Photodetachment of negative ions using a continuously tunable laser and an ion cyclotron resonance spectrometer
Negative ions photodetachment by continuously tunable laser and ion cyclotron resonance spectrometer
Brauman, J. I.↗
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Saturation effects in cyclotron resonance oscillators
Large signal saturation effects in cyclotron resonance oscillators, using helical electron beam-cavity interaction model
Rowe, J. F., Jr.↗
Comprehensive theory for ion cyclotron resonance power absorption - Application to line shapes for reactive and nonreactive ions
Ion cyclotron resonance power absorption theory application to reactive and nonreactive ions line shapes, using Wobschall-Graham-Malone phenomenological equation of motion
Comisarow, M. B.↗
Ion cyclotron resonance spectroscopy
Ion cyclotron resonance spectroscopy, discussing fundamentals, instrumentation and ion-molecule chemistry applications
Baldeschwieler, J. D.↗
Ion cyclotron resonance power absorption - Collision frequencies for CO2/plus/, N2/plus/, and H3/plus/ ions in their parent gases
Ion cyclotron resonance power absorption, deriving expression for average ion kinetic energy at saturation in steady state limit
Huntress, W. T., Jr.↗
Magnetic drift waves near proton cyclotron frequency
Magnetic drift waves near proton cyclotron frequency, noting magnetic field gradient role in plasma instability
Wu, C. S.↗
Cyclotron production of I-123: An evaluation of the nuclear reactions which produce this isotope
The reactions studied which produce I-123 directly were Sb-121(He-4,2n) I-123, Sb-121(He-3,n) I-123, Te-122(d,n) I-123, Te-122(He-4,p2n) I-123, Te-122(He-3,pn) I-123, and Te-123(He-3,p2n) I-123. Reactions which produce I-123 indirectly through the positron decay of 2.1-hour Xe-123 were Te-122(He-4,3n) Xe-123, Te-122(He-3,2n) Xe-123 and Te-123(He-3,3n) Xe-123. Use of the gas flow I-123 cyclotron target assembly is recommended for the production of I-123 with radiochemical purity greater than 99.995%.
Sodd, V. J.↗
Cyclotron production of I-123: An evaluation of the nuclear reactions which produce this isotope
The use of the various nuclear reactions is described by which I-123,a low radiation dose radiopharmaceutical, can be cyclotron-produced. Methods of directly producing I-123 and those which indirectly produce the radionuclide through the beta (+) decay of its nautral precursor, Xe-123. It is impossible to separate from the radioiodine contaminants, notably I-124, which occur in the direct method. Thus, it is preferable to produce pure I-123 from Xe-123 which is easily separated from the radioiodines. Among the characteristics of I-123 is the capability of reducing the patient dose in a thyroid uptake measurement to a very small percentage of that delivered by the more commonly used I-131.
Sodd, V. J.↗
Operating features of an ion-cyclotron-wave plasma apparatus running in the RF-sustained mode
An experimental study has been made of an ion-cyclotron-wave apparatus operated in the RF-sustained mode. This is a mode in which the Stix RF coil both propagates the waves and maintains the plasma. Problems associated with this method of operation are presented. Some factors that are important to the coupling of RF power are noted. In general, the wave-propagation and wave-damping data agree with theory. Some irregularities in wave fields are observed. Maximum ion temperature is 870 eV at a density of 5 times 10 to the 12th power per cubic centimeter and RF power of 90 kW. Coupling efficiency is 70 percent.
Swett, C. C.↗
Theory and simulation of the beam cyclotron instability.
A theory of plasma beam cyclotron instability is developed on the basis of computer simulation experiments. The theory holds that at certain turbulence levels, electron cross-field diffusion which supresses the electron gyroresonances is created by turbulent wave-particle interactions in a plasma beam after a period of quasi-linear exponential development of turbulence. The stabilizing effect of Landau ion damping is noted. The behavior of cold and hot ions is discussed.
Lampe, M.↗
Cyclotron drift instability in the bow shock.
It is argued that the cyclotron drift instability (coupled ion waves and electron Bernstein modes) can explain many structural features of the weak electrostatic turbulence observed in bow shock magnetic-field gradients and thus that it provides a more attractive speculation than the ion acoustic or Buneman instabilities previously suggested as weak turbulence sources.
Wu, C. S.↗
Magnetic-field measurements for the Lewis Research Center cyclotron
The magnetic field of the Lewis Center cyclotron was mapped by using a Hall-effect magnetic-field transducer. Main-field Fourier coefficients were determined on a polar mesh of 40 radii for each of seven levels of main-field coil current. Incremental fields for eight sets of trim coils and two sets of harmonic coils were also determined at four of these main-field levels. A stored-program, digital computer was used to perform the measurements. The process was entirely automatic; all data-taking and data-reduction activities were specified by the computer programs. A new method for temperature compensation of a Hall element was used. This method required no temperature control of the element. Measurements of the Hall voltage and Hall-element resistance were sufficient to correct for temperature effects.
Fessler, T. E.↗
Performance of an ion-cyclotron-wave plasma apparatus operated in the radiofrequency sustained mode
An experimental study has been made of an ion-cyclotron-wave apparatus operated in the RF-sustained mode, that is, a mode in which the Stix RF coil both propagates the waves and maintains the plasma. Problems associated with this method of operation are presented. Some factors that are important to the coupling of RF power are noted. In general, the wave propagation and wave damping data agree with theory. Some irregularities in wave fields are observed. Maximum ion temperature is 870 eV at a density of five times 10 to the 12th power cu cm and RF power of 90 kW. Coupling efficiency is 70 percent.
Swett, C. C.↗
Cyclotron side band emissions from magnetospheric electrons
Very low frequency emissions with subharmonic cyclotron frequency from magnetospheric electrons were detected by the S(3)-A satellite (Explorer 45) whose orbit is close to the magnetic equatorial plane where the wave-particle interaction is most efficient. These emissions were observed during the main phase of a geomagnetic storm in the nightside of the magnetosphere outside of the plasmasphere. During the event of these side-band emissions, the pitch angle distributions of high energy electrons (greater than 50 keV) and of energetic protons (greater than 100 keV) showed remarkable changes with time, whereas those of low energy electrons and protons remained approximately isotropic. In this type of event, emissions consist essentially of two bands, the one below the equatorial electron gyrofrequency, and the other above. The emissions below are whistler mode, and the emissions above are electrostatic mode.
Maeda, K.↗
Evidence that the electrostatic ion cyclotron instability is saturated by ion heating
Observations have been made of electric field oscillations near the local ion gyro frequency and of an intense beam of plasma ions at the edge of an auroral arc. The observations are in good agreement with ion heating as the saturation mechanism for electrostatic ion cyclotron waves.
Kelley, M. C.↗
Positron emission reconstruction tomography for the assessment of regional myocardial metabolism by the administration of substrates labeled with cyclotron produced radionuclides
A positron emission transverse tomograph device was developed which provides transaxial sectional images of the distribution of positron-emitting radionuclides in the heart. The images provide a quantitative three-dimensional map of the distribution of activity unencumbered by the superimposition of activity originating from regions overlying and underlying the plane of interest. PETT is used primarily with the cyclotron-produced radionuclides oxygen-15, nitrogen-13 and carbon-11. Because of the participation of these atoms in metabolism, they can be used to label metabolic substrates and intermediary molecules incorporated in myocardial metabolism.
Ter-Pogossian, M. M.↗
A preliminary area survey of neutron radiation levels associated with the NASA variable energy cyclotron horizontal neutron delivery system
The 25 MeV deuteron beam from the NASA variable energy cyclotron incident on a thick beryllium target will deliver a tissue neutron dose rate of 2.14 rad micron A-min at a source to skin distance of 125 cm. A neutron survey of the existing hallways with various shielding configurations made during operating of the horizontal neutron delivery system indicates that minimal amounts of additional neutron shielding material are required to provide a low level radiation environment within a self-contained neutron therapy control station. Measurements also indicate that the primary neutron distribution delivered by a planned vertical delivery system will be minimally perturbed by neutrons backscattered from the floor.
Roberts, W. K.↗
Ion cyclotron resonance studies of some reactions of C/+/ ions
Product distributions and rate constants for the reaction of ground state C(+) ions with O2, NO, HCl, CO2, H2S, H2O, HCN, NH3, CH4, H2CO, CH3OH, and CH3NH2 have been measured. Rate constants were obtained using ion cyclotron resonance trapped ion methods, and product distributions were obtained using a tandem mass spectrometer. Rapid carbon isotope exchange has also been observed in C(+)-CO collisions.
Anicich, V. G.↗