PT Journal AU Gershenson, ME Gong, D Sato, T Karasik, BS Sergeev, AV TI Millisecond electron-phonon relaxation in ultrathin disordered metal films at millikelvin temperatures SO Appl. Phys. Lett. PY 2001 BP 2049 EP 2051 VL 79 DE HEB detector; FIR; far infrared ER