The verification of the large dynamic range readout design for the charge detector of the very large area γ-rays space telescope.

As a successor to the DArk Matter Particle Explorer (DAMPE), the Very Large Area γ-rays Space Telescope (VLAST) is being designed to strengthen γ-ray observations and extend the cosmic ray nuclei measurements up to Zr (Z = 40) and even heavier ions. Consequently, a large dynamic range is required by the charge detector of VLAST to cover the measurements of cosmic ray particles from the proton to ultra-heavy ions. To achieve the requirements, a readout design based on the three dynodes signal extracted from the photomultiplier tube has been proposed. In addition, a prototype VLAST charge detector has been developed and tested with cosmic rays, pulse UV laser, and relativistic heavy ion beams to verify this design. The test results illustrate that the dynamic range readout design can easily cover the required dynamic range of about five orders of magnitude.