SLAC Job Postings SLAC National Accelerator Laboratory's SPEAR3 is one of the four US third generation lightsources' electron storage rings dedicated to producing brilliant X-ray beams. SPEAR3 serves Stanford Synchrotron Radiation Lightsource (SSRL), a national user facility with the longest history of utilizing synchrotron radiation for multi-disciplinary experiments studying many of the most pressing scientific issues facing humanity including those in medicine, biology, energy, and the enviro