Post-doctoral position : Detector Group/SEXTANTS beamline

SOLEIL is the French national synchrotron facility, located on the Saclay Plateau near Paris. It is a multi-disciplinary instrument and a research laboratory, whose mission is to run research programs using synchrotron radiation, to develop state-of-the-art instrumentation on the beamlines, and to make those available to the scientific community. SOLEIL, a unique tool for both academic research and industrial applications across a wide range of disciplines including physics, biology, chemistry etc., is used by over 5 000 researchers coming from France and abroad. The facility is a “public” company employing about 500 people, founded by the CNRS and the CEA, and partner of the Paris-Saclay University.

As part of an instrumentation upgrade program, SOLEIL is developing a new time-resolved 2D detector system dedicated to pump–probe experiments in the soft X-ray range (300 eV – 1 keV). This project is part of the “SOLEIL” targeted project of the ANR PEPR DIADEM research program which is devoted to high throughput data acquisition, automation data analysis at Synchrotron SOLEIL. 

The detector will be installed on the SEXTANTS beamline and will enable diffraction and imaging experiments with sub-nanosecond time resolution. The system combines:

  • A microchannel plate (MCP) electron multiplier for X-ray photon-to-electron conversion and amplification.
  • A fast phosphor screen for electron-to-visible photon conversion
  • A dedicated optical coupling system
  • A Timepix3 Quad hybrid pixel detector (512 × 512 pixels, 55 µm pitch) with event-driven readout and pixel-level timestamping at the nanosecond scale.

This postdoctoral project focuses on the design, optimization, integration, and commissioning of the complete detection chain.

1.Scientific and Technical Objectives :

The main objective is to design and implement a high-performance, time-resolved detector optimized for soft X-ray pump–probe experiments.

Key challenges include :

  • Modelling and optimizing detection efficiency and signal-to-noise ratio ;
  • Designing and validating the optical coupling system ;
  • Ensuring nanosecond-scale gating capability ;
  • Maximizing spatial and temporal resolution ;
  • Integrating the detector into the SOLEIL control system (TANGO) ; 

Particular emphasis will be placed on timing performance at the nanosecond scale, high-rate event-driven acquisition, and detector operation under ultra-high vacuum conditions.

2.Responsibilities :

The postdoctoral researcher will contribute to the following tasks :

  • Modelization and characterization of the detector in laboratory and beamline environments ;
  • Optimization of detector performance (gain, timing, and gating configuration) ;
  • Participate in optical system design and alignment ;
  • Develop and validate calibration procedures ;
  • Development and optimization of data processing algorithms (clustering, timing corrections, centroiding) ;
  • Lead detector commissioning and performance evaluation at the beamline ;
  • Contribute to technical documentation and scientific publications.

The project is interdisciplinary and involves close collaboration with detectors, optics, vacuum, and beamline scientists, as well as with mechanical engineering, data acquisition, and motion control teams.

The position is hosted within the Detector Group at Synchrotron SOLEIL, under the supervision of a detector scientist, and in close collaboration with the SEXTANTS beamline team.

3.Expected Profile :

Required :

  • PhD in experimental physics, detector physics, instrumentation, or a related field
  • Strong background in radiation detectors or fast timing systems
  • Data acquisition and analysis skills (Python and/or C++)
  • Ability to work in a multidisciplinary technical environment

Desirable :

  • Experience with vacuum systems and/or photon/electron detection
  • Experience with MCP-based detectors
  • Knowledge of hybrid pixel detectors
  • Experience in synchrotron or X-FEL environments

4.General conditions :

This 24-month fixed-term postdoctoral position is based at Synchrotron SOLEIL.

The selected candidate will benefit from the following conditions and opportunities :

  • Participation in the development of a state-of-the-art time-resolved soft X-ray detector ;
  • Direct involvement in beamline commissioning and advanced synchrotron experiments ;
  • Opportunity to publish in instrumentation and applied physics journals.