![Aalayah Spencer inside the Linac Coherent Light Source at the Department of Energy’s SLAC National Accelerator Laboratory. Spencer is a science and engineering associate in Experiment Control Systems at LCLS.](/sites/default/files/styles/card/public/2023-02/2022_0505_XCS_Hutch_4_Brand_Photos_Orrell-176.jpg?h=ef8607cc&itok=ZjfVh07e)
![Aalayah Spencer inside the Linac Coherent Light Source at the Department of Energy’s SLAC National Accelerator Laboratory. Spencer is a science and engineering associate in Experiment Control Systems at LCLS.](/sites/default/files/styles/card/public/2023-02/2022_0505_XCS_Hutch_4_Brand_Photos_Orrell-176.jpg?h=ef8607cc&itok=ZjfVh07e)
Photograph
SLAC staff gather in the accelerator control room to celebrate first light produced by the LCLS-II project’s pioneering superconducting accelerator.
![First light celebration](/sites/default/files/styles/card/public/2023-09/2023_0914_LCLS_II_First_Light_Celebration_Boyes-1-1180x726.jpg?h=2f3e7035&itok=GtVa1TtM)
Photograph
The original LCLS undulator system was removed and replaced with two totally new systems that offer dramatic new capabilities.
![New undulator hall](/sites/default/files/styles/card/public/2020_0306_Empty_Undulator_Hall_Gamazo-7843.jpg?h=56d0ca2e&itok=imB3yCp_)
![A schematic of a building with various pieces of cooling equipment.](/sites/default/files/styles/card/public/lclsII_2k_cooldown_sv_cryoplant_final.jpg?h=930a9827&itok=Zww49N9o)
![Cryomodule installation in the LCLS tunnel](/sites/default/files/styles/card/public/2022-09/2020_1119_Cryomodule_J1.3_20_Installation_Orrell-5.jpg?h=2fde8ad1&itok=83NR0RcQ)