[en] An ion source test facility was constructed for making fundamental measurements of the properties of Penning ion sources. The extracted ion energies from the source can be up to 36 x q (keV), where q is the ion charge. Both negative and multiply charged positive ions were extracted from the source. The facility has high current capabilities for acceleration and for the arc power supply. These low-energy, multiply charged ions are currently being used for measurements of charge exchange cross sections, x-ray production, and electron impact excitation and ionization

[en] Experiments on mixing an easily ionized support gas with the primary ion source gas have produced large beam enhancements for high charge state light ions (masses less than or equal to 20). In the Oak Ridge Isochronous Cyclotron (ORIC), the beam increase has been a factor of 5 or greater, depending on ion species and charge state. Approximately 0.1 cc/min of the easily ionized support gas (argon, krypton, or xenon) is supplied to the ion source through a separate gas line and the primary gas flow is reduced by approximately 30 percent. The proposed mechanism for increased intensity is as follows: The heavier support gas ionizes readily to a higher charge state, providing increased cathode heating. The increased heating permits a reduction in primary gas flow (lower pressure) and the subsequent beam increase

No abstract available

[en] Quantitative estimates of charge exchange (CE) losses during acceleration are very important in the design and operation of heavy ion cyclotrons. Such estimates have been made using a vacuum model computer code which was developed to establish vacuum requirements for the MSU superconducting heavy ion cyclotron. This code uses pressure and cross-section data to calculate the radial loss of beam due to charge exchange. Since CE cross sections and radial pressure profiles are not always well known, certain specific measurements have been made using the LBL 88-Inch Cyclotron to provide experimental data needed to test the code. These include measurements of pressure versus radius under vacuum conditions closely approximating those existing during acceleration of ¹⁴N^4- and ⁴⁰Ar^8- beams. Beam intensity versus radius data demonstrating transmission losses for three beams are presented. Comparisons with theoretical predictions are given

[en] An apparatus is provided for increasing the intensities of heavy ion beams accelerated in isochronous cyclotrons at high harmonics (5th harmonic or greater) of the orbit frequency. The small intensities normally obtained at high harmonics are significantly increased by the addition of a dc ion extraction system to the cyclotron ion source. Use of the dc extraction system has increased beams of ⁴⁰Ar³⁺ on the 5th harmonic and ²⁰Ne¹⁺ on the 7th harmonic from nanoamperes to microamperes. (U.S.)

No abstract available

[en] A technique for making metal ions for cyclotrons is described. Metal and non-metal ions from solids are produced in a Penning ion source by a process that involves ions that are unable to cross the first acceleration gap between the ion source and dee and are accelerated back into the ion source where they sputter charge material into the arc. This material is ionized and extracted from the ion source and accelerated. This technique was used for a large variety of ions, both metal and non-metal, including aluminum from the metal and boron from boron nitride charge materials. The efficiency for making iron ions with different ion support gases was calculated, and these results were experimentally checked. A dual ion source is being designed for a dc Penning ion source test stand which makes an excellent source for producing ions from solids for dc extracted Penning ion sources

No abstract available

[en] The author produced a ⁷Be radioactive ion beam from the fragmentation of an accelerated heavy ion beam on the K500 superconducting heavy ion cyclotron at Michigan State University. This beam has been implanted into a ceramic disk, which is currently being used in tribology studies. This implanted ⁷Be beam has made it possible to study in situ the wear of ceramics, plastics, aluminum and other light mass materials by using extremely sensitive radioactive techniques as previously used by the surface layer activation method (10's of nm/hr sensitivity). The desired sample requirements, (1) no radiation damage, (2) no sample heating, (3) depth-dose distribution maximized at the sample surface, (4) reasonable bombardment time, (5) no interfering radiation background, can all be achieved by the ⁷Be method. The present program at MSU has focused on optimizing the heavy ion accelerator conditions for producing the ⁷Be beam. This has led to a series of experiments and calculations which clearly illustrate the unique character of ⁷Be, (it is the lightest mass radioactive species having a half live >20 days and a detectable γ-ray in the decay). The author shall report the results of the studies. The implantation of this radioactive ion beam into light mass materials opens a new area in wear studies

[en] A rotatable cold cathode Penning ion source was designed and is operating in the Oak Ridge Isochronous Cyclotron (ORIC). Previous sources for positive heavy ions were severely limited in lifetime by cathode sputtering and buildup of sputtered cathode material. The new ion source extends the cathode lifetime by a factor of approximately 6. The source cathodes are discs of tantalum, ⁷/₈ in. in diameter and ³/₈ in. thick. Upon completion of an ion source burn at one position on the circular edge of the cathode discs, each disc is rotated to an unused position for the next burn. A provision exists for continuous rotation of the cathodes. The plasma collimating holes, where the sputtered cathode tantalum is deposited, also are on discs with six possible positions. The new source resulted in increased accelerated beam currents and greater stability for heavy ions. The source was also used to produce light ion beams (H, D, α) over a wide range of intensities. (auth)