Abstract: This invention relates to cryopumps, and consists in the incorporation of walls for trapping by condensation exemplified by outer faces of partitions, and walls for trapping by adsorption, exemplified by inner faces of these partitions. These walls define a confined area in the closed position, in which the adsorbent is isolated from condensable gases. Once these gases have been condensed on the said outer faces, the partitions are opened to place the adsorbent layers in communication with the remainder of the pumping enclosure.The invention is applicable to the production of high and uncontaminated vacua (in particular for the production of thin films).