Abstract:
An improved neutral particle detector (52) for an ion implantation system (10) is provided for detecting the neutral particle content of an ion beam (28) which is comprised primarily of neutral particles and positively charged ions. The neutral particle detector (52) comprises (i) a deflector plate (78) residing at a negative electrical potential; (ii) a first collecting electrode (82) residing at a positive electrical potential with respect to said deflector plate (78) for collecting secondary electrons emitted by the deflector plate (78) as a result of neutral particles in the ion beam impacting the deflector plate (78); and (iii) a second collecting electrode (84) residing at a positive electrical potential with respect to said deflector plate (78) for collecting secondary electrons emitted by the deflector plate (78) as a result of positively charged ions in the ion beam impacting the deflector plate (78). The deflector plate (78) and the collecting electrodes (82, 84) are separated by a distance through which the ion beam passes. The neutral particle detector (52) determines the neutral particle fraction of the ion beam independent of the composition or pressure of the residual background gas through which the ion beam propagates.
Abstract:
A commercially available Auger apparatus is developed in such a manner thatt is suitable for carrying out a high-resolution x-ray photoelectron spectroscopy. As a result, the stress to the material is low while the resolution capacity is high. The primary electron beam of an Auger probe impinges on the rear surface of the membrane and induces an x-ray radiation. This x-ray radiations triggers photoelectrons from the membrane surface which are used for the analysis of the uppermost atom layers of the surface. By means of a sample holder, which is designed as a Faraday cage, the electrons are kept back which are emitted from the rear surface of the membrane. The method is suitable for examining very fine structures in the .mu.- and sub-.mu.-range.
Abstract:
A method is provided for making a lithium-sodium-antimony photocathode including the step of forming a base layer including antimony on a substrate. Sodium is then deposited onto the base layer at an elevated temperature to a first peak value of responsivity, thereby forming a sodium-antimony surface. Next, at room temperature, lithium is deposited onto the substrate containing the sodium-antimony surface until the lithium-sodium-antimony photocathode develops a hazy brown color. The photocathode is sensitized by heating the substrate to an elevated temperature until a second peak value of responsivity, greater than the first peak value, is obtained. Antimony, sodium and lithium are then alternately deposited on the photocathode in order to stabilize the second responsivity peak.
Abstract:
An intrusion detection system is disclosed for safeguarding an operator of an industrial machine such as a press brake. A light screen barrier (420) comprises sequentially pulsed beams (422) which are spaced far enough apart to permit penetration by a work piece (144) without obstructing more than one beam whereas penetration by the operator's hand will obstruct at least two adjacent, successively pulsed beams. A pulse train of regularly spaced signal pulses (BRS) with each pulse corresponding to a light beam is produced when none of the light beams are obstructed. A missing pulse detector (600, 40') with a logic circuit (502) produces a control signal for stopping the machine only when two or more adjacent light beams are obstructed causing two or more successive missing pulses in the pulse train.
Abstract:
A multi-stage cylindrical mirror analyzer incorporates a primary radiation source, such as an electron gun, disposed internally and along the axis of the multi-stage analyzer. The gun includes all of the optical elements for producing a well defined beam, correcting aberration thereof and scanning the beam on a sample. The components of the gun are distributed along the axial length of the analyzer. Aberration of the scanned beam due to traversal of a subsequent lense is minimized by placing the pivot point of the deflected beam trajectory substantially at the center of the lense. The greater dispersion of the multi-stage analyzer and the unit magnification thereof permit proportionately greater exit aperture dimensions, whereby a wider field of view may be realized.
Abstract:
In a radioactive ray gauge system, a measuring head continuously detects the thickness of coated material on an advancing sheet. The head has a non-contact type sheet surface-to-head distance detector thereon. The distance detector continuously detects the distance so as to maintain the distance constant thereby eliminating error in the thickness measurement caused by sheet thickness variation, sheet-bending, warping or fluttering.
Abstract:
In a scanning electron beam system wherein a primary beam of electrons is anned over the surface of a specimen and electron images are generated by collecting electrons scattered from the surface, an improved electron collector for selectively collecting the primary electrons that have suffered low loss in being scattered by the surface. Three symmetrically shaped mesh grids are arranged in front of a scintillator in the path of the backscattered electrons. The grids are disposed relative to each other and biased so that the electric fields permit passage of electrons within a narrow energy range. The scintillator is coated with a layer of tantalum and a layer of gold to provide thermal stability and resistance to damage from bombardment by high-energy electrons.