The Limadou collaboration has designed an improved version of the HEPD for the second satellite of the CSES constellation, whose launch is scheduled for 2022. The main upgrade pertains to the tracker, which will be made of Monolithic Active Pixel Sensors, never used so far in space.
To complete in time this ambitious project, a number of persons started working in 2018. The HEPD-02 tracker team includes physicist and engineers from the following research institutions:
- Department of Physics of the University of Trento
- Department of Physics of the University of Turin
- INFN, with TIFPA (Trento) and the divisions of Turin and Florence
- CNR-IFAC in Florence
- CERN in Geneva
The INFN division of Bari participates in bonding sensors to flexible printed circuits for power, control and readout.
The team has carried out the spatialisation of the MAPS technology, successfully adapting the operation mode of the ALPIDE sensor for the HEPD-02 tracker. The result is a modular and compact particle detector, made of 5 turrets, each one containing 3 stacked sensitive planes. All of 150 ALPIDE sensors are controlled and readout with a Hybrid Integrated Circuit and supported by Carbon Fiber Reinforced Plastics staves, housed in an aluminium case. The HEPD-02 tracker project demonstrates the advantages of using MAPS in space and manifesting the pioneering nature of the project for next-future larger size space missions.
The system has been tested against thermal and mechanical stresses, reproducing the operating conditions following the space launch. All tests were passed successfully and no difference in performance was observed. Although preliminary and conducted on engineering models of single staves or single turrets, these tests allowed to take the technology to readiness level 6.