XRF (X-ray fluorescence spectrometer) detector is used to receive X-ray and convert it into measurable or observable quantity. At present, the most commonly used detectors are gas flow proportional counter, closed proportional counter, scintillation counter and semiconductor detector used in X-ray fluorescence energy spectrum analysis.

(1) Gas flow proportional counter. It is mainly used to detect X-rays with wavelength of 0.2 ~ 1.5nm, usually with thickness of 2 ~ 6nm μ m. The aluminized polyester film is used as the window material and filled with the mixture of 90% argon and 10% methane. As the window is so thin, the detector is easy to leak, so fresh gas should be supplied continuously, and the gas flow rate is generally 1.6 ~ 3.2l/min. In recent years, in order to detect ultra soft X-ray (wavelength up to 1 ~ 10nm), the window is often used 1 μ The content of methane can be as high as 100% or helium can be used. The energy resolution of the gas flow proportional counter is second only to that of the semiconductor detector, and the resolution of the feka I line is 10% ~ 20%, which is 2 ~ 3 times of that of the scintillation counter. Its counting resolution time is similar to that of scintillation counter, and it is suitable for counting up to 105 ~ 106 CPS (i.e. pulse / s). The proportional counter filled with argon or krypton has a large escape peak. When the window of gas flow proportional counter is damaged or the anode wire is stained, it can be replaced or cleaned.

(2) Closed proportional counter. According to the different gases of helium, neon, argon, krypton and xenon, the X-ray with the wavelength of 0.03 ~ 0.4nm can be detected.

(3) Scintillation counter. It is mainly used to detect X-rays with wavelength of 0.01 ~ 0.3nm, and can record counts up to 106 ~ 107cps. It consists of a Thallium activated NaI crystal sealed in a beryllium window and a photomultiplier tube. It has a relatively complete absorption capacity for high energy X-rays, but has a poor detection efficiency for low energy X-rays below 6kev. This is just complementary to the detection efficiency of gas flow proportional counter. Therefore, at present, some instrument manufacturers connect a flow gas proportional counter in front of the scintillation counter. Low energy soft X-rays are mainly received by the flow gas proportional counter, while non received high energy hard X-rays are received by the scintillation counter. This series device can effectively improve the counting intensity of elements from chromium to copper.

(4) Li drift Si and Li drift Ge detectors [denoted as Si (LI) and Ge (LI) semiconductor detectors]. Its advantages are high resolution, good linear response, long life and stable performance. Its noise can reach tens of electron volts at room temperature. When used in X-ray measurement, it must be operated at low temperature under the protection of liquid nitrogen. Therefore, it is limited in application.

(5) Si PIN detector and SDD detector are new industrial technologies in recent years. They have high resolution and high stability. They can be used stably for several years or even decades without external cooling and inflation