Helmut Wiedemann Story
How Helmut came to SLAC
Accelerator labs in Europe and the US have had exchanges of personnel for more than 75 years. This included scientists from the US spending a year or more at CERN, DESY, and other European labs and scientists from European labs doing the same at US facilities. One of the earliest such events involved DESY in Hamburg and the Cambridge Electron Accelerator (CEA) at Harvard University. Both were building 5-6 GeV alternating gradient (AG) strong focusing electron synchrotrons. In 1959 DESY was in early stages of designing their facility while CEA was finalizing its design. This was in the early days of AG facilities so there was little experience.
Although DESY and CEA were competitors, these two labs had very good relations, so the Director of DESY (Willibald Jentschke) arranged with the Director of CEA (Stan Livingston) to send Gustav-Adolf Voss, one of his bright young staff members, to Harvard for a year to learn what he can. Voss came to the US in 1959 with his wife and two children. Their travel expenses and salary were paid by DESY with the understanding that they would return to DESY after one year. Voss turned out to contribute so much to the CEA program that, at the end of the year, Livingston offered him a job as head of the CEA accelerator team. By this time Voss and his family were very happy with their experience in the US so Voss wanted to accept the job. DESY director Jentnschke was very disappointed to learn this but could not prevent it from happening.
This experience however led DESY to adopt a new rule, called Lex Voss. This required future DESY staff being sent to US labs at DESY expense to sign an agreement that they would reimburse DESY for the funds DESY paid to support their stay in the US if they did not return to DESY for at least several years after their US visit.
Helmut came under this rule and signed such an agreement when he came to SLAC as a one year visitor from DESY. He contributed so much to the colliding beam program at SLAC that Richter offered him a job at SLAC. Helmut wanted to accept this offer but did not want to reimburse DESY for the many thousands of dollars that DESY paid in support of his visit. When Richter learned this he arranged to pay for this and Helmut stayed at SLAC.