Develop a robust software for calculation of Non-Ionising Energy Loss (NIEL) for a range of critical space technologies, analyse existing irradiation test data, perform irradiation tests when necessary, map defect centers generated and carry out model verification.

 

 

Non-Ionsing Energy Loss (NIEL) is an important radiation degradation-related parameter for a range of spacecraft sub-systems and components including:

 

• Solar cells.

 

• Optoelectonic devices.

 

• Bipolar transistors.

 

• Imaging instrumentation (star trackers, CCDs, photon detectors).

 

Under a previous ESA NPI activity, new NIEL models were developed that improve especially the treatment of energetic electrons. This is important for missions flying in high-intensity electron environments such as GEO Telecom missions, navigation systems (Galileo), and science missions such as JUICE. These new models, named SR-NIEL (for Screened Relativistic) utilise the Geant4 software and have recently been included in the ESA Space Environment Information System (SPENVIS).

 

It is proposed within this activity:

 

• To consolidate these models and make the necessary developments.

 

• To implement them as separate software classes within the broadly used Geant4 code as well as in space radiation engineering tools such as GRAS and MULASSIS.

 

• To extend the models by inclusion of neutron NIEL for ground testing purposes.

 

• To extend the framework to also treat heavy ions.

 

• To upgrade the existing software for further implementation of the models.

 

• To analyse existing NIEL test data.

 

• To verify the NIEL models by way of irradiation test campaigns (also employing test samples appropriate for DLTS (Deep-level transient spectroscopy) measurements). DLTS techniques will be used to establish defect concentration and their fundamental parameters.