MULTISTAGE PULSE TUBE REGRIGERATION CHARACTERIZATION OF THE NORTHROP GRUMMAN HIGH CAPACITY COOLER—AN UPDATE

Abstract

The characterization of a multistage Pulse Tube cycle refrigeration system has been partially performed on the Northrop Grumman High Capacity Cooler (NG HCC) cryocooler by the Air Force Research Laboratory. This cooler's design uses two pulse tube cold ends in parallel. The nominal 85 K cold end is thermally strapped to the regenerator housing of the nominal 35 K cold end in order to boost 35 K cooling capacity. The cooler was tailored to support long wave infrared (LWIR) HgCdTe focal plane arrays and their associated optical systems, but this particular refrigeration system can also support a variety of short or medium wave infrared sensing as well as high temperature superconducting electronics applications. The results are presented for both steady state and transient performance envelopes for this cooler on and off the design point of 2 Watts of cooling at 35 K and 17 Watts at 85 K. When it is off the design point the load is up to 15 Watts of cooling at “35 K” and 50 Watts on the “85 K” sides. Testin...