The High-energy Stereoscopic System (H.E.S.S.) is an array of atmospheric Cherenkov telescopes dedicated to GeV-TeV γ ray astronomy. Four 12 meter diameter telescopes (CT) are currently in operation ...and a fifth 28 meter diameter telescope (LCT) should be completed by 2011. This will lower the system's energy threshold in stereoscopy down to ≈50 GeV. Concurrently, the LCT will also be used to detect monoscopic lower energy showers without a coincident detection on the smaller telescopes. This is made possible thanks to the higher sensitivity and the faster electronics of the LCT. But lowering the L1 trigger conditions on the LCT results in a larger number of spurious background detections the reduction of which motivates the second level trigger system of the LCT. An efficient L2 selection algorithm was designed based on intensive off line simulations of air shower images from different background events and their morphological differences as seen by the LCT. The present contribution reports on the flexible and reconfigurable hardware solution designed for the L2 trigger, and on the real-time implementation of the proposed L2 algorithm.
HESS is an array of atmospheric Cherenkov telescopes dedicated to GeV–TeV
γ-ray astronomy. The original array has been in operation since the beginning of 2004. It is composed of four 12-m diameter ...telescopes. The installation of a fifth 28-m diameter telescope is being completed. This telescope will operate both in stereoscopic mode and in monoscopic mode
i.e. without a coincident detection on the smaller telescopes. A second-level trigger system is needed to suppress spurious triggers of the 28-m telescope when operated in monoscopic mode. This paper gives the motivation and principle of the second-level trigger. The principle of operation is illustrated by an example algorithm. The hardware implementation of the second level trigger system of HESS phase 2 is described and its expected performances are then evaluated.
The tradeoff between readout speed, granularity, power consumption, material budget and radiation hardness has balanced in favor of CMOS Active Pixel Sensor (APS) technology for the pixel detector of ...the incoming ALICE Muon Forward Tracker experiment. In order to avoid pile-up effects in HL-LHC, the classical rolling shutter readout system of CMOS APS, dedicated to charged particle tracking, should be improved to overcome the readout speed limit induced by the row by row signal processing. The proposed solution is based on a novel pixel design including the sensing diode, the analogue signal amplification, a correlated double sampling circuit and an auto-zeroed differential discriminator, all within a 25 μm pitch square pixel. The resulting Rolling Shutter Binary Pixel architecture (RSBPix) allows more than two rows being readout simultaneously. This paper presents a RSBPix prototype designed and fabricated in a 0.18 μm CMOS Image Sensor process. A description of the ASIC architecture is provided, followed by the detailed test results from laboratory measurements. First achievements of a low temporal and fixed pattern noise, fast readout speed (160 ns per row) digital pixel are shown.
In July 2012, as the four ground-based gamma-ray telescopes of the H.E.S.S. (High Energy Stereoscopic System) array reached their tenth year of operation in Khomas Highlands, Namibia, a fifth ...telescope took its first data as part of the system. This new Cherenkov detector, comprising a 614.5m2 reflector with a highly pixelized camera in its focal plane, improves the sensitivity of the current array by a factor two and extends its energy domain down to a few tens of GeV.
The present part I of the paper gives a detailed description of the fifth H.E.S.S. telescope׳s camera, presenting the details of both the hardware and the software, emphasizing the main improvements as compared to previous H.E.S.S. camera technology.
We studied the capacity of adrenal medullary transplant to restore the deficits of GABAergic and dopaminergic neurons in mice injected with quinolinic acid (QA), using an open field test as well as ...pharmacological and immunohistochemical techniques. We analysed behavioural traits—total locomotor activity, peripheral and central activities, grooming, leaning and rearing in the QA-lesioned mice and mice that had undergone adrenal medulla (AM) transplantation. We found that the adrenal transplant recovered a loss of GABAergic neurons. It reduced QA-induced hyperactivity in locomotion and improved emotional indices. In addition, immunohistochemical studies of catecholaminergic markers—tyrosine hydroxylase (TH), dopamine (DA) and neuronal vesicular monoamine transporter type 2- and a single post-trial injection of tetrabenazine (TBZ; 5 mg/kg) indicated that catecholamines-synthesising chromaffin cells in the AM grafts were also involved in the beneficial effects. A likely interpretation of this behavioural pattern of results is that adrenal medullary transplants set into play an interaction between GABAergic and DAergic factors. Our results may contribute to the clarification of the beneficial effects of AM transplants in striatal function.
Laser monitoring system for the CMS lead tungstate crystal calorimeter Anfreville, M.; Bailleux, D.; Bard, J.P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2008, Letnik:
594, Številka:
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We report on the multiple wavelength laser monitoring system designed for the compact muon solenoid (CMS) lead tungstate crystal calorimeter. Results are presented for the test-beam performance of ...the system designed to achieve ⩽0.2% relative optical transmittance inter-calibration for 75
848 lead tungstate crystals. The system cycles continuously over the calorimeter to follow each crystal's evolution under the irradiation and recovery periods foreseen during operation at the LHC.
Immunohistochemical and behavioral techniques were used to study the effects of adrenal medulla grafts, implanted in striatum after bilateral kainic acid (KA) lesions of this structure, on the open ...field behavior of mice. KA-induced behavioral changes in leaning, grooming and locomotor activity of the open field test were significantly improved after grafting of the adrenal medulla, and in some respects, fully restored. Immunohistochemical identification showed that grafts contained neuron-like cells with a tyrosine hydroxylase (TH), phenylethanolamine
N-methyltransferase, gamma-aminobutyric acid (GABA), choline acetyltransferase (ChAT), and enkephalin-like immunostainings. A likely interpretation of this complex pattern of results is that adrenal medullary grafts may restore the deficits of GABAergic neurons which in turn reverse the abnormalities in emotionality and locomotion. Neurobiologically, these behavioral improvements probably involve GABAergic and catecholaminergic factors of adrenal medulla grafts, although other neuroactive substances, such as acetylcholine and enkephalins, cannot be excluded.
A study of the effect of Ginkgo biloba extract (EGb 761) has shown enhancing effects on training in adult and aged Swiss mice. An analysis of inbred mice has confirmed this sensitivity to EGb 761, ...but depending on the strains, with different effects at different ages. The most interesting results are related to improvements in performances observed with aged mice of the
DBA
2J
strain. The results obtained with inbred strains in the study of the mossy fibers of the hippocampus make it possible to suggest a link between the improvements in training and the histological structure of the hippocampus. This possibility, which can be confirmed by further studies, is presented here.
Clinical and experimental evidence suggests a relationship between two important pathological traits, epilepsy and anxiety, that might involve the GABA
A receptor. To demonstrate a direct link, ...anxiogenic responses induced by a benzodiazepine receptor ligand have been assessed in mice selected for their sensitivity to epilepsy. The results provided evidence for a link between seizuring and anxiety, but showed no direct involvement of GABA
A receptors.
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