Fig. 1. Structure of the gas chambers. (a) Cross-sectional view of the direct gas chamber;(b) Cross-sectional view of the reflective gas chamber

Fig. 2. Variation line of total luminous flux utilisation with parameter A

Fig. 3. (a) Light path in direct gas chamber; (b) Light path in reflective gas chamber

Fig. 4. Luminous flux of two gas chambers. (a) Detector luminous flux in direct gas chamber;(b) Detector luminous flux in reflective gas chamber

Fig. 5. (a)-(c) Optimization simulation of wall film thickness in gas chamber; (d) Detector position optimization simulation;(e) Detector luminous flux; (f) Reference detector luminous flux;(g) Ideal reflective film reference luminous flux; (h) IR gold luminous flux

Fig. 6. Detector deformation diagram analyzed by Ansys