An ultra-high vacuum (UHV) system includes a UHV cell and an ion pump to maintain the UHV in the UHV cell. The ion pump has a GCC (glass, ceramic, or crystalline) housing. An interior wall of the ion-pump housing serves as an anode or bears a coating that serves as an anode. At least one cathode is disposed with respect to the housing so that it can cooperate with the anode to form an electric field for establishing a Penning trap. The GCC housing defines a flow channel that extends radially through the anode so that a molecule can flow directly into the most ionizing region of a Penning trap.