Preparation of Cryogenic Sample for Charged-Particle Microscopy

An apparatus for plunge-cooling a sample for study in a charged-particle microscope, which sample is provided on a substantially planar sample holder, the apparatus comprising:

• an arm that can be used to grip an edge of said sample holder and retain it in a substantially horizontal orientation;
• a container that can be at least partially filled with a bath of cryogen, such that said cryogen has an exposed upper surface at a given horizontal level;
• a dropping mechanism that can be used to move said arm into said container, allowing a sample holder in said arm to be plunged below said horizontal level, with a front side of the sample holder pointing downward;
• and
• a dosing mechanism for applying a controllable blast of cryogenic fluid to a backside of said sample holder;
• a controller connected to said dropping mechanism and said dosing mechanism, for timing said blast to occur immediately prior to the sample holder crossing said horizontal level.

A method of preparing a sample for observation in a charged particle beam system, comprising:

• providing a sample holder having a first major surface and an opposing second major surface, the sample holder supporting a sample having containing one or more specimens of interest;
• orienting the sample holder with the first major surface facing toward a cryogenic bath and the second major surface facing away from the cryogenic bath;
• applying a cryogenic fluid to the second major surface of the sample holder;
• plunging the sample holder into the cryogen bath immediately after applying the cryogenic fluid to the second major surface.