Varex Imaging Nederland in Doetinchem develops, produces, and supplies components for medical and industrial X-ray equipment and has an interesting internship position.

Internship/ Stage Next-Generation X-Ray sensors

Objective:
Conduct a feasibility study for a new Automatic Exposure Control (AEC) amplifier front-end compatible with ionization chamber technology in medical X-ray systems. The goal is to analyze technical requirements, explore potential architectures, and deliver a well-supported recommendation for next steps toward implementation.

Background:
The AEC system ensures that an X-ray system delivers the optimal radiation dose for high-quality imaging while minimizing patient exposure. X-ray intensity is measured using an ionization chamber (or optionally solid-state sensors) positioned near the detector. These sensors produce extremely small currents proportional to the dose rate. The AEC amplifier converts these picoamp-level currents into a proportional signal that the X-ray generator uses to terminate exposure precisely.

Current solutions rely on aging components and face challenges such as leakage currents, noise, and compliance with medical standards. A next-generation design must address these issues while remaining cost-effective and reliable.

Scope:

• Define functional and performance requirements (noise, leakage, dynamic range).
• Investigate candidate architectures (e.g., switched-capacitor vs. transimpedance).
• Perform basic simulations or calculations to validate feasibility.
• Build a working proof of concept to demonstrate core functionality.
• Solid-state sensor compatibility: optional, considered only if time permits.
• Deliverables: feasibility report with design recommendations and risk assessment.

Deliverables:

• Requirements specification document.
• Comparative analysis of amplifier architectures.
• Simulation results or analytical validation of selected concept.
• Working proof of concept demonstrating key functionality.
• Final feasibility report with recommendations for prototype development.

Learning Goals:

• Master techniques for measuring and conditioning ultra-low currents (picoampere to nanoampere range).
• Apply analog electronics principles under real-world constraints such as leakage and noise.
• Gain experience in concept validation, simulation, and technical reporting.
• Understand compliance considerations for medical electronics (IEC 60601).

Technical Challenge:

• Accurate measurement and conditioning of extremely low-level currents.
• Minimizing leakage and noise through circuit design and PCB layout strategies.
• Ensuring stability and reliability in high-impedance environments.

Level:

• Graduating with a bachelor's degree in Electrical Engineering.
• Student at the Technical University of Electrical Engineering.

Additional Information:

• Expected period: February until July 2026.
• We offer market-based compensation.
• Work will mainly be carried out at the location in Doetinchem.

Varex is located in a new, comfortable, and spacious building, designed for the future and equipped with the latest developments, creating a fantastic working environment. The building is centrally located with excellent access routes and within walking distance of the train and bus station.

To apply, please use the application form on the website.