Abstract: A device comprising a pixilated semiconductor detector or VLSI chip having plurality of individual indium bumps arrayed on a surface of the detector, wherein the indium bumps are in electrical contact with the surface and are situated in defined locations on the surface is provided. Additionally, a hybrid detector comprising a pixilated detector in electrical contact with a VLSI chip, wherein electrical contacts formed from indium metal are made between the pixels of the semiconductor and regions on the VLSI chip corresponding thereto is provided. In another embodiment, a method of forming electrical contacts on a pixilated detector comprising the steps of constraining a shadow mask having an array of holes in predetermined locations above a surface on the detector, aligning the mask above the detector, and evaporating indium metal under vacuum through holes in the mask onto the surface of the detector to form the contacts is described.

Abstract: An ionization chamber is provided for the detection of nuclear radiation. The chamber is a vessel which acts as a cathode wherein at least one anode is disposed within the chamber and off-set from a center axis of the chamber. The chamber can be made from variety of shapes but is cylindrical in the preferred embodiment. The device contains two anodes in the preferred embodiment which are both off-set from the center axis. One anode collects the free floating electrons which are produced in response to particle ionization and therefore has a collected charge applied thereto. The second anode has the charge induced by immobile ions. The induced charge is subtracted from the collected charge thereby providing an improved resolution for the ionization chamber which translates into a more accurate result. In the preferred embodiment, a pressurized noble gas, such as xenon, is used.