Hybrid pixel array detectors enter the low-noise regime

March 30, 2016
Photograph of the JUNGFRAU-0.4 chip and sensor on top of which a 150 µm-thick laser-drilled tungsten mask (Laser Zentrum Hannover eV, Hannover, Germany) with 28 µm-diameter holes is placed. Credit: Jungmann-Smith et al

The detector group at the Swiss Light Source at PSI has been one of the pioneers in the development of custom-made hybrid pixel array detectors (HPADs) for synchrotron applications. In a paper published recently [Jungmann-Smith et al. (2016). J. Synchrotron Rad. 23, 385-394; doi:10.1107/S1600577515023541], this group shows that it is now possible to develop HPADs with sufficient low noise to allow single-photon detection below 1 keV as well as to perform spectroscopic imaging. A commentary has also been written about the work [Graafsma (2016). J. Synchrotron Rad. 23, 383-384; doi:10.1107/S1600577516002721].

For decades, have been a limiting factor in experiments at synchrotron radiation facilities. Even though imaging detectors evolved over time, the evolution of the source always outran the evolution of the detector. This situation started to change with the introduction of the so-called hybrid pixel array detectors, which contain a pixelated readout chip custom-designed for a well-defined experiment or technique. One of the revolutionising advantages offered by this technology is that every single pixel contains all necessary electronics, including for instance counters, for X-ray detection. This massive parallelisation increased the overall efficiency of the detector by several orders of magnitude as compared with the charge-coupled-device-based system. There are now various examples of HPADs, specifically developed for X-ray experiments at storage-ring synchrotron sources, as well as various spin-off companies commercialising them.

Most of these systems are so-called photon-counting detectors, where each incoming photon is processed by the readout electronics in the pixel and individually counted. The advantage of photon counting is that electronic noise, present in any system, can be efficiently discriminated against, yielding `noise-free' detectors. An application for such low-noise systems is in energy-dispersive measurements. The researchers show in their paper that, with the use of a proper mask to shield the edge regions between pixels, very good fluorescence spectra can be obtained. This capability was subsequently used for multi-colour imaging at the SOLEIL .

The innovative aspect of the work contained in this paper does not lie in the spectroscopic results obtained as they could very well have been obtained with other detectors. But what is truly impressive is that these results were obtained with an HPAD using a standard planar diode array as sensor. This means that the system uses relatively standard and thus easy-to-manufacture components, making it possible to envision building larger and/or further-optimised systems in the near future. And with that, low-noise HPADs have entered a field formally reserved for silicon drift detectors and complementary metal-oxide semiconductor imagers.

Explore further: Clever technology decodes more information from single photons

More information: J. H. Jungmann-Smith et al. Towards hybrid pixel detectors for energy-dispersive or soft X-ray photon science, Journal of Synchrotron Radiation (2016). DOI: 10.1107/S1600577515023541

H. Graafsma. Hybrid pixel array detectors enter the low noise regime, Journal of Synchrotron Radiation (2016). DOI: 10.1107/S1600577516002721

Related Stories

Superconductors could detect superlight dark matter

February 9, 2016

(Phys.org)—Many experiments are currently searching for dark matter—the invisible substance that scientists know exists only from its gravitational effect on stars, galaxies, and other objects made of ordinary matter. ...

Tiny 'on-chip detectors' count individual photons

March 17, 2011

A team of researchers has integrated tiny detectors capable of counting individual photons on computer chips. These detectors, called "single-photon avalanche diodes (SPAD)," act like mini Geiger counters, producing a "tick" ...

Recommended for you

Probe for nanofibers has atom-scale sensitivity

January 20, 2017

Optical fibers are the backbone of modern communications, shuttling information from A to B through thin glass filaments as pulses of light. They are used extensively in telecommunications, allowing information to travel ...

Magnetic recording with light and no heat on garnet

January 19, 2017

A strong, short light pulse can record data on a magnetic layer of yttrium iron garnet doped with Co-ions. This was discovered by researchers from Radboud University in the Netherlands and Bialystok University in Poland. ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.