Spectrometer Layout (Isometric View) CERN 1 m dipole Scintillator Screen Protons Electrons + Protons Camera Plasma cell Edge of scintillator screen is aligned with dipole coils (position will depend on resolution). Screen mounted at 45 degrees to beam axis. Camera is 4 m from centre of screen, mounted at 90 degrees to beam axis. Camera shown in horizontal bending plane. Camera can also be mounted vertically, directly above screen, with screen tilted at 45 degrees to vertical as well as 45 degrees to beam axis. Dipole to screen distance remains unchanged (independent of screen-camera orientation). 07/03/13 Simon Jolly, UCL, AWAKE Collaboration Meeting

Spectrometer Layout (Plan View) Electrons + Protons For left-hand bend, beam enters at right-hand edge of dipole. Protons essentially unaffected; electrons bent in dipole field. Screen mounted at 45 degrees to beam axis. Camera is 4 m from centre of screen, mounted at 90 degrees to beam axis. CERN 1 m MBPS dipole 1.6 m Electrons 1 m Protons Camera Scintillator Screen 4 m 07/03/13 Simon Jolly, UCL, AWAKE Collaboration Meeting

Spectrometer: Vacuum Vessel Electrons + Protons Screen mounted inside vacuum vessel, but camera outside. Light tight path from vacuum window to camera: doesn’t need to be permanent, just light tight… Vacuum Vessel Camera Vacuum Window Light Tight Path 07/03/13 Simon Jolly, UCL, AWAKE Collaboration Meeting

Spectrometer: Shielding Electrons + Protons Most important item to shield is CCD Camera. Needs to be as far from beamline as possible (while still close enough to receive enough light). Maximise distance to beam axis. More shielding required on upstream side. Vacuum Vessel Shielding 07/03/13 Simon Jolly, UCL, AWAKE Collaboration Meeting

Spectrometer: Vacuum Vessel Beampipe Electrons + Protons Vacuum Window Camera Light Tight Path Vacuum Vessel 07/03/13 Simon Jolly, UCL, AWAKE Collaboration Meeting