First results of the sXmap cavity field emission detection system from inside a cryomodule

Field emission (FE) has been one of the limiting factors in achieving high gradients in superconducting RF cavities. While the causes for FE are mostly known (contaminants on the inner cavity surface, dust, gases adsorbed…), identifying the exact location of field emitters has been a challenge. A detection system developed by Kyoto University has been developed to address this task, the sXmap system. This diagnostic device is made of inexpensive sensor strips that wrap around the iris of a multi cell SRF cavity that sense x-rays generated by FE. In this paper we will present the results obtained from a naked 6 cell SRF cavity in a vertical test configuration, and – for the first time – the results obtained from applying the sensor strips to an SRF cavity already installed inside a cryomodule in our test cave at ORNL – SNS.