Radiation generator with frustoconical electrode configuration

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, and
• a plurality of accelerator electrodes spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section, each accelerator electrode comprising:
• an annular portion having a first opening therein, and
• a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first opening and the second opening to reach the target electrode.

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;
• and
• positioning a plurality of accelerator electrodes within the elongate generator housing between the target electrode and the charged particle source and spaced apart from one another to define a charged particle accelerator section, each accelerator electrode comprising:
• an annular portion having a first opening therein, and
• a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first opening and the second opening to reach the target electrode.