A compact minicryostat has been well adapted on the hard x-ray microprobe ID22 of the European Synchrotron Radiation Facility. For variable low-temperature investigations, its special technical design provides precise scanning microscopy and allows easy access for multiple detection modes. Based on x-ray excited optical luminescence technique on the micrometer scale, details of the equipment, its temperature calibration, and typical results are described. Data collections from InAs quantum heterostructures support the excellent thermal performance of the novel cryogenic device.Special thanks are due to Michele Soulier and Yves Dabin for the design of the mechanical interface used on the sample stage. The authors are also grateful to Remi Tucoulou as well as Isabelle Letard for their useful help.Peer reviewe