Cold electron number amplifier

An x-ray tube comprising:

• a) an evacuated enclosure having an internal pressure of less than 10−6 atm;
• b) a first electron emitter attached to the evacuated enclosure and configured to emit electrons;
• c) an anode attached to the evacuated enclosure and configured to emit x-rays in response to impinging electrons;
• e) an electrically conductive second electron emitter disposed within the evacuated enclosure between the first electron emitter and the anode;
• e) a voltage of the second electron emitter is greater than a voltage of the first electron emitter;
• f) a voltage of the anode is greater than a voltage of the second electron emitter;
• g) a voltage differential between the first electron emitter and the anode of at least 9 kilovolts;
• h) a voltage differential between the first electron emitter and the second electron emitter that is greater than a work function of the second electron emitter;
• i) the second electron emitter having a hole between the first electron emitter and the anode;
• j) impinging electrons on the second electron emitter, from the first electron emitter, impart energy to electrons in the second electron emitter, thus causing additional electrons to be emitted from the second electron emitter;
• k) at least ten times more electrons are emitted from the second electron emitter than are emitted from the first electron emitter;
• l) electrons from the second electron emitter accelerate towards and impinge upon the anode;
• and
• m) electrons impinging upon the anode cause the anode to emit x-rays.