K + scattering from nuclei Hungerford, Ed V.
Nuclear physics. A,
03/1995, Letnik:
585, Številka:
1
Journal Article
Recenzirano
The present status of the K
+-nuclear scattering problem is discussed, and implications of the new data sets involving K
+ total, elastic, and quasi-free cross sections are pointed out.
An experiment with a newly developed high-resolution kaon spectrometer and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab. The ground state of a ...neutron-rich hypernucleus, (Λ)(7)He, was observed for the first time with the (e, e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The (Λ)(7)He binding energy supplies the last missing information of the A = 7, T = 1 hypernuclear isotriplet, providing a new input for the charge symmetry breaking effect of the ΛN potential.
Architecture of the MEGA detector trigger Chen, Y.K.; Cooper, M.D.; Cooper, P.S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/1996, Letnik:
372, Številka:
1
Journal Article
Recenzirano
The trigger for the MEGA detector system is based on signals from single, high-energy photons interacting in one of the three MEGA pair spectrometers. The trigger is divided into a fast and a slow ...stage. The first stage produces a fast output if a specific pattern of detector hits is observed in the scintillators and high-speed wire chambers of a pair spectrometer. The second, slow-stage interrogates drift chamber hit patterns and provides a veto when the pattern fails a minimal requirement for reconstruction of the hits into a pair of circular orbits. The trigger interacts with the photon detector electronics by gating limited sections of the detector during the read-out of an event. This paper describes the two stage trigger system, the photon detector electronics, and the implementation of the trigger outputs to strobe the data acquisition system. The performance of the trigger is compared to Monte Carlo simulations of the photon detector response.
The results of experiment E906, undertaken at the Alternating Gradient Synchrotron of the Brookhaven National Laboratory (BNL-AGS), were reanalyzed to clarify the signature of the decays of the ...double- and single-{lambda} hypernuclei that could have been produced in this experiment. This reanalysis indicates that instead of the reported decay of {sub {lambda}}{sub {lambda}}{sup 4}H through a proposed resonance in {sub {lambda}}{sup 4}He, it is more probable that the decay of the {sub {lambda}}{sub {lambda}}{sup 7}He hypernucleus was observed. This decay was accompanied by a background of coincident decays of pairs of the single hypernuclear fragments {sub {lambda}}{sup 3}H with {sub {lambda}}{sup 4}H, {sub {lambda}}{sup 3}H with {sub {lambda}}{sup 3}H, and {sub {lambda}}{sup 4}H with {sub {lambda}}{sup 4}H. An attempt was also made to determine if any other double or coincident single hypernuclear species could be observed in the data.
The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 (June 1998) in a 51.7° orbit at altitudes between 320 and.A search for antihelium nuclei in the ...rigidity range 1–was performed. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of <1.1×10−6 was obtained.The high energy proton, electron, positron, helium, antiproton and deuterium spectra were accurately measured.For each particle and nuclei two distinct spectra were observed: a higher energy spectrum and a substantial second spectrum. Positrons in the second spectrum were found to be much more abundant than electrons. Tracing particles from the second spectra shows that most of them travel for an extended period of time in the geomagnetic field, and that the positive particles (p and e+) and negative ones (e−) originate from two complementary geographic regions. The second helium spectrum flux over the energy range 0.1–was measured to be . Over 90 percent of the helium flux was determined to be at the 90% confidence level. (Elsevier)
Construction of the MEGA photon detector
Nuclear instruments and methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment/Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/1994
Journal Article
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