High-voltage cage is a structure creating homogenous electric field for guiding the electrons towards the MCP. It is made of main electrodes, shaping electrodes, resistive spacers and structural elements.

The main electrodes and shaping electrodes are made of ceramic covered with NEG layer with square resitance of 60 Ohms. The application of NEG decreases the electron cloud effect (low SEY) and helps to stabilize high voltage which otherwise behaves unstably because of electron cloud and RF coupling (Jan's statement). Statement from A. Grudiev: The idea behind NEG is not for vacuum but for resistive losses, that is why the resistance of 60 Ohm is specified. This resistive losses damp the trapped modes excited by the beam in the device which can lead to beam instability and RF heating of the device.

The NEG coating was done at CERN. The coating sequence can be seen on the figures below.

The spacers have deposited a special resistive pattern with total resistance of 10 MOhm. This is done by metallux.de.

The production of spares in 2013 was done by Goodfellow (ceramic parts) and Microlan (metallic parts).