Excess carrier photoconductance decay lifetime, measured under small perturbation conditions imposed on steady-state generation, offers an attractive and parameter free alternative to quasi-steady-state photoconductance, QSSPC. A recent version of this technique referred to as QSS-mu PCD is based on microwave reflectance PCD monitoring. For this technique, it is critically important to maintain a mono-exponential decay over a large range of steady-state light intensity. Toward that goal we present QSS-mu PCD with stringent quality of decay control, QDC. The quality of decay parameter, QD (ideally QD=1) measures the direction and magnitude of departures from an ideal exponential transient and enables tuning toward an optimal range of experimental variables, both apparatus and wafer dependent, whereby QD is within 1 +/- Delta where Delta defines the QDC limits. Within QDC limits, the small perturbation effective decay lifetime. tau(eff.d), enables accurate determination of important silicon PV parameters, up to about 25 suns, including J(0) and the steady-state lifetime, tau(eff.ss). Two J(0) procedures are compared. The ingenious analytical procedure adopted from Basore and Hansen (1990)[2] enables direct determination of J(0). The second J(0) procedure uses integration of tau(eff.d) over illumination intensity. The results are self-consistent and they show excellent correlation with Sinton QSSPC results. (C) 2012 Elsevier B.V. All rights reserved.