Sample contact plate with latchable cover

A contact plate comprising:

• a base member having a sidewall extending circumferentially around a peripheral edge portion thereof to define a sample receiving area, the sidewall of the base member including an outer surface having a maximum radius, the base member further comprising a contact surface extending around the sidewall of the base member outside the sample receiving area;
• and
• a lid having a sidewall extending circumferentially around a peripheral edge portion thereof and a plurality of ribs extending from an inner surface thereof, the sidewall of the lid being configured to receive the sidewall of the base member, the ribs being configured to provide an interference fit engagement between the sidewall of the base member and the sidewall of the lid when the lid is attached to the base member, the inner surface of the lid having a minimum radius within about 0.03 centimeters (cm) of the maximum radius of the outer surface of the sidewall of the base member, the ribs extending from an inner surface of the lid having a height relative to the inner surface of the sidewall of the lid at a bottom side of the lid of between about 0.02 cm and about 0.04 cm and a width of between about 0.04 cm and about 0.06 cm;
• wherein the ribs extending from an inner surface of the lid are configured to provide a retention force of at least about 50 grams when the lid is attached to the base member and the flange member extending from the sidewall of the lid engages the contact surface of the base member independent of the rotational orientation of the lid relative to the base member on repeated attaching of the lid to the base member.