Technical overview of ELSA
History And Status
| Construction started: | June 1983 |
| First beam: | February 1988 |
| Total cost of facility: | 18.6 MDM |
| Ann. operating time: | up to 3000 h |
Accelerator Parameters
- General
| Accelerated particles: | electrons |
| Energy: | 0.5 - 3.5 GeV |
| Ring circumference: | 164.4 m |
| Tunnel sect. (W x H): | 2.5 m x 2.3 m |
- Injector system: LINAC
| LINAC 2: | 26 MeV, source of polarized electrons (pol. appr. 80 %) |
- Booster Synchrotron
| Type: | 50 Hz fast cycling synchrotron |
| Output: | max. 500 nA at 0.5 - 1.6 GeV |
| Injection period: | 0.45 usec or 0.8 turns of ELSA |
| Inflector type: | septum magnet |
- Magnet System
| Focusing type: | AG, seperated function |
| Focusing order: | FODO |
| Betatron tune: | (for extraction) hor. 4.64, vert. 4.60 |
| No. of Dipols: | 24 Length: 2.84 m |
| Bending field: | max. 1.07 T |
| No. of Quadrupols: | 32 (+4 aircore) Length: 0.45 m |
| Gradient: | max. 7.7 T/m |
| No. short straight sect.: | 24 Length: 1.50 m |
| No. long straight sect.: | 8 Length: 4.69 m |
| Rise time: | 0.2-5 s |
| Flat-top-time: | 0.5-140 s
(relevant for post-accelerator mode of operation only) |
| Power input | peak: 3.7 MW, mean: 1.6 MW |
- Acceleration RF System
| RF frequency: | 499.67 MHz |
| Harmonic number: | 274 |
| No. cavities: | 2 |
| Length: | 1.5 m |
| RF power input peak: | 250 kW |
| Radiation loss: | 1225 keV/turn at 3.5 GeV |
- Vacuum System
| Material of vac. chamber: | stainless steel |
| Aperture of vac. chamber: | typically 100 mm x 50 mm |
| Average pressure: | 5 . 10-9 mbar (without beam) |
- Extraction System
| Method: | hor. betatron resonance Q = 4 2/3 |
| | resonance strength controlled by sextupoles |
| Rate control: | spillout controlled by ironless quads |
| Length of spill: | 20 ms to 60 s |
Accelerator Performance
- Modes of operation
| Mode 1: | Stretcher |
| Mode 2: | Post-accelerator |
| Mode 3: | Synchrotron Radiation Source |
- Energy
| Mode 1: | 0.5 - 1.6 GeV |
| Mode 2: | 0.5 - 3.5 GeV |
| Mode 3: | 1.6 - 3.0 GeV |
- Intensity
- internal beam:
| Mode 1: | 2 - 10 mA |
| Mode 2: | 15 - 80 mA |
| Mode 3: | 25 - 250 mA |
- external beam:
| Mode 1: | 10 pA - 100 nA |
| Mode 2: | 1 pA - 20 nA |
- Duty Factor
- 98% (macroscopic), 60% (with microstructure)
- up to 95% (macroscopic), up to 85% (with microstructure)
(depending on the final energy and the intensity of the
external beam)
- Lifetime in SR mode: up to 6 h (25 mA at 2.3 GeV)
- Research Program
- Electron beamlines: 3
- SR beam lines: 1
- Number of users
| electron beams: | 2 international collaborations |
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