Semiconductor anode photomultiplier tube
AssigneeBurle Technologies, Inc.
InventorCharles M. Tomasetti
Life of this patent
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Abstract
A photomultiplier tube in which the a semiconductor photodiode serves as the anode and receives the electrons from the photocathode. The particular geometry for the focusing electrodes in the tube involves a two part structure with one part, the anode focus electrode, in close proximity to the semiconductor photodiode. The second part of the focus structure is a grid focus electrode with two different diameters, located approximately midway between the photodiode and the photocathode and operating on a low voltage. Together the electrodes create a focusing electric field so that the electrons from the large area photocathode are efficiently delivered to the small area of the semiconductor photodiode. The mounting of the photodiode is also designed to act as a termination to furnish superior timing characteristics.
Claims9
A photomultiplier tube comprising:
- a sealed envelope from which all gases have been evacuated to form a vacuum suitable for operation of a electron tube within the sealed envelope;
- a window which forms a part of the sealed envelope and through which radiation can pass;
- a photocathode located on the inside surface of the window, the photocathode emitting electrons when affected by radiation passing through the window, the photocathode having a first voltage applied to it;
- a semiconductor photodiode located within the sealed envelope and having a second voltage applied to it, the semiconductor photodiode generating an electrical signal on output connections when it is contacted by electrons from the photocathode, with the electrical signal varying with the quantity of electrons contacting the semiconductor photodiode;
- at least an anode focus electrode and a grid focus electrode located within the sealed envelope in the region between the photocathode and the semiconductor photodiode with the anode focus electrode being nearer to the semiconductor photodiode, the focus electrodes being formed of electrically conductive material and having a third electrical voltage applied to the grid focus electrode and a fourth electrical voltage applied to the anode focus electrode so that a focus electrical field is formed within the sealed envelope to direct electrons leaving the photocathode to the semiconductor photodiode.
Dependencies are inferred from the claim text.