Lifetime Measurement of Cold Atoms in an Integrating Sphere

We present an experimental measurement of the lifetime of the cold ⁸⁷Rb atoms in an integrating sphere. The atoms are cooled by the diffuse light which is generated by the diffuse reflection of laser beams in the integrating sphere. Our result shows that the lifetime is primarily determined by the free fall of the cold ⁸⁷Rb atoms, and its half-life can reach 40ms, which is suitable for many experiments, especially for a cold atom clock.