Syrinx project: first results with a 640 kJ LTD accelerator

This paper presents the first results achieved on a LTD module built at the CEG (France-DGA) in collaboration with the HCEI (Russia-Tomsk). The main purpose of this work is to evaluate the LTD concept in term of efficiency, cost, reliability, etc. for applications to multimegajoule inductive storage generators. The concept of LTD is based on an inductive voltage adder at the level of the capacitor. The size of components (capacitor, switch, magnetic core, ...) allows to obtain a very compact system running in air. The stage includes 2 capacitors HEAFELY (75 kV-5.651 /spl mu/F), 2 multichannel multigap coaxial switches (MMCS), a magnetic core in classical transformer steel and a cavity in oil. The vacuum line is modular stage by stage. The alignment and the electrical contact is obtained by inside compression rods. The short circuit load includes 4 current loops and a Rogowski coil. The charging circuit in air allows to charge 20 stages (40 capacitors). The trigger circuit is based on a MMCS with 40 ouput lines (for 40 switches). The dynamic premagnetizing generator drives 20 ouput lines (1.2 kA, 60 /spl mu/s each). The results of experiments and numerical simulations on short circuit give : quarterperiod : 980 ns; peak current: 930 kA; 11.3 /spl mu/F, 35 nH, 25 m/spl Omega/ per stage. The first results on a 15 stages line on a POS show good behaviour of the interfaces during the opening. Those experiments must be completed by tests on more inductive load with a 20 stages line.