Short answers, pulled from the story.
The SPEAR particle physics collider at SLAC National Accelerator Laboratory collided electrons and positrons to reveal the existence of previously unseen particles. This machine operated as an engine of discovery that fundamentally altered humanity's understanding of matter. It recorded data using the Mark I detector to lead to the discovery of the J/psi meson.
The SPEAR collider discovered the J/psi meson in 1974 during experiments that became known as the November Revolution. This specific particle earned the 1976 Nobel Prize in Physics for its discoverers. The finding provided the first direct evidence for the existence of the charm quark.
Martin Perl and his team discovered the tau lepton at SPEAR in 1975. This heavy cousin of the electron and muon was the third generation of leptons and completed a pattern missing from the Standard Model. The discovery of the tau lepton was awarded the 1995 Nobel Prize in Physics to Martin Perl.
The SPEAR facility shifted from a collider to a dedicated synchrotron radiation source known as SPEAR2. This transition allowed electrons to spiral through the ring to emit X-rays and ultraviolet light for use in materials science, biology, and chemistry. The beamlines of SPEAR2 became a hub for researchers to study the atomic structure of complex molecules.
A major upgrade completed in 2004 transformed SPEAR into SPEAR3, a state-of-the-art light source. The upgrade included new magnets, vacuum systems, and beamline instrumentation that enhanced the brightness and stability of the synchrotron radiation. SPEAR3 became capable of producing light across a wide range of wavelengths from infrared to hard X-rays.