Nuclear Effects in Electronics and Optics

The research group "Nuclear Effects in Electronics and Optics" investigates how ionizing radiation affects electronic, optoelectronic and photonic components. The work is based on over 50 years of experience in radiation research and qualification.

It conducts radiation tests according to international standards and supports companies in qualifying and hardening their systems. The accumulated expertise also contributes to the development of innovative radiation sensor technologies. Tests are conducted both in in-house facilities and in collaboration with external partners.

Modern electrical and optical measurement systems, a precision workshop and an electronics laboratory are available for measurements. This allows most irradiation tests to be carried out entirely at the institute without additional resources from clients.

Cobalt-60 irradiation facilities

Three cobalt-60 facilities are available for gamma irradiation of electronic and optical components.

• Isotropic gamma radiation in point geometry
• Dose rates from 10 µGy/s to 1 Gy/s (3.6 rad/h to 360 krad/h)
• Special facility for low-dose-rate-tests (ELDRS)
• Doses up to 1 MGy within a few days
• Dosimetry using calibrated ionization chambers
• Option to perform in-situ/online measurements

Neutron generator

A D-T-neutron generator enables the investigation of displacement damage and the simulation of single event effects (SEE).

• Neutron energy: 14.1 MeV
• Acceleration voltage: 150 kV
• Current: 2.5 mA
• Neutron flux: up to 3×10¹⁰ neutrons/s

SEE-laser-test-systems

Two independent laser systems for testing single event effects (SEE) in both silicon and wide-bandgap semiconductors.

• Ultra-short, highly focused laser pulse generation (ps to fs, ~ 1 µm)
• Interaction via one- or two-photon absorption
• Wavelengths between 550 nm and 1550 nm
• Fully automatic scanning and measurement recording

Cryostats for irradiation at low temperatures

A cryostat enables irradiation tests over an extended temperature range and is used to study temperature-dependent radiation-induced effects.

• Temperature range during irradiation: 20 K to 350 K
• Suitable for analyzing temperature-dependent radiation-induced attenuation of optical fibers at a cobalt-60 gamma source
• Sample chamber: Ø 120 mm, height 50 mm
• Helium filling for homogeneous temperature distribution
• Capillaries Ø 2 mm for making optical or electrical contacts
• Option to perform online measurements during irradiation

Plasma- and acid-decapsulators

A plasma- and an acid-decapsulator are available for preparing electronic components for SEE testing.

Plasma-decapsulator (JIACO):

• Plasma-induced, material-friendly process
• No aggressive gases such as CF₄
• Suitable for GaAs, GaN, and other sensitive semiconductor materials
• Operation at atmospheric pressure
• Sample holder for up to six components

Acid-decapsulator (Mega Etch 7300):

• Temperature ranges: 10–250°C depending on acid medium
• Precise temperature control: ±1%
• Etching times: 1–2400 seconds, dynamically adjustable
• Variable etching volumes: 1–8 ml/min

X-ray CT

A high-resolution X-ray CT system enables low-destruction inspections of electronic components.

• Energy up to 160 keV
• Up to 2400× magnification
• 2D-resolution: 0.5 µm
• 360°-CT with 3D-reconstruction

Precision milling (ASAP-1 In-situ)

A precision milling system is available for mechanical opening and polishing of electronic components.

• Z-precision: 40 nm
• XY-table-precision: 200 nm
• Dual 4K-live-view (top-down and 45°)
• Temperature control up to 130°C
• Automatic tilt control ±5°

Total Ionizing Dose tests (TID)

Three cobalt-60 facilities are available for total ionizing dose (TID) testing. The existing infrastructure supports both simple irradiation procedures and complex test programs with additional measurements.

Features and infrastructure:

• TID-tests according to international standards (e.g. ESCC 22900)
• ISO 9001:2015-certified quality assurance for the application and characterization of radiation-induced effects in electronics and optics
• Three in-house Co-60 facilities, including one in the low-dose-rate range according to the ESCC-22900 standard
• Capability for in-situ and online measurements, step-stress sequences and specific test setups
• Active and passive testing of optical fibers, electronic components and systems
• Testing under variable boundary conditions, for example high or low temperatures or vacuum

Single Event Effect tests (SEE)

All necessary facilities and capabilities are available for the complete execution of single event effect tests, from component decapsulation and the creation of sophisticated measurement systems to irradiation using our laser systems or external facilities.

Features and infrastructure:

• SEE-tests according to international standards (e.g. ESCC 25100)
• ISO 9001:2015-certified quality assurance for the application and characterization of radiation-induced effects in electronics and optics
• Two in-house SEE laser facilities
• In-house component decapsulation using laser, plasma, wet-chemical methods or precision milling
• Active testing of electronic components and systems
• Testing under variable boundary conditions, for example high or low temperatures
• Capability for in-situ and online measurements and specific test setups

Additionally, there is regular access to external irradiation facilities for conducting SEE tests with protons and heavy ions.

Displacement Damage tests

Irradiation tests to determine displacement damage in semiconductor components are primarily conducted with protons or neutrons. Two neutron generators are available for studies on electronic and optical components.

Key technical data of the neutron generators:

• Neutron energies: 2.5 MeV and 14.1 MeV
• Neutron flux: up to 3 × 10¹⁰ neutrons/s in 4π geometry
• Flux measurement during irradiation via calibrated uranium fission chambers

In addition, the group has regular access to external irradiation facilities for performing proton irradiation.

Radiation effects in optical materials, optical fibers and fiber bragg gratings (FBG)

Ionizing radiation generates so-called color centers in optical materials. This produces electrons that occupy defects in the glass structure. These occupancy states lead to additional absorption in the band gap, causing the optical material to darken.

Studies of radiation-induced effects in optical fibers, fiber bragg gratings (FBG) and optical bulk and coating materials are conducted using specialized gamma and neutron sources as well as temperature-variable setups.

Optical materials 

The transmission properties of bulk materials are analyzed after irradiation using broadband light sources and optical spectrometers.

• Spectral measurements 200–1700 nm
• Investigation of thin layers (< 1 µm) on external electron or proton sources

Optical fibers

A precise measurement setup is available for irradiation tests on optical fibers, enabling simultaneous wavelength measurements and complete spectral analyses.

• Two discrete wavelengths + total spectrum
• Radiation-hardened and shielded measurement cables
• Reference channel for compensation of systematic influences

Fiber bragg gratings (FBG) 

FBGs are studied for radiation-induced changes in the refractive index. An interrogator with an optical 1-to-8 switch enables high-precision wavelength measurements.

• Stress-free sample holder
• Thermally stabilized measurement environment
• Detection of wavelength shifts in the pm-range