Abstract: Backgrounds of AMS measurements are reduced by eliminating unwanted charged particles which undergo charge change during the acceleration process. This reduction is accomplished by a configuration of inclined electric fields throughout the acceleration region.

Abstract: The accuracy of AMS isotopic ratio measurements is improved by a rotating slotted disk which is positioned near the focal plane of a mass recombinator which assists in injecting ions into a tandem accelerator.

Abstract: A method of detecting the amount of C-14 in a sample, comprising the following steps:ionizing the sample to form a negative-ion beam; deflecting said beam in a magnetic field and directing the deflected beam through a first acceptance aperture to remove all negative ions except mass-14 particles; accelerating said mass-14 negative ions to an energy E of the order of 10 MeV by a high voltage electrostatic field; stripping three electrons from a majority of said negative ions to form doubly-charged positive ions; deflecting said doubly-charged positive ions in an electrostatic deflecting field through 180.degree. and directing the deflected beam through a second acceptance aperture to remove particles in other than the 2.sup.

Abstract: A Rutherford backscattering analyzer comprising in combination:a hollow electrode,a voltage source for impressing upon said hollow electrode a positive voltage of the order of 10.sup.

Abstract: A dose monitoring system for ion implantation devices which employ a moving support element such as a spinning support disk which is moved through an ion beam by a scan motion uses a pick-up plate on the spinning support disk to measure incremental dose and to generate a signal which is used to vary the scan motion of the spinning support disk in order to control dosage.

Abstract: Apparatus for generating negative ions, specifically He.sup.- ions. Positive ions at a predetermined energy level from a conventional ion source are directed to a permanent magnet channel that utilizes two, spaced permanent magnet assemblies to analyze the ions and, with double focusing, to direct them to a focal point located in a lithium vapor canal. As the positive ion beam passes through a lithium vapor of constant density in a predetermined volume at the central region of the canal, electrons transfer to the ions and produce He.sup.- ions. The canal is constructed to efficiently condense and collect lithium vapor as it escapes the predetermined volume. The beam of negative ions then passes to another permanent magnet assembly that corrects any astigmatism in the emerging beam and that directs the beam, with appropriate optical properties, onto an injection axis for another accelerating structure.

Abstract: An apparatus is disclosed for the implantation of ions into semiconductor wafers wherein a plurality of storage compartments are connected through valves to a vacuum chamber. A wafer handling device transfers wafers between the storage compartments and a wafer holding device. The wafer holding device positions the wafers in front of an ion beam source. The wafer holding device is a rotatable frustum having a rear end, front end and four trapezoidally shaped sides. Clamps are provided on each side for holding the wafer against the side.

Abstract: A device for protecting electrical circuit components from surges induced by transient electromagnetic fields by isolating such components in a region of substantially uniform and constant field is disclosed. The device generally comprises at least two substantially identical conducting members in spaced, stacked relation, forming in the spaces between adjacent members a central component receiving region of substantially uniform and constant field surrounded in turn by a transitional region, a high energy storage region, and a second transitional region such that under surge conditions the device will remain electrically stable and the energy of the surge will be stored in the high energy storage region leaving the component protecting region substantially unaffected.

Abstract: The present invention comprehends an extremely sensitive apparatus which can be used for the detection of electronegative particles and provide data as to their elemental composition. A mass spectrometer selects negative ions of the required mass coming from an ion source. These ions are then directed into a dissociator which fragments complex molecules and strips electrons from the resulting products producing positively charged ions. These positively charged ions are filtered by a series of elements which independently measure some combination of the quantities: energy/charge, energy, momentum/charge, velocity, charge. Such measurement allows the actual mass of each particle to be uniquely defined and, if necessary, over-determined for reduction of backgrounds.