Copper-Kapton laminate foils will be utilized as isoperibol calorimeters for pulsed energy measurements at Antares with apertures up to 1.5 m. These are volume absorbing calorimeters in which the radiation is absorbed in a layer tens of wavelengths thick, thereby reducing surface temperature and increasing damage threshold as compared to surface absorbing calorimeters. Kapton was chosen for its high absorption coefficient, 330 cm-1 at P(20) in the 10 pm band of CO2, and its useful short pulse damage threshold, 2.8 J/cm2. The copper backing integrates the absorbed heat pulse. The resultant temperature pulse is sensed by Type E thermocouples (chrome-constantan) soldered to the copper. Time vs voltage traces of the thermocouples can then be analyzed to obtain the energy absorbed. Calorimeters can be fabricated to virtually any size or shape, using photo-lithographic techniques. Utilizing single elements or several in a thermopile further expands the versatility of this technique.