  This paper describes the concept for the DArk Sector Experiments at LCLS-II
(DASEL) facility which provides a near-CW beam of multi-GeV electrons to the
SLAC End Station A for experiments in particle physics. The low-current
multi-GeV electron beam is produced parasitically by the superconducting RF
linac for the LCLS-II X-ray Free Electron Laser, which is under construction at
SLAC. DASEL is designed to host experiments to detect light dark matter such as
the Light Dark Matter eXperiment (LDMX) but can be configured to support a wide
range of other experiments requiring current ranging from pico-amps to
micro-amps.
