Cyclotron emission

In the 15 keV - 10 MeV region, line-forming processes such as nuclear excitation, radioactivity, positron annihilation, cyclotron emission and absorption become important, and when used as astrophysical tools, are almost certain to lead to fundamental new discoveries. Unique astrophysical information is contained in the spectral shift, line width, and line profiles. Detailed studies of these processes require the resolving power (E/AE = 500) of a Germanium spectrometer such as that employed on INTEGRAL. Lower resolution spectrometers (e.g. SIGMA, OSSE, COMPTEL) do not have sufficient energy resolution to study the parameters of these lines. The... 

Most of the emissions were polarized and probably due to maser-cyclotron emission. The emissions range in frequency from about 20 kHz to 800 kHz, well below the frequency range that is observable from the Earth. The emissions suggest a magnetosphere rich in magnetohy-drodynamic phenomena. 

The sources used in Ni Mossbauer work mainly contain Co as the parent nuclide of Ni in a few cases, Cu sources have also been used. Although the half-life of Co is relatively short (99 m), this nuclide is much superior to Cu because it decays via P emission directly to the 67.4 keV Mossbauer level (Fig. 7.2) whereas Cu ti/2 = 3.32 h) decays in a complex way with only about 2.4% populating the 67.4 keV level. There are a number of nuclear reactions leading to Co [4] the most popular ones are Ni(y, p) Co with the bremsstrahlung (about 100 MeV) from an electron accelerator, or Ni(p, a) Co via proton irradiation of Ni in a cyclotron. 

Principles and Characteristics Particle-induced X-ray emission spectrometry (PIXE) is a high-energy ion beam analysis technique, which is often considered as a complement to XRF. PIXE analysis is typically carried out with a proton beam (proton-induced X-ray emission) and requires nuclear physics facilities such as a Van der Graaff accelerator, or otherwise a small electrostatic particle accelerator. As the highest sensitivity is obtained at rather low proton energies (2-4 MeV), recently, small and relatively inexpensive tandem accelerators have been developed for PIXE applications, which are commercially available. Compact cyclotrons are also often used. 

HPSE liquid chromatography High-pressure solvent extraction ICR emission spectrometry Ion-cyclotron resonance... 

Inductively Coupled Plasma Mass Spectrometry Inductively Coupled Plasma Optical Emission Spectrometry Ion Cyclotron Resonance Ion Diffraction... 

Cyclotrons and accelerators are sources of charged particles (i.e., protons, deuterons, a particles, etc.), and the radionuclides produced are generally proton rich and decay by positron emission and/or electron capture. A positive ion beam is eventually extracted from the cyclotron, regardless of whether positive or negative ions were accelerated. The isotope of interest is separated from the target for use in chemical syntheses. Accelerator- or cyclotron-produced radioisotopes tend to be the most expensive as only one radionuclide is produced at a time. 

Being related to a resonant behavior of the opacity for the extraordinary mode, the proton cyclotron line appears as an absorption feature in the spectrum. Atmospheres comprised of heavy elements (Fe) were studied by Rajagopal et al. (1997) the emergent spectra exhibit a variety of emission/absorption features produced by atomic transitions. Such models, however, suffer from our lack of knowledge of the ionization states and opacities of metals in a strong magnetic field. 

Ultra short lived radionuclides, with a half-life of a few seconds to a few minutes are readily available from long-lived parent radionuclides adsorbed to an organic or inorganic ion exchange support matrix (1-3). These radionuclide generator systems are an inexpensive alternative to an on-site cyclotron, especially for positron emitters used for positron emission tomography (PET). 

Automated radionuclide generators capable of providing precise dose delivery of multi-millicurie amounts of short-lived positron emitters on demand from a safe and easily operated system are an attractive alternative to on-site cyclotrons for positron emission tomography. The availability of curie quantities of parent radionuclides from national laboratories and the development of microprocessor automation makes it feasible to utilize these generators in the clinical setting. 

Sr was more stable in vivo but Ag was more lipophilic. These results suggest that generator-produced isotopes such as Rb-82 (T% = 75 sec) sequestered inside cryptands may be useful freely diffusible tracers for measuring blood flow by positron emission tomography. It would be more convenient to make this measurement with generator-produced isotopes than with water from cyclotron-produced oxygen-15 (Th = 122 sec). 

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