[Triumf-seminars] TRIUMF Accelerator Seminar, Tue 2018-05-29 at 13:00

TRIUMF Seminars triumf-seminars at lists.triumf.ca
Mon May 28 08:51:43 PDT 2018


Date/Time: Tue 2018-05-29 at 13:00  

Location: Auditorium  

Speaker: Christopher Wagner (Goethe-Universität Frankfurt)  

Title: Digital LLRF and control system development at FRANZ  

Abstract: The Frankfurt Neutron Source (FRANZ) is under construction at the institute for applied physics at
the Goethe-University Frankfurt. This facility will produce neutrons of variable energy with a
quasi-Maxwellian neutron spectrum of around 30 keV by the 7Li(p, n)7Be reaction. The production
target is driven by a 2 MeV intense proton beam. The accelerator consists of a coupled 4-Rod-RFQ/
IH-DTL-resonator and delivers a proton beam with up to 200 mA. As the neutron energy is
determined by the reaction kinematics, a proton beam with energy variable is necessary. Therefore a
CH-DTL rebuncher following the main accelerator adds an energy variability of ± 0.2 MeV. For the
measurement of small cross sections in a time of flight setup, a pulsed high neutron flux is
necessary, which will be delivered in the compressor mode. In this mode the proton beam is
chopped in 50 ns pulses with a repetition rate of 250 kHz behind the ion source. The resulting nine
proton bunches behind the accelerator are then merged into one compressed 1 ns bunch.
As the originally designed analog LLRF system for FRANZ is a highly specialised one, a new
versatile digital LLRF system is planned. The new flexible system could also be used in conjunction
with different experiments and accelerators being developed at the institute. Therefore, a direct
digital synthesis (DDS) based system is in development.
An essential point for the control system of FRANZ was the integration of a wide range of preexisting
hardware. Further on, the control system has to be realised with the small fiscal and
personnel budget of the institute, specifically when taking procurement and long term
maintainability into account. With consideration of these aspects, a JAVA based program was
developed. Because of the platform independence, an easy integration of devices on different
operating systems or even embedded systems is possible without special tailoring. The functional
modularisation is of great importance due to the need of downscaling to small laboratory
experiments.  

Stimulants available 15 minutes before the talk. 



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