Storage Ring Main Parameters
| Energy | 3 GeV |
| Circumference | 561.571 m |
| Maximum beam current | 300 mA |
| Horizontal emittance* | 3.14 nm rad |
| Vertical emittance | 8 pm rad |
| Revolution frequency | 533.8 kHz |
| RF frequency | 499.680 MHz |
| Maximum no. of bunches | 936 |
| Time between bunches | 2.0 ns – 1.87 µs |
| Bunch length*# (rms) | 17.1 ps (0.62nC bunch current) |
*Values calculated assuming I12 and I15 wigglers at full field
#Values for 2.5 MV cavity voltage
Filling Patterns
The storage ring can be filled with an arbitrary bunch pattern, subject to a current limit which depends on the number of bunches, and a maximum limit of 300 mA. The following are the bunch patterns that are currently offered to users:
1. Standard mode
900 contiguous bunches, 2 ns apart, each with a charge of 0.62 nC (0.33 mA), with a gap in the bunch train of 72 ns; total current = 300 mA.
2. Hybrid mode
A train of contiguous bunches (typically between 686 and 836 bunches in length), 2 ns apart, plus a single/group of bunches centered in the gap with charge in the range 0.67 nC to 6 nC (0.36 mA to 3.2 mA). Total current is maintained at 300 mA. Please contact Diamond directly for details of a specific filling pattern in use on a given date.
3. 156 bunch mode
156 bunches equally spaced, 12 ns apart, each with a charge of 1.63 nC (0.87 mA);
total current = 136 mA.
Source sizes and divergences (electrons)*#
rms values, valid in standard and hybrid modes. Vertical size and divergence are increased by a factor 1.22 in 156-bunch mode.
| Source | Horizontal size (µm) | Vertical size (µm) | Horizontal divergence (µrad) | Vertical divergence (µrad) | ||
| I02: VMXi | 121.6 | 4.1 | 32.6 | 2.0 | ||
| J02: VMXm | 92.1 | 4.4 | 45.9 | 1.8 | ||
| I03 | 109.5 | 4.0 | 34.5 | 2.0 | ||
| I04 | 146.9 | 3.9 | 24.8 | 2.2 | ||
| I04-1 | 155.7 | 6.6 | 24.8 | 2.2 | ||
| I05: ARPES | 192.9 | 7.1 | 18.5 | 1.1 | ||
| I06: Nanoscience | A | 148.4 | 4.8 | 26.7 | 2.3 | |
| B | 133.4 | 4.2 | 26.7 | 2.3 | ||
| I07: Surface and Interface Diffraction | 120.3 | 3.4 | 29.2 | 2.3 | ||
| B07: VERSOX | B | 57.8 | 15.0 | 131.6 | 1.6 | |
| C | 48.9 | 14.8 | 118.1 | 1.6 | ||
| I08: SXM | 139.6 | 3.6 | 26.2 | 2.3 | ||
| I09 | Hard x-ray | 255.1 | 3.0 | 21.4 | 2.7 | |
| Soft x-ray | 315.5 | 3.5 | 23.0 | 2.3 | ||
| I10: BLADE | A | 155.5 | 5.1 | 26.4 | 2.2 | |
| B | 149.3 | 4.1 | 26.4 | 2.2 | ||
| I11: High Resolution Powder Diffraction | 141.7 | 3.6 | 29.4 | 2.2 | ||
| K11: DIAD | 246.7 | 12.8 | 175.8 | 5.3 | ||
| I12: JEEP | 153.2 | 3.4 | 25.9 | 2.3 | ||
| I13 | I13-2: Imaging | 263.6 | 2.9 | 26.4 | 2.8 | |
| I13-1: Coherence | 302.7 | 3.6 | 18.5 | 2.2 | ||
| I14 | 142.7 | 3.9 | 26.3 | 2.1 | ||
| I15 | 119.8 | 3.4 | 29.5 | 2.3 | ||
| I15-1 | 119.8 | 3.4 | 29.5 | 2.3 | ||
| I16: Materials and Magnetism | 135.5 | 3.5 | 26.7 | 2.3 | ||
| B16 | 55.1 | 14.6 | 123.4 | 1.2 | ||
| I18: Microfocus Spectroscopy | 140.9 | 3.9 | 26.1 | 2.1 | ||
| B18 | 50.0 | 15.0 | 121.5 | 1.4 | ||
| I19 | 124.9 | 3.6 | 29.6 | 2.3 | ||
| I20: Scanning | 143.9 | 3.5 | 26.1 | 2.3 | ||
| I20: EDE | 162.0 | 5.3 | 26.1 | 2.3 | ||
| I21: RIXS | 181.0 | 5.2 | 19.8 | 1.6 | ||
| B21: Solution State SAXS | 54.2 | 15.4 | 122.7 | 1.5 | ||
| I22 | 141.6 | 3.5 | 25.7 | 2.3 | ||
| B22: MIRIAM | 52.5 | 15.6 | 129.5 | 1.6 | ||
| I23: Long Wavelength MX | 115.5 | 3.4 | 30.1 | 2.4 | ||
| B23: Circular Dichroism | 53.7 | 15.2 | 125.1 | 1.6 | ||
| I24 | 136.1 | 3.5 | 27.5 | 2.3 | ||
| B24: Cryo-TXM | 52.0 | 14.5 | 118.9 | 1.3 | ||
*Values calculated assuming I12 and I15 wigglers at full field
#Values refer to the centre of the ID for ID beamlines, and at the angle through the bending magnet around which the beamlines are centred for bending magnet beamlines
Twiss parameters at the source-points*#
Valid in standard and hybrid modes only. Different values are in use during low-alpha operation.
| Source | βx (m) | αx | βy (m) | αy | Dx (m) | Dx’ | ||
| I02: VMXi | 3.392 | 0.316 | 2.094 | 0.123 | 0.060 | -0.006 | ||
| J02: VMXm | 1.528 | 0.142 | 2.395 | -0.013 | 0.057 | -0.002 | ||
| I03 | 2.690 | -0.104 | 2.047 | -0.130 | 0.056 | 0.003 | ||
| I04 | 5.115 | -0.020 | 1.910 | -0.372 | 0.069 | 0.001 | ||
| I04-1 | 5.886 | -0.389 | 5.430 | -1.469 | 0.071 | 0.001 | ||
| I05: ARPES | 9.237 | 0.009 | 6.361 | -0.105 | 0.084 | -0.001 | ||
| I06: Nanoscience | A | 5.467 | 0.448 | 2.825 | 0.954 | 0.065 | -0.004 | |
| B | 4.584 | -0.082 | 2.157 | -0.676 | 0.054 | -0.004 | ||
| I07: Surface and Interface Diffraction | 3.692 | -0.019 | 1.450 | -0.034 | 0.050 | 0.000 | ||
| B07: VERSOX | B | 0.693 | 0.528 | 28.027 | 2.860 | 0.032 | -0.100 | |
| C | 0.596 | 0.319 | 27.379 | 2.823 | 0.021 | -0.084 | ||
| I08: SXM | 4.862 | -0.171 | 1.579 | -0.198 | 0.060 | 0.005 | ||
| I09 | Hard x-ray | 16.964 | 1.184 | 1.111 | -0.101 | 0.101 | -0.004 | |
| Soft x-ray | 24.608 | 1.603 | 1.568 | -0.286 | 0.139 | -0.008 | ||
| I10: BLADE | A | 5.573 | 0.468 | 3.238 | 0.950 | 0.076 | 0.003 | |
| B | 4.595 | -0.071 | 2.123 | -0.498 | 0.083 | 0.003 | ||
| I11: High-Res Powder Diffraction | 3.632 | -0.016 | 1.597 | 0.122 | 0.087 | 0.001 | ||
| K11: DIAD | 8.459 | 5.856 | 20.613 | -8.489 | 0.173 | -0.124 | ||
| I12: JEEP | 4.888 | -0.188 | 1.463 | -0.022 | 0.084 | -0.002 | ||
| I13 | I13-2: Imaging | 16.589 | 1.381 | 1.020 | -0.004 | 0.123 | -0.011 | |
| I13-1: Coherence | 23.153 | 0.960 | 1.651 | -0.199 | 0.128 | -0.008 | ||
| I14 | 4.928 | 0.187 | 1.879 | 0.266 | 0.065 | -0.005 | ||
| I15 | 3.629 | 0.027 | 1.476 | 0.133 | 0.051 | -0.001 | ||
| I15-1 | 3.629 | 0.027 | 1.476 | 0.133 | 0.051 | -0.001 | ||
| I16: Materials and Magnetism | 4.702 | -0.204 | 1.529 | -0.067 | 0.056 | 0.004 | ||
| B16 | 0.669 | 0.752 | 26.723 | 1.956 | 0.028 | -0.083 | ||
| I18: Microfocus Spectroscopy | 4.830 | 0.204 | 1.905 | 0.301 | 0.064 | -0.002 | ||
| B18 | 0.489 | 0.148 | 27.965 | 2.459 | 0.029 | -0.084 | ||
| I19 | 3.595 | -0.004 | 1.623 | 0.209 | 0.061 | 0.001 | ||
| I20: Scanning | 4.831 | -0.186 | 1.488 | 0.109 | 0.069 | 0.003 | ||
| I20: EDE | 6.303 | -0.591 | 3.516 | -1.179 | 0.075 | 0.003 | ||
| I21: RIXS | 8.103 | -0.035 | 3.346 | 0.125 | 0.080 | -0.002 | ||
| B21: Solution State SAXS | 0.485 | 0.562 | 29.685 | 2.645 | 0.035 | -0.075 | ||
| I22 | 5.216 | 0.212 | 1.515 | 0.192 | 0.056 | -0.005 | ||
| B22: MIRIAM | 0.452 | 0.130 | 30.457 | 2.907 | 0.034 | -0.092 | ||
| I23: Long Wavelength MX | 3.493 | 0.067 | 1.404 | 0.008 | 0.045 | 0.000 | ||
| B23: Circular Dichroism | 0.669 | 0.349 | 29.043 | 2.954 | 0.026 | -0.095 | ||
| I24 | 4.648 | -0.255 | 1.498 | -0.178 | 0.058 | 0.005 | ||
| B24: Cryo-TXM | 0.664 | 0.758 | 26.366 | 2.047 | 0.023 | -0.076 | ||
*Values calculated assuming I12 and I15 wigglers at full field
#Values refer to the centre of the ID for ID beamlines, and at the angle through the bending magnet around which the beamlines are centred for bending magnet beamlines
“Low-alpha” mode
This special operating mode utilises a different storage ring “optics” to the standard, hybrid and 156-bunch modes, in order to create short electron bunches, with low beam current. The main parameters of this mode, which has two varieties, are as follows:
| | Stable Mode | Bursting Mode |
| Momentum compaction factor | -6 10-6 | -6 10-6 |
| Number of bunches | 400 | 234, evenly spaced |
| Horizontal emittance | 5.1 nm rad | 5.1 nm rad |
| Vertical emittance | 51 pm rad | 51 pm.rad |
| Bunch charge (current) | 47 pC (25 µA) | 80 pC (43 µA) |
| Total beam current | 10 mA | 10 mA |
| Bunch length (rms) | 3.5 ps | 3.5 ps |
The difference between these two modes is that in the case of the “Bursting mode”, the bunch charge is above an instability threshold which enhances the emission of coherent THz radiation. Source sizes and diverges are different to those of the standard, hybrid and 156-bunch modes.
Last updated 25/11/2019
For further information contact [email protected]
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