Machine Description and status


The Accelerator Operation Group is one of the groups in the technical division at SESAME, composed of three operators till now. The operation group works in a close collaboration with the other groups in the technical division to support and organize the accelerator’s operation, and to enhance the performance of them.

We are responsible for the round-the-clock operation of the synchrotron light source machine, working, together with the other technical groups, on delivering a stable, high quality beam to the users, and documenting the specific operation results. We are working constantly on improving beam availability, minimizing the machine downtime during the user time, coordinating & scheduling the shutdown and machine-dedicated time activities, and operation in general.

SESAME has three main accelerators: a 22MeV Microtron, 800MeV Booster and 2.5GeV Storage Ring (See Figure1) with maximum operational current 250mA, till now. The design current value is 400mA.


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) = 26 Booster 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 = 60.5mm Three-pole wiggler (ID10): It delivers a single source hard X-Ray photon beamMinimum gap = 11.15mmMaximum magnetic feld = 2.9T Apple-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

We offer only one filling pattern in SESAME storage ring where around 3 quarters of the storage ring are filled with electrons while the 4th one is kept empty. No other filling patterns are used yet. The Booster-to-storage ring injection is done at 800MeV, then the storage ring energy is ramped to 2.5GeV in a 6-minute period. The storage ring is running in the decay mode with only one injection per day due to the sufficient beam lifetime.

The offered 250mA beam is stable which made no need for feedback systems yet. However, a fast orbit feedback will be needed when Insertion Devices with variable-gap-operation modes are used.

The machine has been operated for a total of 3948 h in 2019, the second year of machine operation as a user facility, 2388 h of them were dedicated for users.

The machine has currently 3 operational beamlines (XAFS, IR, and Material Science beamlines) with other two beamlines (Tomography and Soft X-RAY beamlines) under construction and expected to be operational by end 2022.

Accelerator Operator
Work Tel: +962 5 351 1348  (Ext. 254)