Extreme high vacuum apparatus

Claim 1

A HIGH-VACUUM CHAMBER, COMPRISING IN COMBINATION (A) A VACUUM-TIGHT HORIZONTALLY ORIENTED CYLINDRICAL INNER VESSEL; (B) MEANS FOR CIRCULATING A CRYOGENIC FLUID IN HEAT TRANSFER RELATIONSHIP WITH THE OUTER WALL OF SAID INNER VESSEL; (C) AN EXPERIMENTAL VACUUM CHAMBER LOCATED AT ONE END OF SAID INNER VESSEL ADAPTED TO BE ACCESSIBLE FOR INSERTION AND WITHDRAWAL OF AN EXPERIMENTAL BODY; (D) CONDUIT MEANS AT THE OTHER END OF SAID INNER VESSEL AND COMMUNICATING WITH VACUUM PUMP MEANS; (E) CRYOPUMPING SURFACE MEANS LOCATED WITHIN SAID INNER VESSEL BETWEEN SAID EXPERIMENTAL VACUUM CHAMBER AND SAID CONDUIT MEANS; (F) MEANS SEPARATE FROM (B) FOR BRINGING A CRYOGENIC FLUID IN HEAT EXCHANGE RELATIONSHIP WITH SAID CRYOPUMPING SURFACE MEANS THEREBY TO MAINTAIN THEM AT A CRYOPUMPING TEMPERATURE; (G) RADIATION SHIELD MEANS WITHIN SAID INNER VESSEL BETWEEN SAID CRYOPUMPING SURFACE MEANS AND SAID EXPERIMENTAL VACUUM CHAMBER, AND (H) AN OUTER VACUUM-TIGHT HORIZONTALLY ORIENTED CYLINDRICAL VESSEL IMMEDIATELY SURROUNDING SAID INNER VESSEL AND DEFINING AN EVACUATABLE GUARD VOLUME AROUND SAID INNER VESSEL.