Subsurface penetrometer radiaton sensor probe and system

A method of determining radionuclide material contamination of subsurface media comprising the steps of:

• (a) pushing a penetrometer probe unit with a protective outer housing to a desired subsurface depth thereby forming a cylindrical bore hole wall in the media, said unit containing a radiation detector means disposed within a sealed inner hollow chamber;
• (b) exposing said radiation detector means to the surrounding subsurface media formed by step (a) by detaching a detachable sleeve section containing the radiation detector means disposed within said chamber from said protective outer housing thereby reducing background radiation resulting from bremsstrahlung-scattering radiation;
• and
• (c) retrieving the radiation detector means after step (b) and collecting radiation data from the soil formation through which the detector means passes.

A system for determining radionuclide material contamination of subsurface media comprising:

• a microprocessor means for storing, displaying and analyzing the spectral data transmissions from a radiation detector means for detecting the radionuclide material contamination that is disposed within a soil penetrometer unit;
• a power means for energizing the radiation detector means;
• a signal conditioning and analog-to-digital (A/D) converter means for converting preamplified data signals from the radiation detector means;
• and
• the soil penetrometer unit including:
• external power and data transmission leads that connect the power means to the signal conditioning and A/D converter means, an inner hollow chamber and an outer soil contacting wall with a cone tip;
• the inner hollow chamber is sealed and contains the radiation detector means, an electronic signal preamplifier means for i) conditioning signals detected by the radiation detector means and ii) detecting thermal conditions of the detector means, the preamplifier means is in turn connected to the external power and data transmission leads;
• and
• a separate and detachable sleeve which forms part of the outer soil contacting wall and is adapted to separate from said unit after said unit is inserted in the subsurface whereby the radiation detector means is exposed to surrounding subsurface media after an initial penetrometer-push and separation operation has occurred.