The Penetrating particle Analyzer (PAN) is a compact magnetic spectrometer with relatively low power budget allowing it to be used in deep space and interplanetary missions for cosmic rays, solar physics and space weather studies. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles in the range between 100 MeV/n and 10 GeV/n. The device consists of permanent magnet sections, silicon strip detectors, scintillating detectors and silicon pixel detectors. At the current stage of the R&D, the first smaller prototype, called Mini.PAN, was built. Mini.PAN is designed to demonstrate the capabilities and performance of the instrument concept. The key component of Mini.PAN is the fine-pitched and thin silicon strip detectors custom designed for measuring the bending of the charged particle in the spectrometer. These detectors are 150 $\mu$m thick layer with 25 $\mu$m readout to achieve a position resolution of a few $\mu$m and provide the optimal momentum resolution within the effective energy range.

In 2021 and 2022 several beam tests were performed at CERN with various types of particles and of different energies to demonstrate the quality and performance of different subdetectors as well as the integrated Mini.PAN. In this contribution the design of the demonstrator is described, and preliminary results from the beam tests are presented.