Single photon imaging X-ray spectrometers using low noise current preamplifiers with dc voltage bias

The new generation of X-ray detectors, the hybrid pixel area detectors or `pixel detectors', is based on direct detection and single-photon counting processes. A large linearity range, high dynamic and extremely low noise leading to an unprecedented high signal-to-noise ratio, fast readout time (high frame rates) and an electronic shutter are among their intrinsic characteristics which render them very attractive. First used on synchrotron beamlines, these detectors are also promising in the laboratory, in particular for pump-probe or quasi-static experiments and accurate electron density measurements, as explained in this paper. An original laboratory diffractometer made from a Nonius Mach3 goniometer equipped with an Incoatec Mo microsource and an XPAD pixel area detector has been developed at the CRM2 laboratory. MoKα accurate charge density quality data up to 1.21 Å−1resolution have been collected on a sodium nitroprusside crystal using this home-made diffractometer. Data quality for charge density analysis based on multipolar modelling are discussed in this paper. Deformation electron densities are compared to those already published (based on data collected with CCD APEXII and CAD4 diffractometers).

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High-Resolution High-Count-Rate X-ray Spectroscopy with State-of-the-Art Silicon Detectors

Journal of Synchrotron Radiation ◽

10.1107/s0909049597014052 ◽

1998 ◽

Vol 5 (3) ◽

pp. 268-274 ◽

Cited By ~ 8

Author(s):

L. Strüder ◽

C. Fiorini ◽

E. Gatti ◽

R. Hartmann ◽

P. Holl ◽

...

Keyword(s):

Count Rate ◽

Room Temperature ◽

Single Photon ◽

Low Noise ◽

Light Sources ◽

X Rays ◽

X Ray ◽

Synchrotron Light ◽

On Chip ◽

Synchrotron Light Sources

For the European X-ray multi-mirror (XMM) satellite mission and the German X-ray satellite ABRIXAS, fully depleted pn-CCDs have been fabricated, enabling high-speed low-noise position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2. At 150 K it has a noise of 4 e− r.m.s., with a readout time of the total focal plane array of 4 ms. The maximum count rate for single-photon counting was 105 counts s−1 under flat-field conditions. In the integration mode more than 109 counts s−1 can be detected at 6 keV. Its position resolution is of the order of 100 µm. The quantum efficiency is higher than 90% from carbon K X-rays (277 eV) up to 10 keV. New cylindrical silicon drift detectors have been designed, fabricated and tested. They comprise an integrated on-chip amplifier system with continuous reset, on-chip voltage divider, electron accumulation layer stabilizer, large area, homogeneous radiation entrance window and a drain for surface-generated leakage current. At count rates as high as 2 × 106 counts cm−2 s−1, they still show excellent spectroscopic behaviour at room-temperature operation in single-photon detection mode. The energy resolution at room temperature is 220 eV at 6 keV X-ray energy and 140 eV at 253 K, being achieved with Peltier coolers. These systems were operated at synchrotron light sources (ESRF, HASYLAB and NLS) as X-ray fluorescence spectrometers in scanning electron microscopes and as ultra low noise photodiodes. The operation of a multi-channel silicon drift detector system is already foreseen at synchrotron light sources for X-ray holography experiments. All systems are fabricated in planar technology having the detector and amplifiers monolithically integrated on high-resistivity silicon.

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Single photon imaging X-ray spectrometers

IEEE Transactions on Applied Superconductivity ◽

10.1109/77.783741 ◽

1999 ◽

Vol 9 (2) ◽

pp. 3326-3329 ◽

Cited By ~ 8

Author(s):

K. Segall ◽

C.M. Wilson ◽

L. Li ◽

A.K. Davies ◽

R. Lathrop ◽

...

Keyword(s):

Single Photon ◽

X Ray ◽

Photon Imaging

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High-Resolution X-ray Spectroscopy Close to Room Temperature

Microscopy and Microanalysis ◽

10.1017/s1431927698980606 ◽

1998 ◽

Vol 4 (6) ◽

pp. 622-631 ◽

Cited By ~ 51

Author(s):

L. Strüder ◽

N. Meidinger ◽

D. Stotter ◽

J. Kemmer ◽

P. Lechner ◽

...

Keyword(s):

High Resolution ◽

Count Rate ◽

High Speed ◽

Room Temperature ◽

Single Photon ◽

Low Noise ◽

Detector System ◽

Wide Field ◽

X Rays ◽

X Ray

Originally designed as position-sensitive detectors for particle tracking, silicon drift detectors (SDDs) are now used for high-count rate X-ray spectroscopy, operating close to room temperature. Their low-capacitance read-node concept places them among the fastest high-resolution detector systems. They have been used in a new spectrum of experiments in the wide field of X-ray spectroscopy: fluorescent analysis, diffrac-tometry, materials analysis, and synchrotron experiments such as X-ray holography and element imaging in scanning electron microscopes. The fact that the detector system can be used at room temperature with good spectroscopic performance and at −10°C with excellent energy resolution, avoiding liquid nitrogen for cooling and high-quality vacuum, guarantees a large variety of new applications, independent of the laboratory environment. A brief description of the device principles is followed by basics on low noise amplification. The performance results of a complete detector system are presented as well as some dedicated applications already realized, including use in a surface mapping instrument and use of a “mini-spectrometer” for the analysis of works of art. Fully depleted pn-charge-coupled devices (pn-CCDs) have been fabricated for the European X-ray Multi-Mirror mission (XMM) and the German X-ray satellite ABRIXAS, enabling high-speed, low-noise, position-resolving X-ray spectroscopy. The detector was designed and fabricated with a homogeneously sensitive area of 36 cm2. At −70°C it has a noise of 4 e- rms, with a readout time of the total focal plane array of 4 msec. The maximum count rate for single photon counting was 105 cps under flat field conditions. In the integration mode, more than 109 cps can be detected at 6 keV. Its position resolution is on the order of 100 μm. The quantum efficiency is higher than 90%, ranging from carbon K X-rays (277 eV) up to 10 keV.

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Characterization of Chromium Compensated GaAs Sensors with the Charge-Integrating JUNGFRAU Readout Chip by Means of a Highly Collimated Pencil Beam

Sensors ◽

10.3390/s21041550 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1550

Author(s):

Dominic Greiffenberg ◽

Marie Andrä ◽

Rebecca Barten ◽

Anna Bergamaschi ◽

Martin Brückner ◽

...

Keyword(s):

Low Noise ◽

State University ◽

Noise Performance ◽

X Ray ◽

A Value ◽

Resolution Capability ◽

Sensor Properties ◽

Pixel Pitch ◽

Lower Noise

Chromium compensated GaAs or GaAs:Cr sensors provided by the Tomsk State University (Russia) were characterized using the low noise, charge integrating readout chip JUNGFRAU with a pixel pitch of 75 × 75 µm2 regarding its application as an X-ray detector at synchrotrons sources or FELs. Sensor properties such as dark current, resistivity, noise performance, spectral resolution capability and charge transport properties were measured and compared with results from a previous batch of GaAs:Cr sensors which were produced from wafers obtained from a different supplier. The properties of the sample from the later batch of sensors from 2017 show a resistivity of 1.69 × 109 Ω/cm, which is 47% higher compared to the previous batch from 2016. Moreover, its noise performance is 14% lower with a value of (101.65 ± 0.04) e− ENC and the resolution of a monochromatic 60 keV photo peak is significantly improved by 38% to a FWHM of 4.3%. Likely, this is due to improvements in charge collection, lower noise, and more homogeneous effective pixel size. In a previous work, a hole lifetime of 1.4 ns for GaAs:Cr sensors was determined for the sensors of the 2016 sensor batch, explaining the so-called “crater effect” which describes the occurrence of negative signals in the pixels around a pixel with a photon hit due to the missing hole contribution to the overall signal causing an incomplete signal induction. In this publication, the “crater effect” is further elaborated by measuring GaAs:Cr sensors using the sensors from 2017. The hole lifetime of these sensors was 2.5 ns. A focused photon beam was used to illuminate well defined positions along the pixels in order to corroborate the findings from the previous work and to further characterize the consequences of the “crater effect” on the detector operation.

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