A new magnetometer with Cs vapor in the spin exchange relaxation free(SERF) regime is described.Cs has a higher saturated vapor pressure than other alkali metals;so cesium SERF magnetometer is particularly attractive in applications that require lower power dissipation.Four factors affect atomic transverse relaxations in the SERF magnetometer,including collisions and diffusions among Cs,N2 and He,laser pumping and detecting processes;the buffer gas pressure of He that affects the relaxation is calculated an...