High-Performance Experimental Facilities
SSRL utilizes x-rays produced by its accelerator, the Stanford Positron Electron Asymmetric Ring (SPEAR3). Based on a 2004 upgrade funded by the Department of Energy and the National Institutes of Health, SPEAR3 is a 3-GeV, high-brightness third generation storage ring operating with high reliability and low emittance. SSRL runs with 500 mA in top-off mode, during which the beam current is kept constant with injection of electrons into the ring every five minutes. The SPEAR3 ring recently completed a project to reduce its emittance to 7 nm-radians.
SSRL continually works to improve SPEAR3 to remain competitive with synchrotron light sources around the world, including:
- Accelerator performance improvements in beam quality (brightness, stability and optimization for timing mode experiments) injector enhancements.
- Accelerator reliability improvements along with improvements in spare availability
- Accelerator research and development that prioritizes future accelerator performance upgrades
3 GeV
Electron storage ring
Beam Status
Current
Loss Rate
SPEAR3 Program Announcements
| Beam Line | Status | Steering | Periods | Gap (mm) | Field(T) | K | Power (W) | Yield (Ah) |
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Photon Source Parameters
| Parameter | Value |
|---|---|
| Beam Energy | 3 GeV |
| Injection Energy | 3 GeV |
| Current | 500 mA |
| Fill Pattern | 276 bunches distributed in 4 groups of 69 bunches each, plus 1 "camshaft" bunch |
| Circumference | 234.137 m |
| Radio Frequency | 476.315 MHz |
| Bunch Spacing | 2.1 ns |
| Horizontal Emittance | 7 nm*rad |
| Vertical Emittance | 8 pm*rad |
| Critical Energy | 7.6 keV |
| Energy Spread | 0.10% |
| Lifetime | 6 hours |
| e- size (x,y) | Dipole: 123, 11 µm rms Standard ID: 270, 6.6µm rms Chicane ID: 296, 3.6 µm rms Matching ID: 249, 4.5 µm rms |
| e- divergence (x,y) | Dipole: 165, 2.3 µrad rms Standard ID: 28, 1.25 µrad rms Chicane ID: 27, 2.3 µrad rms Matching ID: 27, 1.8 µrad rms |
| Bunch Length | 20 psec rms (6.1 mm rms) |
| Straight sections for IDs (available ID length) | 9 x 2.3 m 4 x 3.7 m 2 x 1.5 m (Chicane) |