Field integrated pulse tube cryocooler with SADA II compatibility

1. A unitary pulse tube expander configured as a drop-in replacement for a Stirling expander in a SADA II coldfinger, said pulse tube expander comprising:

a) a pulse tube having first and second ends;

b) a regenerator positioned about said pulse tube;

c) a regenerator sleeve placed in about said regenerator, said regenerator sleeve having an outer diameter; and

d) a cold cap positioned over said pulse tube second end,

whereby said regenerator sleeve outer diameter is sized for removable attachment of said pulse tube expander to a SADA II coldfinger.

2. The pulse tube expander of claim 1 , and further comprising a hot heat exchanger mounted adjacent said pulse tube first end and a cold heat exchanger mounted adjacent said pulse tube second end.

3. The pulse tube expander of claim 1 wherein said regenerator comprises a plurality of stacked mesh discs.

4. The pulse tube expander of claim 1 wherein said pulse tube, said regenerator and said regenerator sleeve are in coaxial alignment with one another.

5. A method of shipping a pulse tube expander and SADA II coldfinger to a Dewar/sensor manufacturer, said method comprising the steps of:

a) providing a unitary pulse tube expander having a regenerator sleeve and cold end cap sized to removably attach to a SADA II coldfinger;

b) removably attaching said unitary pulse tube expander to said SADA II coldfinger and thereby closing the interior of said pulse tube expander off to the ambient;

c) charging said unitary pulse tube expander and SADA II coldfinger with an inert gas; and

d) shipping said unitary pulse tube expander and said SADA II coldfinger to a Dewar/sensor manufacturer.

6. The method of claim 5 , and further comprising the steps of:

a) removing said shipped SADA II coldfinger from said pulse tube expander; and

b) attaching said pulse tube expander to another SADA II coldfinger which has been previously attached to a Dewar assembly.