[en] The ATLAS extension of the Argonne heavy-ion booster accelerator consists of three cryostat sections. The first cryostat contains six High Beta (β = 0.1c) resonators, a design which has been used since 1978 at Argonne. The second cryostat has three β = 0.1c resonators and three β = 0.16c resonators. The third cryostat holds six of the β = 0.16c resonators. These cryostats have been (on-line) in their accelerating position, with all systems installed and operational since February 1985. This paper will discuss the off-line tests of the β = 0.16 resonators, and the operating experience with the ATLAS linac, and particularly the new resonators, during our initial shake down. It will also cover the performance of the β = 0.16c resonators