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US 4,054,810 AGranted
Field emission ion source having heated anode
AssigneeVarian Mat GmbH
InventorHans-Dieter Beckey
Life of this patent
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Abstract
A field emission ion source of the type employing a thin anode having an elongated surface utilizes local heating of the anode to prevent material from being adsorbed on the anode's surface. The anode may be a wire or a thin knife-edged metal strip through which an electrical current is passed to heat the anode.
Claims3
A method of obtaining low fragment ion yield from a field emission ion source of the type having
- a. an evacuated ionization chamber,
- b. a cathode
- c. an anode having a thin elongated surface facing the cathode, and
- d. focussing means for forming an ion beam, the method including the steps of
- 1. placing the anode at a high electric potential relative to the cathode to create an intense electric field in the ionization chamber,
- 2. introducing a vaporous or gaseous sample into the ionization chamber, and
- 3. locally heating the anode to prevent condensation of the sample on the anode's thin elongated surface during the production of ions by field emission.
4 more elements
In a field emission ion source for ionizing gaseous or vaporous samples where the apparatus is of the type having
- a. an evacuated ionization chamber for containing the sample,
- b. a cathode,
- c. an anode having a thin elongated surface facing the cathode, and
- d. means for establishing an electric field between the anode and cathode of sufficient intensity to cause ionization of the sample by field emission,
- the improvement of
- means for locally heating the anode to a temperature which prevents condensation of the sample on the anode's thin elongated surface during the production of ions by field emission.
3 more elements
Dependencies are inferred from the claim text.