Low-Temp cryogenic Refrigeration Schematic

Looking for refrigeration cryogenic Engeneer to create schematic calculation for project involving cryotherapy chambers, cascade refrigeration systems low temperature gases as R507, R449A, R23, R170 to reach extreme low temperatures below −80°C for our cryotherapy chamber... (Budget: $3000 - $5000 USD, Jobs: Mechanical Engineering, Process Engineering, Refrigerated Goods, Thermal Analysis, Thermodynamics)