Simulations of Transverse Velocity Distributions of CR Atomic Beam Truncated by a Three-aperture Pre-collimating Slit

Transverse velocity distributions of Cr atomic beam truncated by a novel three-aperture pre-collimating slit, with and without one-dimensional transverse laser cooling, are presented. The simulations ware performed using Monte Carlo particle-optics approach, taking into account of the isotopes, distribution of longitudinal velocity and transverse divergence. The results showed that the atomic beam had a velocity distribution in the range of ±3m/s and ±1m/s, without and with laser cooling. Consequently, the transverse divergence is 0.77mrad and 0.27mrad, respectively. In addition, with an assumption that only ⁵²Cr atoms interact with the cooling laser, the existence of other isotopes will decrease the maximum value of the velocity, and increase the background.