IBEX is a novel mixed-mode CMOS application-specific integrated circuit (ASIC), developed at DECTRIS Ltd., dedicated to the readout of hybrid photon counting semiconductor pixel detectors. The chip ...has been strictly designed in a radiation tolerant enclosed transistor layout and is fabricated in a 110-nm CMOS technology with eight metal layers. It consists of a <inline-formula> <tex-math notation="LaTeX">256\times 256 </tex-math></inline-formula> matrix of <inline-formula> <tex-math notation="LaTeX">75\times 75\,\,\mu \text {m}^{2} </tex-math></inline-formula> pixels, which results in an overall chip size of <inline-formula> <tex-math notation="LaTeX">19.27\times 19.76 </tex-math></inline-formula> mm 2 with periphery, supply, and I/O pads included. A so-called merging mode allows for an increased pixel size of <inline-formula> <tex-math notation="LaTeX">150\times 150\,\,\mu \text {m}^{2} </tex-math></inline-formula>. The pixel readout electronics supports electrons and holes collection, and consists of a charge sensitive preamplifier with programmable gain, a shaper, and two comparators that allow for two independent energy thresholds. In the merging mode, the number of energy thresholds is increased up to four. In order to minimize the pixel-to-pixel energy threshold variation, each pixel comparator can be adjusted with a 6-bit trim digital-to-analog converter. The ASIC can operate in a continuous readout mode with two independent 16-bit counters or in a high counting range mode with a single 32-bit counter per energy threshold level. The chip features counter overflow handling and an instant retrigger technology with an adjustable retrigger time for a significantly improved high-rate counting performance. The ASIC offers a selectable external data bus width of 4, 8, or 16-bit. The count rate limit of the readout chip dc-coupled with a silicon sensor lies at around 10 Mcts/s/pix. The measurements show an electronic pixel noise of <inline-formula> <tex-math notation="LaTeX">89\,\,e^{-} </tex-math></inline-formula>rms and the detectable photon energy range between 3 and 160 keV.
Essential oils (EOs) from Moroccan ecotypes of
Artemisia herba
-
alba
,
Citrus sinensis
,
Rosmarinus officinalis
and
Thymus satureioides
and their main components were comparatively evaluated for ...their in vitro activity against the phytonematode species
Meloidogyne incognita
,
Pratylenchus vulnus
and
Xiphinema index
. Suppressiveness of drench or fumigation soil treatment with the four EOs was also investigated against
M. incognita
on tomato in potting mixes. The in vitro nematicidal activity of the main constituents of the four EOs was also determined. More than 94 % mortality of
M. incognita
juveniles occurred after a 24-h exposure to a 15 μg ml
−1
solution of
A. herba
-
alba
EO. A 100 % mortality of
X. index
females was observed at all exposure times and concentrations of all EOs except that from
C. sinensis
. Mortality of
P. vulnus
peaked at 75 % only after a 96-h permanence in the 15 μg ml
−1
solution of
R. officinalis
EO. The in vitro activity of EOs’ main components was never as high as that of the whole EOs, suggesting a synergistic action of the EO multicomponent mixture. Soil treatments with the four EOs generally resulted in a significant reduction of root-knot nematode infestation on tomato, though in an aggregate comparison of data the
A. herba
-
alba
EO was more active than the other three EOs, and fumigation treatments were more effective than application in water solution. The high nematicidal activity of most of the tested EOs and their large availability make them a potential source of new nematicide formulations.
Medicago sativa
L., alfalfa, is the most known plant species within the
Medicago
genus. The plant has been extensively studied for its content of saponins, mainly consisting of triterpene glycosides ...of medicagenic acid, possessing several biological properties including a biocidal activity on different soil microorganisms. Phytoparasitic nematodes are responsible for heavy economic damages to numerous agricultural crops and, due to their large distribution, they are among the most difficult crop pests to control. Attention on environmental safety and human and animal health has led to the progressive dismission of many synthetic formulations for the control of those pests and to the search of alternative strategies, including the use of natural metabolites from plants. Saponins from
M. sativa
may be good candidates for natural nematicide formulations, as in our in vitro studies the saponin mixtures from
M. sativa
tissues have been found effective in vitro against the virus-vector nematode
Xiphinema index
, the root-knot nematode
Meloidogyne incognita
and the potato cyst parasite,
Globodera rostochiensis
. A structure–activity relationship among saponins and related prosapogenins and sapogenin, respectively, has also been analyzed. The nematicidal efficacy differed among the three assayed nematode species,
G. rostochiensis
being the most susceptible to the active compounds from alfalfa. The in vitro results were also confirmed by experiments in potting mixes infested by
M. incognita
or
G. rostochiensis
and amended with dry top and root material from
M. sativa
, and in field trials on
M. incognita
and carrot cyst nematode
Heterodera carotae
with
M. sativa
pelleted meal. All amendments reduced root and soil population densities of target nematode species compared to non-treated and chemical controls, with a general improvement of plant growth and yield performances.
PILATUS X‐ray detectors are in operation at many synchrotron beamlines around the world. This article reports on the characterization of the new PILATUS3 detector generation at high count rates. As ...for all counting detectors, the measured intensities have to be corrected for the dead‐time of the counting mechanism at high photon fluxes. The large number of different bunch modes at these synchrotrons as well as the wide range of detector settings presents a challenge for providing accurate corrections. To avoid the intricate measurement of the count rate behaviour for every bunch mode, a Monte Carlo simulation of the counting mechanism has been implemented, which is able to predict the corrections for arbitrary bunch modes and a wide range of detector settings. This article compares the simulated results with experimental data acquired at different synchrotrons. It is found that the usage of bunch mode specific corrections based on this simulation improves the accuracy of the measured intensities by up to 40% for high photon rates and highly structured bunch modes. For less structured bunch modes, the instant retrigger technology of PILATUS3 detectors substantially reduces the dependency of the rate correction on the bunch mode. The acquired data also demonstrate that the instant retrigger technology allows for data acquisition up to 15 million photons per second per pixel.
Eiger is the next‐generation single‐photon‐counting pixel detector following the widely used Pilatus detector. Its smaller pixel size of 75 µm × 75 µm, higher frame rate of up to 22 kHz, and ...practically zero dead‐time (∼4 µs) between exposures will further various measurement methods at synchrotron sources. In this article Eiger's suitability for X‐ray photon correlation spectroscopy (XPCS) is demonstrated. By exploiting its high frame rate, complementary small‐angle X‐ray scattering (SAXS) and XPCS data are collected in parallel to determine both the structure factor and collective diffusion coefficient of a nano‐colloid suspension. For the first time, correlation times on the submillisecond time scale are accessible with a large‐area pixel detector.
Planar sensors for the upgrade of the CMS pixel detector Rohe, T.; Bean, A.; Radicci, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2011, Letnik:
650, Številka:
1
Journal Article
Recenzirano
A replacement of the present CMS pixel detector with a better performing light weight four-layer system is foreseen in 2016. In the lifetime of this new system the LHC will reach and exceed its ...nominal luminosity of 10
34
cm
−2
s
−1. Therefore the radiation hardness of all parts of the pixel system has to be reviewed.
For the construction of the much larger four-layer pixel system, the replacement of the present double sided sensors by much cheaper single sided ones is considered. However, the construction of pixel modules with such sensors is challenging due to the small geometrical distance of the sensor high voltage and the ground of the readout electronics. This small distance limits the sensor bias to about 500
V in the tested samples.
We present a simple fitting model for the pixel response to monochromatic X-rays in single photon counting pixelated detectors that takes into account the 2D effects of the charge sharing and of the ...electronic noise on the photon counting process. It is based only on geometrical and physical parameters such as the pixel size, the charge cloud size at the pixel depth and the total electronic noise of the front-end circuitry. The equations describing the pixel point spread function and the integral pulse height spectrum are derived preserving the genuine 2D nature of the charge collection process. The fitting performances of the model has been assessed on a set of experimental integral pulse height spectra measured with an IBEX photon counting ASIC bonded to a 450μm thick Silicon sensor with 75μm×75μm pixel size, irradiated with monochromatic X-rays in the energy range 6–12.4 keV, with excellent agreement between model and measurement. The actual contributions of the charge sharing and of the electronic noise are identified and estimated. As a possible consequence, the model can be used to predict precisely the behavior of photon counting detection systems as a function of the design parameters.
Summary
Suppressiveness of soil amendments with different rates of composted biowaste materials, olive pomace, municipal green wastes, sewage sludge and spent mushroom substrate, was evaluated ...against the root-knot nematode
Meloidogyne incognita
on tomato in potting mixtures. Soil amendments were applied at 0, 10, 25, 50 and 100 g kg
−1
soil, according to a randomized block design with five replications for each treatment. Sixty days after tomato transplanting, nematode population density on plant roots and in soil and root gall infestation were assessed on each root system, and plant top and root weight were also recorded. Soil pH, dry and organic matter content, total and ammoniacal nitrogen were analyzed at the same time. Olive pomace-based composts resulted in the highest nematode suppression (73–97 %, according to the rate) and significantly reduced gall formation on tomato roots. Olive-waste compost affected positively tomato growth only in combination with sheep wool wastes, but it caused phytotoxicity when mixed with chicken manure and urea. Soil amendments with composted mushroom substrate also provided a consistent nematode suppression and a significant increase of plant growth, whereas composted municipal green wastes were more suppressive and positively affected tomato growth when combined with sewage sludge. Soil chemical parameters were scarcely affected by compost amendments, as organic matter was significantly increased only by the olive pomace-derived composts and nitrogen content only at the highest rate of the five composts. Data from the experiment confirmed the potential of compost amendments for sustainable management of root-knot nematodes both in field and greenhouse container media, though their technical effectiveness and economic convenience are strictly dependent on a correct proportion and local availability of raw materials used in the composting process.
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