 Voltage measuring device |
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| Method of automatically calibrating a microprocessor controlled digital multimeter |
| It is a general object of this invention to provide an improved multimeter. It is a more specific ... |
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| Reversible thermal vest garment |
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| Electronic musical instrument |
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| Piezo electric transducer for measuring instantaneous vibration velocity |
| According to the present invention a high-sensitivity piezo electric crystal stack with interposed ... |
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| Waveform timing alignment system for digital oscilloscopes |
| An object of this invention is, therefore, to provide a system for achieving temporal alignment of ... |
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| Apparatus for generating and cooling synthesis gas |
| I claim: 1. A synthesis gas generation apparatus including a vertically extending synthesis gas ... |
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| Method and apparatus for treating waste containing organic contaminants |
| What is claimed is: 1. A countercurrent, direct fired rotary kiln for the decontamination for a ... |
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| Work-clamping unit for use in machine tools |
| OF THE INVENTION Referring to FIGS. 1 and 2, a drilling machine (M) includes a horizontal table 1 ... |
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| Method of transfer function generation and active noise cancellation in a vibrating system |
| I claim: 1. A method for the active cancellation of an incident vibration field (N(i.omega.)) ... |
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High mass ion detection system and method
| Details |
Inventors: Mahoney, John F.; Perel, Julius;
Assignee: Phrasor Scientific, Inc. (Duarte, CA)
Primary Examiner: Anderson; Bruce C.
Assistant Examiner:
Attorney, Agent or Firm: Spensley Horn Jubas & Lubitz
An improved ion detection system and method for detection of low or high mass ions. A target having a low work function, photoemissive surface layer is employed to fragment the incident ions and produce secondary negative ions and electrons. The target surface preferably is formed of a thin layer of an alkali antimonide compound, bialkali antimonide compound, multi-alkali antimonide compound, cesiated III - V semiconductor compound, or other photoemissive material having a relatively low band gap energy and electron affinity. Additionally, the photoemissive material should have a low thermionic emission level at room temperature to reduce noise levels in the detector. The secondary ions and electrons may be detected by a conventional electron multiplier detector. The potential difference between the target surface and electron multiplier detector is chosen to accelerate the secondary ions and electrons to the electron multiplier detector with an energy corresponding to high detection efficiency. |
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DETAILED DESCRIPTION What is claimed is: 1.
An ion detection system, comprising: means for providing a beam of ions; target means for intercepting said ions and ejecting secondary negatively charged particles, comprising: a target substrate having a first major surface oriented so as to intercept said ion beam; means, coupled to said target substrate, for maintaining said target substrate at a first bias potential; and a layer of photoemissive material substantially coating the first major surface of said target substrate, said photoemissive material having a band gap energy in the range of from 1-2 eV and an electron affinity of less than 1 eV; and detection means, configured with respect to said target so as to receive the secondary negatively charged particles ejected from said target means, for detecting said secondary negatively charged particles and for providing an electrical signal corresponding to said detected secondary particles.
2.
An ion detection system as set out in claim 1, wherein said photoemissive material is a bialkali antimonide compound.
3.
An ion detection system as set out in claim 1, wherein said photoemissive material is a multi-alkali antimonide compound.
4.
An ion detection system as set out in claim 3, further comprising means for providing alkali metal vapor and means for providing antimony vapor disposed adjacent said first major surface of said target substrate.
5.
An ion detection system as set out in claim 1, wherein said photoemissive material is a III - V semiconductor compound coated with a layer of cesium oxide.
6.
An ion detection system as set out in claim 1, wherein said means for providing a beam of ions comprises a source of biomolecular ions.
7.
An ion detection system as set out in claim 1, wherein said photoemissive material is an alkali antimonide compound.
8.
An ion detection system as set out in claim 1, further comprising means for cooling said target below room temperature.
9.
An ion detection system as set out in claim 1, wherein said photoemissive material has a thermionic emission of less than 10
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Audio Signal Processing 
