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A major experimental capability at Bates, especially during the last years of its operation as a National User Facility for Nuclear Physics, was the Bates Large Acceptance Spectrometer Toroid (BLAST). BLAST was designed to use the storage ring capability of the South Hall Ring along with internal gas targets, including polarized targets. The scientific program…
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Astronomical observations, such as the rotation of galaxies and their relative velocities in galaxy clusters, have provided compelling evidence that the universe contains much more matter than is visible in stars. Although this so-called “dark matter” is thought to be as much as ten times larger than the visible kind, its nature is still a…
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The purpose of the Hall D GlueX DIRC is to utilize Cherenkov radiation to provide supplemental particle identification information for charged particles reconstructed by the GlueX detector. In particular, the DIRC (Detection of Internally Reflected Cherenkov light) will enhance the ability to separate pions from kaons. The radiator for the DIRC uses four five-meter long…
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The KArlsruhe TRItium Neutrino experiment, KATRIN, will make a model-independent measurement of the mass of the electron antineutrino in the quasi-degenerate regime (m1≈m2≈m3m1≈m2≈m3). It continues a series of tritium-based experiments, including Mainz and Troitsk, which established the present model-independent limit. MIT Bates worked on two systems for this experiment, the Shield and Veto System and…
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The search for a non-zero value for the electric dipole moment of the neutron has a long history. If the neutron has an EDM it would be an explicit example of time reversal invariance violation. We know time reversal invariance is violated at a very small level in the Standard Model; this level does not…
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Historically, electron scattering from nucleons and nuclei was used to measure the size and the electric and magnetic properties of the nucleons and nuclei. It was always assumed that the scattering was mediated by the exchange of a single photon. Then, in 2000, measurements at JLab showed a significant discrepancy in the ratio of the…
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Another major and pioneering experimental effort at Bates involved the Out-Of-Plane Spectrometer (OOPS). OOPS was a special version of coincidence measurements with magnetic spectrometers. Prior to OOPS coincidence events from electron scattering were carried out with both spectrometers supported in the horizontal plane. This was the case because the problem of detecting one of the…
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New accelerator facilities (like the proposed Electron-Ion Collider) require polarized electron beam of unprecedented intensity. The eRHIC project requires average polarized electron currents on the order of 50 mA, whereas existing polarized electron sources typically operate in the 100-200 μA range and have achieved average currents of about 1 mA only with very short lifetimes.…
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The MIT Research and Engineering Center hosted a collaboration with scientists and engineers who designed a smaller and less complex proton therapy system. ProTom International markets the smaller proton therapy accelerator using the work of Russian scientist Professor Vladimir E. Balakin, who developed the technology at the Lebedev Physics Institute in Russia. The company’s compact…
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An international collaboration of scientists working at Jefferson Lab has completed a new precision measurement of parity-violating electron scattering on the proton at very low Q2 and forward angles to challenge predictions of the Standard Model and search for new physics. A unique opportunity existed to carry out the first precision measurement of the proton’s…
