The wedge strip anode （WSA） has been widely used in 2-D positiomsensitive detectors. A circular WSA with an effective diameter of 52 mm is successfully coupled to a tripe gas electron multiplier （GEM） detector through a simple resistive layer. A spatial resolution of 440 μm （FWHM） is achieved for a 10 kVp X-ray using 1 atm Ar：CO2=70：30 gas. The simple electronics of only three channels makes it very useful in applications strongly requiring simple interface design, e.g. sealed tubes and high pressure detectors.
An event-counting thermal neutron imaging detector based on 3 mol % nattGd2O3-doped micro-channel plate （MCP） has been developed and tested. A thermal neutron imaging experiment was carried out with a low flux neutron beam. Detection efficiency of 33% was achieved with only one doped MCP. The spatial resolution of 72μ m RMS is currently limited by the readout anode. A detector with larger area and improved readout method is now being developed.
A novel thermal neutron collimator was successfully fabricated by coating the inner surface of the capillary plate （CP） with gadolinium oxide using atomic layer deposition （ALD） technology. This CP-based collimator is efficient and compact. A numerical model is presented in the paper to estimate the main performance characteristics of the collimator and to optimize the design for specific applications. According to the results of the calculation based on currently available CPs, the FWHM of the collimator’s rocking curve can be smaller than 0.15 while suppressing more than 99.9% of the incident thermal neutrons on the double wings of the curve. Such a coated CP is as thin as 1.25 mm or even thinner, providing high angular resolution with good transmission in a very limited space.
A four-rod radio frequency quadruple （RFQ） cavity has been built for the Peking University Neutron Imaging Facility （PKUNIFTY）. The rf tuning of such a cavity is important to make the field distribution flat and to tune the cavity’s resonant frequency to its operating value. Plate tuners are used to tune the RFQ, which have an effect on both the cavity frequency and field distribution. The rf performance of the RFQ and the effect of plate tuners are simulated. Based on the simulation, a code RFQTUNING is designed, which gives a fast way to tune the cavity. With the aid of the code the cavity frequency is tuned to 201.5 MHz and the flatness deviation of the field distribution is reduced to less than 5%.
