Hi John, no we do not have a prep lab. We do everything ourselves, or we ask a company do embed our standards or a university lab. We do not have a standard block, all our standards are individually mounted in little brass cups. I could send you a cup and your prep lab could mount the ThC2 in it, so it is just a single operation and there is no involvement of any contamination whatsoever, apart from the Th. That is how we proceed with other companies: We send them our little brass cups, and they send us back the purchased standards each mounted in an individual cup.