Hard X-Ray Collimation System at the T-15MD Tokamak

The Hard X-Ray collimation system was installed at the T-15MD tokamak (major radius of R = 1.48 m, minor radius of a = 0.67 m, elongation of k = 1.7–1.9, triangularity of δ = 0.3–0.4, toroidal magnetic field of BT = 2 T, plasma current of up to Ip = 2 MA, and discharge duration of up to 30 s) to provide the possibility of measuring the spatial and temporal evolution of runaway electron beams. The diagnostic is based on LaBr3(Ce) scintillation detectors, witch provides energy spectrum measurements for energies form 0.3 to 10 MeV. Monte Carlo simulation of the shielding efficiency in the GEANT4 environment showed that the collimator provides 2° field of view (FOV). Horizontal and vertical FOV movement along the plasma cross-section is arranged by a rotating base and screw support elements. An algorithm for processing the signals from the scintillation detectors with a graphical user interface and data visualization is used for reconstruction of the spectra. The results of testing the detector in a laboratory setup and in preliminary experiments carried out with the T-15MD tokamak in which runaway electrons beams were generated are presented.