Overview:
The spectrometer beamline consists of a magnetic quadrupole triplet for capturing and refocusing the beam exiting the IP, and a dipole magnet to provide vertical dispersion for energy resolved measurements.
There are three main regions for detection:
- Positron and Electron Detection Chambers (PDC/EDC)
- Chambers for diagnosing low energy (<few GeV) electrons and positrons.
- A UV spectrometer has additionally been added here (E338)
- Gamma Detection Chamber (GDC)
- To be installed in 2024.
- Future home of the Compton and Pair spectrometers for energy resolved gamma measurements.
- Dump table
- In vacuum and in air electron and photon diagnostics.
More details can be found here: https://arxiv.org/abs/2310.06215
Dump Table Diagnostics:
Below is a schematic of the (approximate) layout of the dump table as of 01/2024. Note that Gamma3 has been removed from service.
| Diagnostic | Purpose | Imaging screen | Camera + Optics | Field of View | Pixel cal.** | Imaging Res. | Additional info |
|---|---|---|---|---|---|---|---|
| DTOTR2 | ~40mm FOV electron screen TCAV measurements, E spread | YAG - 50um thickness | GigE | 40mm | ~30 um | ~50 um (YAG limited) | Watch for YAG damage! |
| DTOTR1 | High res. electron profile On the nominal e- dispersion axis | OTR or YAG | Orca FLASH Nikkor 200mm f/4 w. 200 extension | 6mm | 3.12 um | 4.5 um | Narrow depth of field |
| LFOV | Large field of view electron profile | DRZ-FINE | GigE Nikkor 50mm f/1.2 | 100mm | ~90 um | DRZ light output is decreased at points with full beam intensity | |
| LBG_LFOV | Electron profile at high dispersion Optimized for high light collection | DRZ-FINE | Orca FLASH Nikkor 50mm f/1.2 | ? | ? | ||
| CHER | Large field of view electron profile Damage resistant light emission | Cherenkov light b/w silicon wafers | GigE Nikkor 600mm f/4 | 125mm | 31 um | 250 um | Resolution limited by electron scattering |
| PRDUMP | Not used experimentally Used by ops to verify transmission to beam dump | Phosphor screen | GigE | 150 cm | |||
| GAMMA1 | Photon angular distribution | CsI(Tl) Array or DRZ-Fine with 0.1mm W convertor | GigE | 90cm | 93.4 | 0.5mm CsI pixels | |
| GAMMA2 | Photon spectral content | DRZ fine, after camembert filter | GigE Nikkor 50mm f/1.2 | 50cm | 102.4 | Requires alignment of camembert filters |
** Note - check current PV values for most up to date resolution values!
Detailed Instructions:
Instructions for how to use DOTR1 camera: DTOTR1 Instructions
Energy calibration information: Spectrometer Energy Calibration