We present a method for simultaneous measurement of magnetic field and inertia by using a hybrid optical pumping of 39 K and 85 Rb atoms. The K atoms are directly pumped by a laser and the two species interact with each other by spin exchange and the average magnetization of each other. A simultaneous-measurement model of magnetic field and inertia is proposed based on the coupled spin ensemble. By solving the K-Rb Bloch equation analytically and numerically, we find that the steady-state response for K, Rb transverse polarizations is linearly dependent on magnetic field and inertial rotation rate. The optimal bias magnetic field, suppression of the disturbance magnetic field in the signal, density ratio of K/Rb, and temperature of the cell are carefully analyzed to make the measurement model precise.

Recently, heat treatment between 250 °C and 500 °C has been attempted to improve quality factor (Q) of superconducting radio-frequency cavities at FNAL and KEK. Experiments of such medium temperature (mid-T) bake with furnaces have also been carried out at IHEP. Firstly, over ten 1.3 GHz 1-cell cavities were treated with different temperatures at a small furnace, which all demonstrated improvement of Q and anti-Q-slope phenomenon. The average quality factor has reached 3.6×10 10 when the gradient is 16 MV/m，while the highest Q is 4.9×10 10 @16MV/m; the maximum gradients of these 1-cell cavities are between 25.1 and 36.9 MV/m. Then, the recipe of mid-T furnace bake at 300 °C for 3 hours has been applied to six 1.3 GHz 9-cell cavities at a new big furnace, which have all shown higher Q and anti-Q-slope at medium field (16~24 MV/m). The average quality factor has reached 3.8×10 10 when the gradient is 16 MV/m. The maximum gradients of the 9-cell cavities are between 22.7 and 26.5 MV/m.

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