The research progress of an E//B neutral particle analyzer

An ${{E} }$//${{{B}}}$ neutral particle analyzer (NPA) has been designed and is under development at Sichuan University and Southwestern Institute of Physics. The main purpose of the ${\boldsymbol{{E}} }$//${\boldsymbol{{B}}}$ NPA is to measure the distribution function of fast ions in the HL-2A/3 tokamak. The ${\boldsymbol{{E}} }$//${\boldsymbol{{B}}}$ NPA contains three main units, i.e. the stripping unit, the analyzing unit and the detection unit. A gas stripping chamber was adopted as the stripping unit. The results of the simulations and beam tests for the stripping chamber are presented. Parallel electric and magnetic fields provided by a NdFeB permanent magnet and two parallel electric plates were designed and constructed for the analyzing unit. The calibration of the magnetic and electric fields was performed using a 50 kV electron cyclotron resonance ion source (ECRIS) platform. The detection unit consists of 32 lutetium-yttrium oxyorthosilicate (LYSO) detector modules arranged in two rows. The response functions of $\alpha$, hydrogen ions (${ \mathrm{H}}^+$, ${\mathrm{H}}^{+}_{2}$ and ${\mathrm{H}}^{+}_{3}$) and $\gamma$ for a detector module were measured with $^{241}$Am, $^{137}$Cs and $^{152}$Eu sources together with the 50 kV ECRIS platform. The overall results indicate that the designed ${\boldsymbol{{E}} }$//${\boldsymbol{{B}}}$ NPA device is capable of measuring the intensity of neutral hydrogen and deuteron atoms with energy higher than 20 keV.