The absolute photon flux of Nd laser Compton scattering gamma rays was measured by using a GSO detector where the
gamma ray attenuation rate was over 99%.The maximum normalized photon flux of the gamma ray was 6.0103
(75%) photons W1 mA1 s1 at the hatch.For a storage current of 200 mA and a Nd laser input of 4.2 W at NewSUBARU,the
absolute photon flux was 5.0106 photons s1. Since gamma ray generation is possible for 12 h with a top-up mode operation of NewSUBARU, the total number of usable gamma ray photons produced continuously was 2.11011 photons per 12 h.