4. The refrigerator of claim 1 wherein said regenerator has three layers of differing materials for providing an optimum refrigerating capacity within a temperature range of between 35 to 80 K, said layers including: a first layer on the warm side of the regenerator that includes a 200 mesh copper-bronze material extending along about 40% of the regenerators total length; a second layer adjacent said first layer that includes a 120 mesh copper-bronze material extending along about 40% of the regenerators total length, and a third layer adjacent said second layer that includes 80 to 200 mesh copper-bronze material that extends along about 20% of the regenerators total length.
4. The refrigerator of claim 1 wherein said regenerator has three layers of differing materials for providing an optimum refrigerating capacity within a temperature range of between 35 to 80 K, said layers including: a first layer on the warm side of the regenerator that includes a 200 mesh copper-bronze material extending along about 40% of the regenerators total length; a second layer adjacent said first layer that includes a 120 mesh copper-bronze material extending along about 40% of the regenerators total length, and a third layer adjacent said second layer that includes 80 to 200 mesh copper-bronze material that extends along about 20% of the regenerators total length. 5. The refrigerator of claim 4 wherein said first layer is replaced with a layer of 100 to 200 mesh stainless steel material.