A novel radiation detector, the Intrinsic Superconducting Radiation De
tector (ISRD), is proposed. It employs the temperature dependence of t
he critical current of high T(c) superconducting films to determine th
e detector temperature change caused by incident radiation and operate
s almost exclusively in the superconducting state. The ISRD has the po
tential to be a phonon-noise-limited thermal detector.