Medium Background Infrared (MBIR) Facility

The MBIR facility is located in a soft-wall class 10 000 clean room. The vacuum chamber has a diameter of 120 cm and a length of 180 cm with internal light-tight radiation shrouds which are currently operated at 80 K using liquid nitrogen cooling. Inside the cooled shrouds is a rollout optical table, which permits large instruments, up to 61 cm high by 91 cm wide. Active temperature control of the internal components allows the table temperature to be maintained near 80 K. Ten temperature sensors are attached to the shrouds and the table to permit recording of the temperatures of the various sections of the inside surfaces. The chamber is evacuated using a large oil-free pump and the vacuum maintained by a cryogenic pump. The base pressure is approximately 1.33 × 10^-4 Pa (1 × 10^-6 Torr) without liquid nitrogen in the shrouds. With the shrouds at 80 K, the pressure is approximately 1.33 × 10^-5 Pa (1 × 10^-7 Torr). All of the physical functions of the chamber, such as pump-down and cooling sequences, will be automated using appropriate computer hardware and a multitasking control program. With heaters, the shroud temperature could be controlled from 80 K to 325 K. ACR is used to calibrate the TXR, a portable thermal infrared transfer radiometer.


References The new cryogenic vacuum chamber and black-body source for infrared calibrations at the NIST's FARCAL facility, J.B. Fowler, B.C. Johnson, J.P. Rice, and S.R. Lorentz, Metrologia 35, 323-327 (1998). Return to Medium Background Infrared Radiometry

Medium Background Infrared (MBIR) Facility

References