Search International and National Patent Collections
Some content of this application is unavailable at the moment.
If this situation persists, please contact us atFeedback&Contact
Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters


1. A detector including an ionisation chamber .havin first (11) and second (13) electrodes, and a measuring electrode (15) disposed adjacent the exposed area of the first electrode, and means (16) for ionising gas in the chamber including the space between the three electrodes, the conducting surface of the first electr being covered by an insulation (12) except at the part of the surface adjacent the measuring electrode, characterised in that the major part of the surface of the insulator carries a conductor (41) not connected to the first electrode.

2. A detector as claimed in Claim 1 in Which the said conductor (41) is electrically connected to the second electrode (13) .

3. A detector as claimed in either of the preceding claims in which the said conductor is covered by an insulating layer (42) .

4. A detector as claimed in Claim 2 and Claim 3 in which the said conductor (41) and the insulating layer (42) comprise sleeves extending for the same distance along the length of the insulator.

5. A detector as claimed in Claim 4 in which the sleeves terminate just short of the end of the insulat which' faces the measuring electrode.