Temperature fields across the BES III beam pipe

During the operations of the new generation Beijing Electron and Positron Collider (BEPC II) and the Beijing Spectrometer (BES III), the inner surface of the beam pipe is subjected to high radiation heat loads. Continuous high temperatures or large temperature fluctuations can cause the main drift chamber (MDC) to detect particles abnormally. Hence, a beam pipe with a cooling system was designed, and temperature fields across the beam pipe and the MDC inner cylinder were studied experimentally and by finite-element simulations. When the inlet temperatures of the cooling oil and cooling water for the central and extended beam pipes were set to 291.4 K and 291.6 K, respectively, results showed that the inner surface temperature of the MDC inner cylinder can be controlled within the range of 292.8–293.9 K for various powers of radiation heat. This range satisfies the operating requirements of 293±2 K.