English Electric Valve Company Limited

Eev Limited

The Secretary of State for Defence in Her Britannic Majesty's Government

Arthur Maitland

Hugh Menown

Clifford R Weatherup

Ian A Strudwick

Ewan S Livingstone

Christopher V Neale

Graeme L Clark

Herbert A French

Timothy P Donaldson

Andrew P Shaw

William Dawber

Brian P Condon

Colin J Flynn

Colin A Pirrie

Robert J Carman

Wide bandwidth RF spectrum analyser

Laser apparatus

Metal vapor laser apparatus includes an envelope within which is contained electrodes and a plurality of cylindrical copper segments arranged between them. During operation of the laser, bromine and helium buffer gas are arranged to flow through the envelope, causing copper bromide to be produced. When a discharge is established between the electrodes, the copper bromide vaporizes and dissociates to give copper vapor which is then excited to produce a population inversion. Such apparatus is able to operate at relatively low temperatures, in the region of 600.degree. C.

Metal vapor laser apparatus

Laser apparatus includes a gas filled tube and is arranged to act as a switch to trigger, within the tube itself, a discharge. The power dissipated in the discharge is applied to material which forms, or is to form, a laser amplifying medium, to provide pumping power. Thus, no external switch, such as a thyratron, is required, unlike conventional laser arrangements.

Laser apparatus having a discharge triggering device inside a laser tube

Laser apparatus including a relatively long cylindrical cathode within a discharge tube containing a buffer gas at a low pressure of less than 1 Torr. By employing a laser constructed according to the invention, it is possible to achieve a plasma which extends along the length of the cathode, which may be up to one meter long.

Gas laser apparatus having a low pressure buffer gas

Laser apparatus includes hydrogen or deuterium buffer gas and dispenser reservoirs which contain a hydride or deuteride as appropriate. As gas molecules from the buffer gas are lost within the discharge tube due to trapping and sputtering processes, hydrogen or deuterium is given off from the surfaces of the reservoirs at a greater rate to maintain the vapor pressure within the discharge tube at a substantially constant level. Thus the laser apparatus may operate in a 'sealed-off' mode, that is without requiring that buffer gas be flowed through it.

In a laser arrangement, solid or liquid material, at least part of which comprises a laser amplifying medium, is atomized in a gas prior to being applied to a discharge region. In one embodiment of the invention, the gas is combustible and is ignited to produce a flame which provides heating of the material. The invention is particularly applicable to metal vapour lasers. In another embodiment of the invention, the material is atomized in an inert gas and a discharge within a laser discharge tube is used to provide excitation.

Metal vapor laser with improved laser medium formation

A discharge tube arrangement, for example, a thyratron, in accordance with the invention has a first electrode arranged co-axially about a second electrode. Thus, in a thyratron, the anode may surround the cathode or vice versa. The envelope may be tubular having an aperture at its center. The discharge tube arrangement is constructed such that it is capable of being added to another such arrangement. A plurality of such arrangements may be added together to produce, for example, a thyratron capable of large current conduction.

Discharge tubes

Laser apparatus includes an outer envelope which contains a plurality of laser discharge tubes. Each of the laser discharge tubes includes copper pieces which, when vaporised, acts as a laser amplifying medium. Each of the laser discharge tubes is of the maximum volume compatible with good efficiency which, when combined with the output power of the other tubes, enables a very high power output to be achieved compared with previously known tubes.

A laser arrangement includes electron beam apparatus comprising a plurality of electrodes, each of which having an aperture therethrough. The apertures are aligned along the longitudinal axis of an envelope which surrounds them and contains gas. The electrodes are electrically connected such that, of an adjacent pair, one is at a lower potential than the other. An electron beam is produced between the first electrode and an adjacent electrode, and is accelerated along the axis through the apertures, the electron current increasing in magnitude. The electron beam produced is used to provide pumping powder to the gas contained within the envelope such that it acts as a laser amplifying medium.

Electron beam apparatus

Apparatus for forming an electron beam sheet includes a cathode member having a slot in a front surface thereof, a grid electrode and the anode of a thyratron. When it is desired to trigger the thyratron into conduction, a suitably large potential difference is applied between the cathode member and the grid, resulting in an electron beam sheet being produced extensive of a slot formed in the front surface of the cathode member. This produces ionisation and a main discharge current is established between the main anode and cathode of the thyratron.

Apparatus for forming an electron beam sheet

Laser apparatus includes a ceramic tube within which is contained a gas and a cylindrical cathode having a plurality of holes therethrough. An anode is located along the axis of the tube. During operation of the apparatus, a large potential difference is applied between the anode and cathode, causing a plurality of electron beams to be formed extensive of the holes. Vapor is emitted from the electron bombarded cylindrical rod and becomes excited, and laser action occurs.

Laser apparatus having cathode bore directing electron beam onto anode

Discharge tube apparatus includes an outer containing vessel and a structure comprising for example five metal cylinders located co-axially within it. Each of the metal cylinders includes projecting spacers on its outer surface which serve to space it from adjacent ones. Such a structure is thermally insulating and may be arranged to enable a large temperature difference to be maintained between the interior of the discharge tube and the outer containing vessel. In other embodiments, a plurality of structures are included disposed along the axis of the tube. Also, dispenser segments for dispensing part of the active medium of a metal vapor laser may be included and arranged to shield vulnerable surfaces in the tube from direct exposure to the discharge.

Discharge tube apparatus

A metal vapor discharge tube includes cylindrical dispenser blocks of sintered tungsten which are porous and support metal whose vapor is to form at least part of the active medium of the tube. Thus, the dispenser blocks retain the metal, holding it in position when in its solid and liquid states. Heat shields serve to retain heat within the envelope of the discharge tube and uniformly heat the cylinders.

Laser apparatus comprising a discharge vessel of thermally insulating material and a protective metal layer disposed on the inner surface of the discharge vessel. During operation of the laser apparatus, copper powder is vaporised to form at least part of the laser active medium. Because of the protective metal layer the discharge vessel wall is prevented from damage due to its contents.

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St. Andrews, United Kingdom

Arthur Maitland