Temperature controlled radiation gage

Claim 1

IN A GAMMA RADIATION GAGE ADAPTED TO USE WITHIN AN ENCLOSURE MAINTAINED AT A RELATIVELY HIGH TEMPERATURE LEVEL, A GAMMA RADIATION SOURCE PROVIDED WITH A GAMMA RADIATION DETECTOR IN LINE WITH SAID SOURCE BUT SEPARATED THEREFROM BY A SPACE RESERVED FOR THE RECEPTION OF MATERIAL A CONDITION OF WHICH IT IS DESIRED TO EVALUATE AS A FUNCTION OF RADIATION ABSORPTION, A GAMMA RADIATIONPERMEABLE JACKET HERMETICALLY ENCLOSING SAID GAMMA RADIATION DETECTOR AND DEFINING THEREWITH A COOLING RESERVOIR OF A PRESELECTED CAPACITY SUCH AS TO ABSORB HEAT TRANSMITTED TO SAID DETECTOR FROM SAID ENCLOSURE AS LATENT HEAT OF VAPORIZATION OF A LIQUID COOLANT SUPPLIED TO SAID COOLING RESERVOIR, SAID LIQUID COOLANT BEING A SATURATED HY DROCARBON CONTAINING UP TO TWO CARBON ATOMS HAVING FREE VALENCE BONDS SUBSTANTIALLY COMPLETELY SATURATED WITH FLUORINE PLUS ONE OTHER HALOGEN ELEMENT FROM THE GROUP CONSISTING OF CHLORINE AND BROMINE, SAID COOLANT BEING SUBSTANTIALLY NON-ABSORPTIVE OF GAMMA RADIATION EMITTED BY SAID SOURCE AND STABLE UNDER GAMMA IRRADIATION, AND COOLANT CONDENSING MEANS IN COMMUNICATION WITH SAID COOLING RESERVOIR RECEIVING VAPORIZED COOLANT AND RECYCLING CONDENSED COOLANT TO SAID RESERVOIR