He in a single cell in order to mitigate systematic effects due to leakage currents and common mode problems such as magnetic field and time base noise. The philosophy of our approach is that PEDM of 3He is negligible compared to that of 129Xe and thus we use the 3He as a ‘‘magnetometer’’ and monitor of systematic effects. Sensitivity of ≊10−25 e‐cm per day has been demonstrated in preliminary work using a free‐induction decay technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87703/2/73_1.pd

    The search for a permanent electric dipole moment using 129Xe and 3He

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    Time reversal and parity non‐invariant interactions within an atom naturally give rise to an atomic permanent electric dipole moment (PEDM). For noble gas atoms, the size of such a PEDM scales as Z2 and higher powers of Z depending on the actual manifestation of T non‐invariance, most importantly a distribution of electric dipole moment within the nucleus (Schiff Moment) and a T‐odd tensor interaction between the nucleus and atomic electrons. We have developed techniques to simultaneously measure the PEDMs of 129Xe and 3He in a single cell in order to mitigate systematic effects due to leakage currents and common mode problems such as magnetic field and time base noise. The philosophy of our approach is that the PEDM of 3He is negligible compared to that of 129Xe and thus we use the 3He as a ‘‘magnetometer’’ and monitor of systematic effects. Sensitivity of ≊10−25 e‐cm per day has been demonstrated in preliminary work using a free induction decay technique.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87730/2/84_1.pd

    Monte Carlo calibration of the SMM gamma ray spectrometer for high energy gamma rays and neutrons

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    The Gamma Ray Spectrometer (GRS) on the Solar Maximum Mission spacecraft was primarily designed and calibrated for nuclear gamma ray line measurements, but also has a high energy mode which allows the detection of gamma rays at energies above 10 MeV and solar neutrons above 20 MeV. The GRS response has been extrapolated until now for high energy gamma rays from an early design study employing Monte Carlo calculations. The response to 50 to 600 MeV solar neutrons was estimated from a simple model which did not consider secondary charged particles escaping into the veto shields. In view of numerous detections by the GRS of solar flares emitting high energy gamma rays, including at least two emitting directly detectable neutrons, the calibration of the high energy mode in the flight model has been recalculated by the use of more sophisticated Monte Carlo computer codes. New results presented show that the GRS response to gamma rays above 20 MeV and to neutrons above 100 MeV is significantly lower than the earlier estimates

    Particle acceleration

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    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV

    On linearity of separating multi-particle differential Schr\"odinger operators for identical particles

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    We show that hierarchies of differential Schroedinger operators for identical particles which are separating for the usual (anti-)symmetric tensor product, are necessarily linear, and offer some speculations on the source of quantum linearity.Comment: As accepted by Journal of Mathematical Physics. Original title "Separating multi-particle differential Schroedinger operators for identical particles are necessarily linear". Some new discussion and references. Main result unchanged. Uses RevTeX 4, 9 page

    Two-Bit Gates are Universal for Quantum Computation

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    A proof is given, which relies on the commutator algebra of the unitary Lie groups, that quantum gates operating on just two bits at a time are sufficient to construct a general quantum circuit. The best previous result had shown the universality of three-bit gates, by analogy to the universality of the Toffoli three-bit gate of classical reversible computing. Two-bit quantum gates may be implemented by magnetic resonance operations applied to a pair of electronic or nuclear spins. A ``gearbox quantum computer'' proposed here, based on the principles of atomic force microscopy, would permit the operation of such two-bit gates in a physical system with very long phase breaking (i.e., quantum phase coherence) times. Simpler versions of the gearbox computer could be used to do experiments on Einstein-Podolsky-Rosen states and related entangled quantum states.Comment: 21 pages, REVTeX 3.0, two .ps figures available from author upon reques
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