In this paper several age standards （including three zircon

two apatite and one sphene） have been used for Zeta determination against SRM612. No significant difference of three minerals is found. A single-weighted mean Zeta constant is given as 339.2±6.6（2σ）.The thermal neutron flux calculated from σ Φ is compared with that determined from Co foil. The ages of zircon and apatite are determined using the calibrated constant b and the track density by a dosimeter glass. The results of 27.7±0.8Ma for FCT

16.1±0.5Ma for MB

60.0±3.0Ma for TR and 30.8± 1.9Ma for Durango are consistent with the reference ages within the range of error.