Pronunciation of the German professor "Joachim Betz". He pronounced his last name himself in an TV interview with a long "e" in "Betz", so that's obviously the correct way to pronounce his name.
<a href="//commons.wikimedia.org/wiki/User:GeoTrinity" title="User:GeoTrinity">GeoTrinity (Wikimedia Commons)</a>
<span class="int-own-work" lang="en">Own work</span>