Gotthard-II is a charge-integrating microstrip detector developed for experiments and diagnostics at free-electron lasers using hard X-rays of 5 keV–20 keV. Thanks to its excellent single photon sensitivity, large dynamic range as well as... more
Gotthard-II is a charge-integrating microstrip detector developed for experiments and diagnostics at free-electron lasers using hard X-rays of 5 keV–20 keV. Thanks to its excellent single photon sensitivity, large dynamic range as well as high frame rate of 4.5 MHz in burst mode, its potential scientific applications include X-ray absorption/emission spectroscopy, hard X-ray high resolution single-shot spectrometry (HiREX), beam diagnostics, as well as veto signal generation for pixel detectors. The Gotthard-II ASIC has been designed and fabricated using UMC-110 nm technology. The final ASIC design and performance in terms of noise, linearity, dynamic range, coupling between channels and speed will be discussed in the paper. In addition, a first measurement of an X-ray absorption spectrum of a standard copper sample has been done. The performance of the Gotthard-II in an experiment using energy dispersive X-rays has been demonstrated.
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Within the CALICE collaboration†, several concepts for the hadronic calorimeter of a future linear collider detector are studied. After having demonstrated the capabilities of the measurement methods in “physics prototypes” the focus now... more
Within the CALICE collaboration†, several concepts for the hadronic calorimeter of a future linear collider detector are studied. After having demonstrated the capabilities of the measurement methods in “physics prototypes” the focus now lies on improving their implementation in “engineering prototypes”, that are scalable to the full linear collider detector. The Analog Hadron Calorimeter (AHCAL) concept is a sampling calorimeter of tungsten or steel absorber plates and plastic scintillator tiles read out by silicon photo multipliers (SiPMs) as active material. The frontend ASICs are integrated into the active layers of the calorimeter and are allowing the prototype to be equipped with different types of scintillator tiles as well as SiPMs. Four layers have been equipped with a novel design of scintillator tile wrapped in reflecting foil and directly coupled to a SiPM manufactured by Ketek. The blue sensitive SiPM has 2304 pixels, an average gain of 6×106 electrons and an average da...
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Due to the complexity of the underlying pathomechanism, in vivo mouse lung-disease models continue to be of great importance in preclinical respiratory research. Longitudinal studies following the cause of a disease or evaluating... more
Due to the complexity of the underlying pathomechanism, in vivo mouse lung-disease models continue to be of great importance in preclinical respiratory research. Longitudinal studies following the cause of a disease or evaluating treatment efficacy are of particular interest but challenging due to the small size of the mouse lung and the fast breathing rate. Synchrotron-based in-line phase-contrast computed tomography imaging has been successfully applied in lung research in various applications, but mostly at dose levels that forbid longitudinal in vivo studies. Here, the novel charge-integrating hybrid detector MÖNCH is presented, which enables imaging of mouse lungs at a pixel size of 25 µm, in less than 10 s and with an entrance dose of about 70 mGy, which therefore will allow longitudinal lung disease studies to be performed in mouse models.
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X-ray free-electron lasers (XFELs) enable novel experiments because of their high peak brilliance and femtosecond pulse duration. However, non-superconducting XFELs offer repetition rates of only 10-120 Hz, placing significant demands on... more
X-ray free-electron lasers (XFELs) enable novel experiments because of their high peak brilliance and femtosecond pulse duration. However, non-superconducting XFELs offer repetition rates of only 10-120 Hz, placing significant demands on beam time and sample consumption. We describe serial femtosecond crystallography experiments performed at the European XFEL, the first MHz repetition rate XFEL, delivering 1.128 MHz X-ray pulse trains at 10 Hz. Given the short spacing between pulses, damage caused by shock waves launched by one XFEL pulse on sample probed by subsequent pulses is a concern. To investigate this issue, we collected data from lysozyme microcrystals, exposed to a ~15 μm XFEL beam. Under these conditions, data quality is independent of whether the first or subsequent pulses of the train were used for data collection. We also analyzed a mixture of microcrystals of jack bean proteins, from which the structure of native, magnesium-containing concanavalin A was determined.
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MÖNCH is a 25 µm-pitch charge-integrating detector aimed at exploring the limits of current hybrid silicon detector technology. The small pixel size makes it ideal for high-resolution imaging. With an electronic noise of about 110 eV... more
MÖNCH is a 25 µm-pitch charge-integrating detector aimed at exploring the limits of current hybrid silicon detector technology. The small pixel size makes it ideal for high-resolution imaging. With an electronic noise of about 110 eV r.m.s., it opens new perspectives for many synchrotron applications where currently the detector is the limiting factor,e.g.inelastic X-ray scattering, Laue diffraction and soft X-ray or high-resolution color imaging. Due to the small pixel pitch, the charge cloud generated by absorbed X-rays is shared between neighboring pixels for most of the photons. Therefore, at low photon fluxes, interpolation algorithms can be applied to determine the absorption position of each photon with a resolution of the order of 1 µm. In this work, the characterization results of one of the MÖNCH prototypes are presented under low-flux conditions. A custom interpolation algorithm is described and applied to the data to obtain high-resolution images. Images obtained in grat...
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Within RAPSODI1 novel types of Silicon Photo-Multiplier (SiPM) from different suppliers were investigated. The main parameters: dark count rate, amplification, dynamic range, quantum detection efficiency and optical cross-talk have been... more
Within RAPSODI1 novel types of Silicon Photo-Multiplier (SiPM) from different suppliers were investigated. The main parameters: dark count rate, amplification, dynamic range, quantum detection efficiency and optical cross-talk have been studied to qualify the detectors. Results demonstrate the possibility to apply this detection technology to intense photon fluxes detection as well as to low plurality ones. Characterization protocol for a
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ABSTRACT We present the characterization of a multi-pixel detector (SiPM, Hamamatsu) in the presence of dark-count and cross-talk effects. Our description yields a self-consistent calibration of the device, based on the light under... more
ABSTRACT We present the characterization of a multi-pixel detector (SiPM, Hamamatsu) in the presence of dark-count and cross-talk effects. Our description yields a self-consistent calibration of the device, based on the light under investigation, which is used to evaluate shot-by-shot detected-photon numbers including dark-counts and cross-talk. The analysis allows us to reliably reconstruct the detected-photons statistics of different light states by taking into account the modifications introduced by detector features. Finally we quantify photon-number correlations in bipartite states and use the data to produce conditional states: only if dark-count and cross-talk effects can be neglected, the experimental results match theory.
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ABSTRACT