Calorimetric measurements of power distribution in multipole-wiggler radiation

Power density distribution in multipole-wiggler radiation was measured on the beamline BL-28 of the Photon Factory using a photocalorimetric device. The beamline had no beryllium nor graphite windows, which allowed exact comparison between measured power and calculated value using Kim's formula for undulator radiation. Although the measured density was lower by an average 20% at the peak density, it was ascertained that Kim's formula gives roughly the power density of multipole-wiggler radiation. In addition, the photocalorimetry was found to be a useful means for measuring high-power x-radiation.