The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector ...prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 μm. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling, and services. In this paper, the status of the DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear e + e - collider.
For the detection of secondary vertices of long lived particles containing bottom and charm quarks at the International Linear Collider (ILC), a DEPFET pixel detector is one of the technologically ...favored options. In a DEPFET sensor a MOSFET pixel detector is integrated on a sidewards depleted silicon bulk sensor, thus combining the advantages of a fully depleted silicon sensor with in-pixel amplification. DEPFET pixel matrices have been characterized in a high energy particle beam. Since the DEPFET is a very high precision device, given its large S/N (> 100) and small pixel size (36 × 22 ¿m 2 ), a DEPFET based pixel telescope consisting of 5 DEPFETs has been developed. The uncertainty on the predicted position for a device under test (DUT) positioned inside the telescope was found to be 1.4 ¿m with the existing device, due to the limited performance of two of the five DEPFET planes. A DEPFET telescope built of 5 modules equivalent to the best plane presented here, would have a track extrapolation error as low as 0.65 ¿m at the DUT plane.
The DEPFET (DEPleted Field Effect Transistor) is an active pixel particle detector with a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) integrated in each pixel, providing first ...amplification stage of readout electronics. Excellent signal over noise performance is gained this way. The DEPFET sensor will be used as a vertex detector in the Belle II experiment at SuperKEKB, electron-positron collider in Japan. The vertex detector will be composed of two layers of pixel detectors (DEPFET) and four layers of strip detectors. The DEPFET sensor requires switching and current readout circuits for its operation. These circuits have been designed as ASICs (Application Specific Integrated Circuits) in several different versions, but they provide insufficient flexibility for precise detector testing. Therefore, a test system with a flexible control cycle range and minimal noise has been designed for testing and characterizing of small detector prototypes (Minimatrices). Sensors with different design layouts and thicknesses are produced in order to evaluate and select the one with the best performance for the Belle II application. Description of the test system as well as measurement results are presented.
DEPFET is an active pixel particle detector, in which a MOSFET is integrated in each pixel, providing first amplification stage of readout electronics. Excellent signal over noise performance is ...provided this way. The DEPFET sensor is planned to be used as an inner pixel detector in the BELLE II experiment at electron-positron SuperKEKB collider in Japan. Gated operation of the DEPFET sensor is a unique function which allows making sensor insensitive for incoming radiation for defined time interval. Charge previously integrated in the DEPFET's internal gate is saved and integration can continue afterwards. The insensitive mode of the DEPFET is achieved by a suppressed clear mechanism, which clears newly generated charge in the detector bulk, but keeps charge previously stored in the internal gate by a capacitive coupling to the external gate electrode. The properties of the gated operation were evaluated with the laser beam. It was proven, that DEPFET can operate this way. The average charge selection in the insensitive mode is lower than 0.4% and the suppressed clear mechanism does not cause charge loss higher than 200 electrons. Such fast mechanism which can define a time window, where detector stops integration of new charge, can be used for example to select out noisy bunches injected in an accelerator.
DEPFET, a monolithic active pixel sensor for the ILC Velthuis, J.J.; Kohrs, R.; Mathes, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2007, Letnik:
579, Številka:
2
Journal Article
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In a DEPleted Field Effect Transistor (DEPFET) sensor a MOSFET is integrated on a sidewards depleted p-on-n silicon detector, thereby combining the advantages of a fully depleted silicon sensor with ...in-pixel amplification. A 450
μm thick DEPFET was tested in a testbeam. The
S/
N was found to be larger than 110. The position resolution is better than 5
μm. At a seed cut of 7
σ, the efficiency and purity are both close to 100%. In the readout chip a zero-suppression capability is implemented. The functionality was demonstrated using a radio-active source. The predicted impact parameter resolution of a 50
μm thick DEPFET vertex detector, is much better than required for the International Linear Collider (ILC).
Systematic effects in some semiconductor detector tests Doležal, Z.; Drásal, Z.; Kodyš, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2007, Letnik:
583, Številka:
1
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This paper deals with commonly used semiconductor detector testing methods, i.e. tests with high energy beams, lasers or radioactive beta sources. The systematic effects of the tests are analysed and ...applicability limits are determined using measurements and simulations.
The NASA Double Asteroid Redirection Test (DART) spacecraft successfully impacted the Didymos-Dimorphos binary asteroid system on 2022 September 26 UTC. We provide an update to its pre-impact mutual ...orbit and estimate the post-impact physical and orbital parameters, derived using ground-based photometric observations taken from July 2022 to February 2023. We found that the total change of the orbital period was \(-33.240 \pm 0.072\) min. (all uncertainties are 3\(\sigma\)). We obtained the eccentricity of the post-impact orbit to be \(0.028 \pm 0.016\) and the apsidal precession rate of \(7.3 \pm 2.0\) deg./day from the impact to 2022 December 2. The data taken later in December to February suggest that the eccentricity dropped close to zero or the orbit became chaotic approximately 70 days after the impact. Most of the period change took place immediately after the impact but in a few weeks following the impact it was followed by additional change of \(-27^{+19}_{-58}\) seconds or \(-19 \pm 18\) seconds (the two values depend on the approach we used to describe the evolution of the orbital period after the impact -- an exponentially decreasing angular acceleration or an assumption of a constant orbital period, which changed abruptly some time after the impact, respectively). We estimate the pre-impact Dimorphos-Didymos size ratio was \(0.223 \pm 0.012\) and the post-impact is \(0.202 \pm 0.018\), which indicates a marginally significant reduction of Dimorphos' volume by (\(9 \pm 9) \%\) as the result of the impact.
We used the times of occultations and eclipses between the components of the 65803 Didymos binary system observed in its lightcurves from 2003-2021 to estimate the orbital parameters of Dimorphos ...relative to Didymos. We employed a weighted least-squares approach and a modified Keplerian orbit model in order to accommodate the effects from non-gravitational forces such as Binary YORP that could cause a linear change in mean motion over time. We estimate that the period of the mutual orbit at the epoch 2022 September 26.0 TDB, the day of the DART impact, is \(11.9214869 \pm 0.000028\)~h (\(1\sigma\)) and that the mean motion of the orbit is changing at a rate of \((5.0\pm 1.0)\times 10^{-18}\)~rad s\(^{-2}\) \((1\sigma\)). The formal \(3\sigma\) uncertainty in orbital phase of Dimorphos during the planned Double Asteroid Redirection Test (DART) mission is \(5.4^\circ\). Observations from July to September 2022, a few months to days prior to the DART impact, should provide modest improvements to the orbital phase uncertainty and reduce it to about \(4.2^\circ\). These results, generated using a relatively simple model, are consistent with those generated using the more sophisticated model of \citet{scheirich22}, which demonstrates the reliability of our method and adds confidence to these mission-critical results.
SiLC R&D: Design, present status and perspectives Lozano, M.; Orava, R.; van Remortel, N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2007, Letnik:
579, Številka:
2
Journal Article
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Odprti dostop
This paper briefly describes the main R&D objectives that are undertaken within the international R&D collaboration SiLC aiming to build the next generation of silicon tracking devices especially in ...the case of the ILC. Firstly, motivation to use silicon detectors in the tracker is explained. Then basic aspects of the design and solutions proposed are described (sensors, front-end electronics, mechanics, alignment). First results from the lab and beam test of the front-end chips and module prototypes built are shown.
With the successful impact of the NASA DART spacecraft in the Didymos-Dimorphos binary asteroid system, we provide an initial analysis of the post-impact perturbed binary asteroid dynamics. To ...compare our simulation results with observations, we introduce a set of "observable elements" calculated using only the physical separation of the binary asteroid, rather than traditional Keplerian elements. Using numerical methods that treat the fully spin-orbit-coupled dynamics, we estimate the system's mass and the impact-induced changes in orbital velocity, semimajor axis, and eccentricity. We find that the changes to the mutual orbit depend strongly on the separation distance between Didymos and Dimorphos at the time of impact. If Dimorphos enters a tumbling state after the impact, this may be observable through changes in the system's eccentricity and orbit period. We also find that any DART-induced reshaping of Dimorphos would generally reduce the required change in orbital velocity to achieve the measured post-impact orbit period and will be assessed by the ESA Hera mission in 2027.
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