In the present work, the determinations of k0 and Q0 for 74Se, 113In, 186W and 191Ir targets were performed. The irradiations were conducted near the core of the IEA-R1 4.5MW swimming-pool nuclear research reactor of the Instituto de Pesquisas Energ??ticas e Nucleares (IPEN-CNEN/SP ??? Nuclear and Energy Research Institute), in S??o Paulo, Brazil. The irradiation position was chosen where the neutron spectrum shape parameter ?? is very close to zero. For this reason, the correction to be applied for the determination of Q0 is very close to one, thus improving the accuracy of the results. For each experiment, two irradiations were carried out in sequence: the first one with bare samples and the second with a cadmium cover around the samples. All partial uncertainties were considered, applying the covariance matrix methodology. The final results were compared with the literature.Conselho Nacional de Desenvolvimento Cient??fico e Tecnol??gico (CNPq)CNPq: PQ-302747/2014-1