  The 75,848 lead tungstate crystals in CMS experiment at the CERN Large Hadron
Collider are used to measure the energy of electrons and photons produced in
the proton-proton collisions. The optical transparency of the crystals degrades
slowly with radiation dose due to the beam-beam collisions. The transparency of
each crystal is monitored with a laser monitoring system that tracks changes in
the optical properties of the crystals due to radiation from the collision
products. Predicting the optical transparency of the crystals, both in the
short-term and in the long-term, is a critical task for the CMS experiment. We
describe here the public data release, following FAIR principles, of the
crystal monitoring data collected by the CMS Collaboration between 2016 and
2018. Besides describing the dataset and its access, the problems that can be
addressed with it are described, as well as an example solution based on a Long
Short-Term Memory neural network developed to predict future behavior of the
crystals.
