Proximity-gated X-ray framing camera with gain uniformity

Abstract

A novel proximity gated microchannel plate (MCP) framing camera has been designed and tested. The camera system consists of two basic components with a traveling wave microstrip photocathode gated proximity focusing X-ray image tube framing and electrical control system. The voltage of the phosphor screen, the strobe pulse of the MCP and the bias voltage of the MCP are all provided by the electronic control unit. The photocathode of image-converted tube consists of Au.Four line cathodes with a width of 12 mm and an interval of 4 mm are deposited onto the illuminated side of MCP. The camera s temporal record length is ∼1.5 ns. When the cathode is applied by a pulse with full width at half maximum of 190 ps and amplitude of -2.5 kV with -100 V bias, the temporal resolution is measured to be ∼62 ps. The gain uniformity of the cathode was characterized using a short X-ray pulse produced by a laser beam focused on a copper target. The results show that the MCP gain decreases by about 28% along the pulse direction, while the gain change perpendicular to the strip direction is within 5%.