Radiation generator with field shaping electrode

A well logging tool comprising:

• a sonde housing;
• at least one radiation detector carried by said sonde housing;
• and
• a radiation generator carried by said sonde housing and comprising
• an elongate generator housing having a proximal end and a distal end,
• a target electrode within the elongate generator housing at the distal end thereof,
• a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at said target electrode based upon a first biasing potential,
• a field shaping electrode within said elongate generator housing and adjacent said charged particle source to shape a field within the elongate generator housing, and
• at least one accelerator electrode within the housing on an opposite side of said field shaping electrode from said charged particle source to accelerate charged particles from the charged particle source to the target electrode based upon a second biasing potential different than the first biasing potential,
• said field shaping electrode being coupled with said charged particle source so that the charged particles are directed from said charged particle source to said target electrode without applying a biasing potential to said field shaping electrode that is different than a biasing potential applied to said charged particle source.

A method for making a radiation generator comprising:

• positioning a target electrode within an elongate generator housing at a distal end thereof, and positioning a charged particle source within the elongate generator housing at a proximal end thereof to direct charged particles at the target electrode based upon a first biasing potential;
• positioning a field shaping electrode within the elongate generator housing and adjacent the charged particle source to shape a field within the elongate generator housing;
• and
• positioning at least one accelerator electrode within the housing on an opposite side of the field shaping electrode from the charged particle source to accelerate charged particles from the charged particle source to the target electrode based upon a second biasing potential different than the first biasing potential;
• the field shaping electrode being coupled with the charged particle source so that the charged particles are directed from the charged particle source to the target electrode without applying a biasing potential to the field shaping electrode that is different than a biasing potential applied to the charged particle source.