Jun 25 – 29, 2023
Ole-Johan Dahls Hus
Europe/Oslo timezone

Single photon counting pixel detector below 1 keV using LGAD sensors

Jun 27, 2023, 12:20 PM
Simula Auditorium (Ole-Johan Dahls Hus)

Simula Auditorium

Ole-Johan Dahls Hus

Oslo Science Park Gaustadalléen 23B, 0373 Oslo
Oral Detector systems Detector Systems


Filippo Baruffaldi (Paul Scherrer Insitut (Switzerland))


Soft X-rays (in the range of 200-2000 eV) are of great interest for imaging applications for a large variety of sectors. These include: imaging of organic samples, e.g., in the “water window” (between C and O, K-edges: 277 eV to 525 eV), anomalous scattering experiments around many K-edges of light elements, and L-edges of 3d transition metals (relevant to magnetic and superconducting materials). Many of the techniques performed at synchrotrons in the tender and hard X-ray regimes are currently hindered in the soft X-ray range by the lack of fast, large area, high dynamic-range detectors, sensitive to photons <2 keV [1].
To extend the application of the state-of-the art hybrid X-ray detectors to a lower energy range, PSI and FBK are developing silicon sensors based on Low Gain Avalanche Diodes (LGADs). These LGAD sensors are optimized for soft X-ray detection: they include a charge multiplication layer with a gain of ~10 in order to amplify the signal and improve the signal-to-noise ratio, combined with a thin entrance window in order to increase the quantum efficiency at lower photon energies [2]. This contribution will present tests performed in the soft X-ray regime using the developed pixelated LGAD sensors with a pixel pitch of 75 μm, bump-bonded to the EIGER single photon counting read-out chip [3]. LGAD sensors with different multiplication layer designs and a large detection area of 4×4 cm2 have been characterized at the SIM beamline at SLS (PSI, Switzerland) between 200 eV and 900 eV. Additionally, as a proof-of-principle, ptychographic scans in the soft X-ray energy range have been performed. The high dynamic range, large area, fast frame rate, and low noise of the detector outdo the results previously obtained with hybrid charge-integrating detectors (such as Mönch), and allow to achieve a high resolution, mainly limited by the size of the detector [4]. Characterization results of the sensor performances will be presented, as well as preliminary ptychographic reconstructions obtained with 500-700 eV photons.

[1] A. Hitchcock, J. Electron Spectrosc. Relat. Phenom. 200 (2015): 49-63.
[2] J. Zhang, et al., JINST 17.11 (2022).
[3] R. Dinapoli et al., NIM A 650.1 (2011): 79-83.
[4] M. Holler, et al., Nature Electronics 2.10 (2019): 464-470.

Primary authors

Aldo Mozzanica Anna Bergamaschi Antonio Liguori Dr Armin Kleibert (Paul Scherrer Insitut) Bernd Schmitt Dr Carlos Antonio Fernandes Vaz (Paul Scherrer Insitut (Switzerland)) Dr Davide Mezza (Paul Scherrer Institut) Dominic Greiffenberg Erik Fröjdh (Paul Scherrer Institut) Filippo Baruffaldi (Paul Scherrer Insitut (Switzerland)) Francesco Ficorella (Fondazione Bruno Kessler) Giovanni Paternoster (Fondazione Bruno KEssler) Jiaguo Zhang (Paul Scherrer Institut) Dr Julian Heymes (Paul Scherrer Institut) Jörg Raabe Kirsty Paton (Paul Scherrer Institut) Maria del Mar Carulla Areste Matteo Centis Vignali (FBK) Maurizio Boscardin (FBK Trento) Dr Nicholas William Phillips (Paul Scherrer Insitut (Switzerland)) Omar Hammad Ali Roberto Dinapoli (Paul Scherrer Institut) Sabina Ronchin Tim Butcher (Paul Scherrer Institute) Dr Viktoria Hinger (Paul Scherrer Institut) Xiangyu Xie (Paul Scherrer Institut)

Presentation materials