For the sites below, the test procedures, test equipment, dosimetry systems are developed by  MAPRAD through dedicated cooperation agreements with facilities. These sites have been audited and are (being) used in different projects as in ESA (ITT-AO8010 and ITT-AO7482) and in H2020 (Smart-Flex) as well as by the major European space industry.

 

      1- Fraunhofer, FEP, Darmstad, for low/medium energy high intensity electron irradiations (0.6- 1.5 MeV)

The site provides uniform low energy electron beam over a large beam spot area. We have carried out a long preparation period to adapt the facility, instrumentation and tools to carry out irradiation of solar cells, optics, polymers following the procedures and requirements (unpacking/packing, handling, irradiation etc.) of ECSS/ESA. 

The characteristics of irradiation facility are; 

  • – Beam energy ranges from 0.6 to 1.5 MeV
  • – Dose rates typically from (4.5 kGy/min to 50 kGy/min, 3.e11 e/(cm2.s) and 5e12 e/(cm2.s)). The flu ences up to 1017  e/cm2 or higher can be reached 
  • – Uniformity (within 10%) beam area size approx. 12cm x 80cm
  • – Passive dosimetry with TLDs to asset the dose rate and beam spot uniformity prior to each irradiation session start

For irradiation, MAPRAD has developed complex stainless steel irradiation boxes. These boxes are in stainless steel in body (to resist to high dose rates) and aluminum in cooling plate. 

 The main features are;

  • – Samples are irradiated under inert gas (nitrogen). The oxygen contamination in the irradiation volume is continuously monitored and the data is stored,
  • – Water cooling system is realized to keep the irradiated samples at desired temperature (typically between 12-to 22 degrees) even under very high electron flux and fluence values. The water from a chiller flows through cooling plate with water temperature adjustable from 4 to 13 degrees. 
  • – The temperature of cooling plate is continuously monitored with T probes and the samples are positioned onto and kept firmly in place on the cooling plate through micro vacuum holes  
  • – The irradiation box, having a with an overall irradiation area of 10 cm x 80 cm, can accommodate solar cells, optics or polymer samples of different dimension and quantities 
  • – We have two identical boxes to be able to irradiate many number of samples during the same session. In this case the two boxes are placed on a conveyer band which moves the boxes under/out  the beam spot.

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The dosimeters and calibration phase prior to start to irradiate;

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Solar cell samples are placed in the box;

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The electron source and the box just before  to start to irradiate;

 

      2- ENEA Frascati,  UV/VUV tests (solar effect simulator)

In collaboration with ENEA-Frascati we have developed a relatively low cost, transportable UV irradiation system to irradiate a set of nano-hybrid polyamide film samples up to 3000 equivalent solar hours. The work was carried out with the support of two ESA contracts and by  SMART-FLEX project (https://www.h2020-smartflex.eu/ ).

The samples were placed on the bottom of a cylindrical irradiation chamber sealed by a quartz window. Above the window a Helios Quartz mercury lamp was placed. After degassing (vacuum at 10-5 mbar) the chamber was filled with 1.1 bar of static He, which allows a sufficient heat dissipation during irradiations to maintain the substrates temperature below 40 °C. The overall setup shown in Figure 3 includes air- and water cooling systems, UV and visible light detectors, temperature data acquisition system and a webcam for real time remote control of the main experimental parameters during the whole irradiation time. 

 

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Solar radiation spectrumThe e 200-to-400 nm wavelength interval is used as requested by ECSS-Q-ST-70-06C;

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Irradiation setup at the ENEA Research Center in Frascati;  

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Positioning of samples in the irradiation chamber. At the bottom of the chamber is the Dylux paper impressed by UV radiation(a), photo of the samples in the irradiation chamber(b)

 

      3- INFN Perugia and University of Perugia Scanning Electron Microscope (SEM) for, electron charging tests with electron energies from 15-to-30 keV

To simulate the plasma charging effects, we have proposed and built an alternative way of testing small film samples for space using 20 keV electrons from a Scanning Electron Microscope (SEM). For standard usage, the spot size of a SEM at its focal point is at the level of few nanometers, therefore a very high current density corresponding to much higher electron flux with respect to the requested by relevant ECSS/ESA standards. The equipment has been optimized to find a working point several centimeters below the focal point to obtain a large electron beam scanning surface. We have measured the flux at the surface of a sample placed at working point using gafchromic film and analyzed in 3-D image showing the beam profile obtained with parameters as requested by the test standard. This technique can be used in most SEMs with beam energies up to few tens of keV.  The details of this new approach can be found in references below.

 

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SEM scanning of Gafchromic films and their analysis with ImageJ software for 3-D profile definitions; 

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Placement of samples in SEM and monitoring of R and V values during irradiation and on test bench;

 

      4- MAPRAD laboratories, Infrared 15ns, 20W peak power pulsed laser system

This setup is particularly useful for radiation sensitivity mapping of ICs and for debugging of  instrumentation and circuitry prior to go to the irradiation site. For this purpose has been used by major research centers and industry (Tesat, ESA, IMEC, SITAEL;  proceeding by G.Magistrati et al. SEE-MAPLD2014, AMICSA13-14). 

The DUT is position on submicron precision movement system and scanned under the fixed IR beam spot (of few micron FWHM). The beam positioning, intensity and environmental paramters are controlled by dedicated software. The technical details on this setup are published (please refer to the publication list below).

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The schematics of the setup;

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Radiation sensitivity mapping of a VLSI device; 

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The picture of the pulsed IR laser setup to simulate the radiation effects on ICs; 

 

      5- INFN-LNS (Catania, Italy) at superconducting cyclotron for SEE and DD tests with heavy ions and protons 

Laboratori Nazionali del Sud (LNS)  is one of the four national laboratories of INFN. The research activity is mainly devoted to the study of structure and properties of atomic nuclei, in collaboration with researchers coming from several countries.

At LNS two particle accelerators are available: a 15 MV Tandem Van De Graaff that in the early ’80s was used for the first experiments, and a K800 Superconducting Cyclotron in full operation since 1996.

For SEE test and for proton (from few MeV to 60 MeV) irradiations, MAPRAD, developed a new dosimetry system based on silicon photomultilpliers (SIPM). Four SIPMs are located at fixed position around the DUT and a fifth one is movable  in front of DUT.  The system provides real time flux and beam spot uniformity. The irradiation setup is operating in air with all advantages that this implies.

Setup Parameters Kinetic Energy Linear Energy Projected Range
Transfer (LET)
Beam Energy Air Angle At DUT Surface In Silicon
ion [MeV] [cm] [deg.] [MeV] [MeV/(mg/cm2)] [µm]
20Ne 400 15 0 306 2.4 315
20Ne 400 15 60 306 4.8 158
40Ar 800 15 0 493 8.4 162
40Ar 800 25 60 353 20.5 51
84Kr 1680 12 0 614 33.1 68
84Kr 1680 12 45 614 46.9 48
84Kr 1680 12 60 614 66.3 34
129Xe 2580 10 0 1.158.570 54.5 80
129Xe 2580 10 45 1.158.570 77.1 57
129Xe 2580 10 60 1.158.570 109.1 40

A list of noble gases ions available at LNS  and corresponding surface Linear Energy Transfer (LET) and range values;

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Sketch of dosimetry system developed by MAPRAD;

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Dosimetery system at LNS laboratories during data taking; 

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Advantages to operate in air. Heating a DUT from back side while irradiating;

 

6- Electron-LINAC of Terni Hospital (Italy), electron beam with energies from 4 to 20 MeV;

The electron-LINAC of St. Maria Hospital (AOT) located in Terni, Italy, provides electrons of energy from 4 to 20 MeV. This e-LINAC, within a cooperation agreement and collaboration with the hospital, is prepared to irradiate semiconductors, optics, polymers, particle detectors etc. with energy range and fluxes of interest for space applications community. 

At 100 cm working distance the electron flux is about 5.107 e/(cm2.s) and can be scaled down to few particles per second at larger distances. The beam profile, electron energy and flux are measured  by semiconductor based detector (by MAPRAD) and also by Advanced Markus Chamber(AMC) provided by AOT. 

 

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Irradiation with e-LINAC head pointing horizontally;

 

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Experimental setup to irradiate and monitor the characteristics of optical components;