Cold Cathode Field Emission X-Ray Tube

(for Flash Radiography)

 

 

 

8(20cms) long, 1(2.5cms) diameter.

Unknown make.

2nd half, 20th Century.

Unknown specifications.

 

 

 

Emission of electrons from cold cathodes consisting of one or more sharp needle points, the so-called field emission, has been known for many years. In the fifties or early sixties it has been demonstrated that x-ray tubes with field emission cathodes, obviously remarkably simple in construction compared to those with hot filament cathodes, could be made to generate x-ray beams of very high intensities with output currents of hundreds of Amperes as a series of pulses controlled by suitably designed highly efficient pulsers, particularly useful in flash radiography and stop motion pictures of high speed events.

 

Hereafter, specifications of the Fexitron 542 tube (apparently similar in size, structure and shape to the above tube), made by the Field Emission Corporation, McMinniville, Oregon :

 

Pulse duration

Applied voltage

Maximum current at maximum voltage

Peak power

X-Ray source diameter

Anode material

 

0.03

75-105

1400

147

1.5

Tungsten

 

Microseconds

kV

Amperes

Megawatts

Millimeters

 

 

(George L. Clark, The Encyclopedia of X-Rays and Gamma Rays, p.1097,

Reinhold Publishing Corporation, NewYork, 1963)



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