15.12.2017

Control barrack

Beam monitoring and control is carried out in a separate room (the RADEF "barrack") for safety reasons. Connecting user equipment inside the control barrack to the DUT in the cave can take up to 20 m of cabling. Several Ethernet, DB-25, DE-9 and BNC cables are already in place, but additional cables can be passed from the barrack to the cave to accommodate the users' needs.

During test runs, beam flux and fluence are measured and presented in real time; information about the beam (ion, energy, LET and range in silicon) and a history of performed runs is displayed live to the user on a giant screen (see Fig. 6 & 7). The user can start and stop runs, change the goal target fluence (and, if the target is in the irradiation chamber, translate and tilt the DUT in front of the beam) at his own will with a keyboard and a mouse. Ion species change and flux trim are more complex operations and have to be carried out by a trained RADEF operator, which will remain at all times at the disposition of the user. A log file regarding target device, ion species, flux, fluence, exposure time, collimator size and tilt angle is handed over at the end of the test campaign.

There are a few digital I/O lines that customers can use to interact with the beam monitoring system. Flux information can be provided for customer as +5V TTL pulses: the frequency of the signal corresponds to the average flux over the previous second. Thus, the flux can not be monitored in real-time but with a small delay of 1 second. Instead of doing manual calculations, customers can integrate the beam flux from start to stop into their data collection system with the help of this TTL-signal. Run starts at the rising edge and stops at the falling edge. The channel works both as a sinking and sourcing input.