48 research outputs found
Characterization of a thinned back illuminated MIMOSA V sensor as a visible light camera
Abstract This paper reports the measurements that have been performed both in the Silicon Detector Laboratory at the University of Insubria (Como, Italy) and at the Instituto Ricerche SOlari Locarno (IRSOL) to characterize a CMOS pixel particle detector as a visible light camera. The CMOS sensor has been studied in terms of Quantum Efficiency in the visible spectrum, image blooming and reset inefficiency in saturation condition. The main goal of these measurements is to prove that this kind of particle detector can also be used as an ultra fast, 100% fill factor visible light camera in solar physics experiments
The Adaptive Gain Integrating Pixel Detector at the European XFEL
The Adaptive Gain Integrating Pixel Detector (AGIPD) is an x-ray imager,
custom designed for the European x-ray Free-Electron Laser (XFEL). It is a
fast, low noise integrating detector, with an adaptive gain amplifier per
pixel. This has an equivalent noise of less than 1 keV when detecting single
photons and, when switched into another gain state, a dynamic range of more
than 10 photons of 12 keV. In burst mode the system is able to store 352
images while running at up to 6.5 MHz, which is compatible with the 4.5 MHz
frame rate at the European XFEL. The AGIPD system was installed and
commissioned in August 2017, and successfully used for the first experiments at
the Single Particles, Clusters and Biomolecules (SPB) experimental station at
the European XFEL since September 2017. This paper describes the principal
components and performance parameters of the system.Comment: revised version after peer revie
Megapixels @ Megahertz -- The AGIPD High-Speed Cameras for the European XFEL
The European XFEL is an extremely brilliant Free Electron Laser Source with a
very demanding pulse structure: trains of 2700 X-Ray pulses are repeated at 10
Hz. The pulses inside the train are spaced by 220 ns and each one contains up
to photons of 12.4 keV, while being fs in length. AGIPD,
the Adaptive Gain Integrating Pixel Detector, is a hybrid pixel detector
developed by DESY, PSI, and the Universities of Bonn and Hamburg to cope with
these properties. It is a fast, low noise integrating detector, with single
photon sensitivity (for keV) and a large dynamic
range, up to photons at 12.4 keV. This is achieved with a charge
sensitive amplifier with 3 adaptively selected gains per pixel. 352 images can
be recorded at up to 6.5 MHz and stored in the in-pixel analogue memory and
read out between pulse trains. The core component of this detector is the AGIPD
ASIC, which consists of pixels of . Control of the ASIC's image acquisition and analogue readout is
via a command based interface. FPGA based electronic boards, controlling ASIC
operation, image digitisation and 10 GE data transmission interface AGIPD
detectors to DAQ and control systems. An AGIPD 1 Mpixel detector has been
installed at the SPB experimental station in August 2017, while a second one is
currently commissioned for the MID endstation. A larger (4 Mpixel) AGIPD
detector and one to employ Hi-Z sensor material to efficiently register photons
up to keV are currently under construction.Comment: submitted to the proceedings of the ULITIMA 2018 conference, to be
published in NIM
Development of LGAD sensors with a thin entrance window for soft X-ray detection
We show the developments carried out to improve the silicon sensor technology
for the detection of soft X-rays with hybrid X-ray detectors. An optimization
of the entrance window technology is required to improve the quantum
efficiency. The LGAD technology can be used to amplify the signal generated by
the X-rays and to increase the signal-to-noise ratio, making single photon
resolution in the soft X-ray energy range possible. In this paper, we report
first results obtained from an LGAD sensor production with an optimized thin
entrance window. Single photon detection of soft X-rays down to 452~eV has been
demonstrated from measurements, with a signal-to-noise ratio better than 20.Comment: 10 pages, 6 figure
Characterization of iLGADs using soft X-rays
Experiments at synchrotron radiation sources and X-ray Free-Electron Lasers
in the soft X-ray energy range (eV--keV) stand to benefit from the
adaptation of the hybrid silicon detector technology for low energy photons.
Inverse Low Gain Avalanche Diode (iLGAD) sensors provide an internal gain,
enhancing the signal-to-noise ratio and allowing single photon detection below
keV using hybrid detectors. In addition, an optimization of the entrance
window of these sensors enhances their quantum efficiency (QE). In this work,
the QE and the gain of a batch of different iLGAD diodes with optimized
entrance windows were characterized using soft X-rays at the
Surface/Interface:Microscopy beamline of the Swiss Light Source synchrotron.
Above eV, the QE is larger than for all sensor variations, while
the charge collection efficiency is close to . The average gain depends
on the gain layer design of the iLGADs and increases with photon energy. A
fitting procedure is introduced to extract the multiplication factor as a
function of the absorption depth of X-ray photons inside the sensors. In
particular, the multiplication factors for electron- and hole-triggered
avalanches are estimated, corresponding to photon absorption beyond or before
the gain layer, respectively.Comment: 16 pages, 8 figure
First operation of the JUNGFRAU detector in 16-memory cell mode at European XFEL
The JUNGFRAU detector is a well-established hybrid pixel detector developed at the Paul Scherrer Institut (PSI) designed for free-electron laser (FEL) applications. JUNGFRAU features a charge-integrating dynamic gain switching architecture, with three different gain stages and 75 μm pixel pitch. It is widely used at the European X-ray Free-Electron Laser (EuXFEL), a facility which produces high brilliance X-ray pulses at MHz repetition rate in the form of bursts repeating at 10 Hz. In nominal configuration, the detector utilizes only a single memory cell and supports data acquisition up to 2 kHz. This constrains the operation of the detector to a 10 Hz frame rate when combined with the pulsed train structure of the EuXFEL. When configured in so-called burst mode, the JUNGFRAU detector can acquire a series of images into sixteen memory cells at a maximum rate of around 150 kHz. This acquisition scheme is better suited for the time structure of the X-rays as well as the pump laser pulses at the EuXFEL. To ensure confidence in the use of the burst mode at EuXFEL, a wide range of measurements have been performed to characterize the detector, especially to validate the detector alibration procedures. In particular, by analyzing the detector response to varying photon intensity (so called ‘intensity scan’), special attention was given to the characterization of the transitions between gain stages. The detector was operated in both dynamic gain switching and fixed gain modes. Results of these measurements indicate difficulties in the characterization of the detector dynamic gain switching response while operated in burst mode, while no major issues have been found with fixed gain operation. Based on this outcome, fixed gain operation mode with all the memory cells was used during two experiments at EuXFEL, namely in serial femtosecond protein crystallography and Kossel lines measurements. The positive outcome of these two experiments validates the good results previously obtained, and opens the possibility for a wider usage of the detector in burst operation mode, although compromises are needed on the dynamic range