The Berkeley interlock for laser safety

Although the use of an access control interlock system is widely recognized as the best method of protecting a Class 3b or 4 control area, many laser users find that the interlock architecture creates functional impediments to their specific operations. We will examine some standard interlock strategies and their shortcomings, give an example of a situation where the interlock architecture itself contributed to a dangerous incident, and finally, describe a new interlock philosophy which we have been successfully using at Berkeley Laboratory for the past year.