SESAME’s Accelerators

The synchrotron radiation at SESAME is produced at electron energy 2.5GeV. The electron acceleration process takes place through three accelerators. The injector system (consists of a 20 MeV microtron and 800MeV booster synchrotron) fills the storage ring with electrons at 800MeV. The kinetic energy of the electrons is then ramped to a 2.5GeV in the storage ring that is used as a synchrotron during the daily refill phase. 

Electron beam keeps circulating in the storage ring that is maintained at a very low pressure (around 10-9 mbar) by the vacuum system. The electrons in the storage ring are guided by a set of bending and focusing magnets to ensure that they remain focused in a small cross section and close to their ideal orbital path. The beam behavior is monitored by the diagnostic system. The radiation emitted in dipole magnets or insertion devices is collected at the beamlines’ front-ends and then guided along the beamlines’ optical elements to the experiment. The energy released as a synchrotron radiation in each turn is restored to the electron beam by four radio frequency cavities. The electrical and radiation heat deposited into the storage ring, front-ends and beamlines’ components is cooled down by the cooling system.  All the mentioned operation process is managed by the control system.

 

BM08-XAFS/XRF (X-ray Absorption Fine Structure /X-ray Fluorescence Spectroscopy Beamline) ID09-MS/XPD(Materials Science/X-ray Powder Difraction Beamline) ID10-BEATS (BEAmline for Tomography at SESAME) ID11L-HESEB (HElmholtz-SEsame Beamline for soft X-ray light) ID11R-TXPES (Turkish soft X-rayPhotoelectron Spectroscopy Beamline) BM02-IR (Infrared Spectromicroscopy Beamline) SESAME storage ring parameters:Energy (GeV) = 2.5 Current (mA) = 400 Circumference (m) = 133.2 Natural emittance (nm.rad) = 26Booster Synchrotron:Provides more acceleration to the electron beam and transfers it to the storage ring.Microtron:Generates and pre-acceleratesthe electron beam.Storage Ring Radio Frequency Cavity:Accelerates the electron beam during energy ramping and restores the energy lost by the circulating electron beam as it emits the synchrotron light.Transfer Line (TL2):Transfers the Booster electron beam to the Storage Ring.Transfer Line (TL1):Transfers the Microtron electron beam to the Booster Synchrotron.Storage Ring Bending Magnet (B= 1.455T):Deflects the electron beam with angle to keep it circulating inside the Storage Ring’s doughnut-shaped vacuum chamber.It is also the basic location where the electron beam emits synchrotron light.Storage Ring Focusing Magnets:Focus the circulating electron beam and control its characteristics.Multipole wiggler (ID09):Minimum gap = 12mmMaximum magnetic feld = 1.38TPeriod length = 60.5mmThree-pole wiggler (ID10):It delivers a single source hard X-Ray photon beamMinimum gap = 11.15mmMaximum magnetic feld = 2.9TApple-II Undulator (ID11):It delivers a soft X-Ray photon beam of a tunable polarizationMinimum gap = 13.4mmMaximum magnetic feld (@zero shift) = 1.0TPeriod length = 56mm

Schematic overview of SESAME

Tab