Intense Pulsed Neutron Source (IPNS, operation 1982-2008) was a scientific user facility  at Argonne National Laboratory for neutron scattering research. Techniques for producing pulsed slow neutron beams for condensed matter research were pioneered at Argonne using the ZGS experiment during the 1970's.
The IPNS was the world's first pulsed neutron source open to external users and started operations in 1982. The IPNS facility ceased operation in January, 2008 after the omnibus spending bill forced Basic Energy Sciences (BES) to cease IPNS operations.
During the 26 years of the IPNS operation, researchers used the IPNS to solve the fundamental questions in science while establishing the unique scientific value of this new type of neutron source. IPNS was followed by higher intensity Spallation Neutron Source (SNS) and a similar facility in the UK (ISIS).