General parameters:
Species: electrons or positrons
Circumference: 768.438 m
Circulation time: 2.562 us
Energy range: 1.0-6.0 GeV
Cell structure: None - all magnets independently powered
Majority of ring is comprised of FODO-type structure
CHESS-U Upgrade consists of six double-bend achromats (DBAs) through CHESS source region (approx. 1/6 of circumference)
RF parameters:
RF Frequency: 500 MHz
RF period: 2ns
# RF Cavities: 4
Harmonic number: 1281
Voltage: 1.5 MV/cavity, 6.0MV total
Bunch Length: 17 mm = 57 ps (at 6.0GeV)
CHESS Operating Conditions:
Optics and General Parameters:
Species: positrons
Energy: 6.0GeV
Design current: 200 mA
Horizontal Emittance:
-Without IDs: 29.6 nm-rad
-With all IDs: 27.7 nm-rad
Emittance coupling: 1%
Tunes (x, y): (16.556, 12.635)
Natural Chromaticities (x, y): -27.6, -26.2
Momentum Compaction: 5.734E-3
Energy loss/turn: 2.105 MeV/turn
Damping times:
Horizontal: 4669 turns = 12.0 ms
Vertical: 5682 turns = 14.5 ms
Longitudinal: 3211 turns = 8.2 ms
Lifetime: 15 hrs at 100 mA
Topoff Interval: 10 min at 100 mA
Correction interval: 10 sec
Pulse structure:
Bunch pattern: 9 evenly-spaced trains of 5 bunches/train
Bunch spacing: 14ns
Train spacing: 280ns between first bunch of each train
Bunch charge: 4.44 mA/bunch = 11.4 nC/bunch
For Specific Information on each beam-line and the experiments running there please visit our Beamline Directory
Source parameters:
Sector 1: 1A2, 1A3
Partner: MSN-C
Source: 24-pole wiggler
beta_x = 7.78 m, alpha_x = -0.69
beta_y = 4.08 m, alpha_y = 0.05
eta_x = 0 , eta_x' = 0
sigma_x = 463.7 μm
sigma_x' = 72.3 μrad
sigma_y = 33.6 μm
sigma_y' = 8.2 μrad
Sectors 2, 3, 4: 2A, 3A, 3B, 4B
Partners: CHEXS, MSN-C
Source: CHESS Compact Undulator (CCU), canted pair
beta_x = 11.5 m, alpha_x = 0
beta_y = 2.6 m, alpha_y = 0
eta_x = 0 , eta_x' = 0
sigma_x = 565.9 μm
sigma_x' = 49.1 μrad
sigma_y = 28.8 μm
sigma_y' = 10.4 μrad
Canting angle: 2 mrad separation
Sector 7A: 7A
Partners: CHEXS, MacCHESS
Source: CHESS Compact Undulator (CCU)
beta_x = 10.5 m, alpha_x = 0.38
beta_y = 3.4 m, alpha_y = 0.32
eta_x = 0 , eta_x' = 0
sigma_x = 539.6 μm
sigma_x' = 54.8 μrad
sigma_y = 30.7 μm
sigma_y' = 9.5 μrad
Canting angle: 1 mrad separation between 7A and 7B
Sector 7B: 7B
Source: CHESS Compact Undulator (CCU)
beta_x = 9.5 m, alpha_x = 0.16
beta_y = 3.4 m, alpha_y = -0.33
eta_x = 0 , eta_x' = 0
sigma_x = 511.4 μm
sigma_x' = 54.8 μrad
sigma_y = 30.7 μm
sigma_y' = 9.5 μrad
Canting angle: 1 mrad separation between 7A and 7B
Center for High-Energy X-ray Sciences at CHESS (CHEXS at CHESS) is supported by the National Science Foundation, NSF.
The National Institute of Health (NIH) and New York State (through NYSTAR) jointly support facilities for macromolecular X-ray science at CHESS (MacCHESS).
The Materials Solutions Network at CHESS (MSN-C) is supported by the Air Force Research Lab (AFRL).