MWPC Rad Detector

STFC has developed a highly sensitive and accurate radiation detector, which can detect the amplitude and position of incoming radiation based on time analysis of the variations in the internal electric field. Advancements in the detection window make this novel detector easier and safer to both manufacture and use. The detector has potential applications in diffraction experiments of tissue, tumour diagnosis, etc. The organisation invites technical and commercial co-operation.

 

IMAGES

 

DESCRIPTION

The radiation detector is a device particularly suited for use as a multi-wire proportional counter (MWPC). The detector housing contains a window, an ionisable gas, an array of anode wires extending substantially in a first plane, and arranged to be held at a first potential. Cathode wires are spaced in a predetermined relationship from the anode wires, arranged to be held at a second, lower potential. The detector further comprises at least one additional electrode positioned adjacent a periphery of the array of anode wires, and arranged to be held at a third potential, greater than the second potential.

The window which is triple layered containing electric conductive material, a plastic layer supporting the conductive layer and a gas impermeable material. This window is substantially transparent to the radiation under scrutiny. The penetrating radiation ionises the gas in the housing, which results in the release of electrons that then move to the anode through an increasing velocity gradient. The potential of the anode array further ionises gas in its vicinity, creating an electron avalanche. This results in a net positive charge in the gas due to the positive ions, which induces a voltage on the cathode wires. The potential difference is inversely proportional to the distance between the cathode and the positive charge. The resulting voltage profile is then time analysed, allowing the determination of the position of the ionising radiation. The sensitivity and accuracy of the detector can be increased by increasing the electric field strength, which consequentially increases the amplitude of the electron avalanche, and the uniformity of the field respectively.

 

INNOVATIONS

  • The window unlike prior art does not include beryllium.

  • Presence of peripheral anode wire arrays creates a more uniform electric field.

 

ADVANTAGES

  • The absence of beryllium avoids the disadvantages related to it such as the handling and manufacturing difficulty due to its poisonous nature and brittleness.

  • The greater uniform electric field maintained by the peripheral anode arrays increases the accuracy of the detector as well as reduces the likelihood of sparking occurring. 

 

FURTHER INFORMATION

  • The electrically conductive material may have an electrical conductivity of at least 3.4 x 105 cm-1.?-1.

  • The layer of electrically conductive material may be less than 20 µm thick, usually between  4 µm and 10 µm comprising of aluminium.

  • The supporting plastic layer may comprise a polyacrylate usually polymethylmethacrylate.

  • The gas impermeable material may comprise a polyester. 

Patent Information:
For Information, Contact:
Elizabeth Bain
IP Manager
STFC Innovations
+44 (0) 1925 60 3680
elizabeth.bain@stfc.ac.uk
Keywords:
06.a. Medicine, Human Health