To extend the physics reach of the Large Hadron Collider (LHC), upgrades to the accelerator are planned which will increase the peak luminosity by a factor 5–10. To cope with the increased occupancy ...and radiation damage, the ATLAS experiment plans to introduce an all-silicon inner tracker with the high luminosity upgrade (HL-LHC). To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Upgrade Planar Pixel Sensor (PPS) R&D Project was established. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edges to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. The Insertable b-layer (IBL) is the first upgrade project within the ATLAS experiment and will employ a new detector layer consisting of silicon pixel sensors, which were improved and prototyped in the framework of the planar pixel sensor R&D project. A special focus of this paper is the status of the development and testing of planar n-in-n pixel sensors including the quality control of the on-going series production and postprocessing of sensor wafers. A high yield of produced planar sensor wafers and FE-I4 double chip sensors after first steps of post-processing including under bump metallization and dicing is observed.
► Prototypes of irradiated planar n-in-n sensors have been successfully tested under laboratory conditions. ► A quality assurance programme on the series production of planar sensors for the IBL has started. ► A high yield of double chip sensors during the series production is observed which are compatible to the specifications to this detector component.
The innermost part of the tracking detector of the ATLAS experiment consists mainly of planar n+-in-n silicon pixel sensors. During the phase-0 upgrade, the Insertable B-Layer (IBL) was installed ...closest to the beam pipe. Its pixels are arranged with a pitch of 250 μm×50μm with a rectangular shaped n+ implantation. Based on this design modified pixel designs have been developed in Dortmund.
Six of these new pixel designs are arranged in structures of ten columns and were placed beside structures with the standard design on one sensor. Because of a special guard ring design, each structure can be powered and investigated separately. Several of these sensors were bump bonded to FE-I4 read-out chips. One of these modules was irradiated with reactor neutrons up to a fluence of 5×1015neqcm−2.
This contribution presents important sensor characteristics, charge collection determined with radioactive sources and hit efficiency measurements, performed in laboratory and test beam, of this irradiated device. It is shown that the new modified designs perform similar or better than the IBL standard design in terms of charge collection and tracking efficiency, at the cost of a slightly increased leakage current.
The COBRA demonstrator at the LNGS underground laboratory Ebert, J.; Fritts, M.; Gehre, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2016, Letnik:
807
Journal Article
Recenzirano
Odprti dostop
The COBRA demonstrator, a prototype for a large-scale experiment searching for neutrinoless double beta-decay, was built at the underground laboratory Laboratori Nazionali del Gran Sasso (LNGS) in ...Italy. It consists of an array of 64 monolithic, calorimetric CdZnTe semiconductor detectors with a coplanar-grid design and a total mass of 380g. It is used to investigate the experimental challenges faced when operating CdZnTe detectors in low-background mode, to identify potential background sources and to show the long-term stability of the detectors. The first data-taking period started in 2011 with a subset of the detectors, while the demonstrator was completed in November 2013. To date, more than 250kgd of data have been collected. This paper describes the technical details of the experimental setup and the hardware components.
Power dissipation studies on planar n+-in-n pixel sensors Klingenberg, R.; Altenheiner, S.; Bryan, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2016, Letnik:
831
Journal Article
Recenzirano
Research and development laboratory measurements of non-irradiated and irradiated planar n+-in-n pixel sensor structures are systematically investigated to determine the power dissipation of those ...sensors. Measurements were taken at different operation temperatures, sensor bias voltages, bulk thicknesses, sensor areas, and irradiation fluences. For planar n+-in-n pixel sensors irradiated to HL-LHC fluences of some 1016neqcm−2 a power dissipation area density of (126±8)mWcm–2 at a temperature of −25°C and at an operation voltage of 800V is derived for small sensors with an area of about 0.7cm2. For large sensors as planned for the ATLAS phase-II upgrade a power dissipation of 100mWcm–2 is expected.
To avoid geometrical inefficiencies in the ATLAS pixel detector, the concept of shingling is used up to now in the barrel section. For the upgrades of ATLAS, it is desired to avoid this as it ...increases the volume and material budget of the pixel layers and complicates the cooling.
A direct planar edge-to-edge arrangement of pixel modules has not been possible in the past due to about
1100
μ
m
of inactive edge composed of approximately
600
μ
m
of guard rings and
500
μ
m
of safety margin. In this work, the safety margin and guard rings of ATLAS SingleChip sensors were cut at different positions using a standard diamond dicing saw and irradiated afterwards to explore the breakdown behaviour and the leakage current development.
It is found that the inactive edge can be reduced to about
400
μ
m
of guard rings with almost no reduction in pre-irradiation testability and leakage current performance. This is in particular important for the insertable b-layer upgrade of ATLAS (IBL) where inactive edges of less than
450
μ
m
width are required.
Scribe–cleave–passivate (SCP) slim edge technology for silicon sensors Fadeyev, V.; Sadrozinski, H.F.-W.; Ely, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
731
Journal Article
Recenzirano
We are pursuing scribe–cleave–passivate (SCP) technology of making “slim edge” sensors. Such sensors have only a minimal amount of inactive peripheral region, which benefits construction of ...large-area tracker and imaging systems. Key application steps of this method are surface scribing, cleaving, and passivation of the resulting sidewall. We are working on developing both the technology and physical understanding of the processed devices performance. In this paper we begin by reviewing the manufacturing options of SCP technology. Then we show new results regarding the technology automation and device physics performance. The latter includes charge collection efficiency near the edge and radiation hardness study. We also report on the status of devices processed at the request of the RD50 collaborators.
The COBRA collaboration searches for neutrinoless double beta-decay (0νββ-decay) using CdZnTe semiconductor detectors with a coplanar-grid readout and a surrounding guard-ring structure. The ...operation of the COBRA demonstrator at the Gran Sasso underground laboratory (LNGS) indicates that alpha-induced lateral surface events are the dominant source of background events. By instrumenting the guard-ring electrode it is possible to suppress this type of background. In laboratory measurements this method achieved a suppression factor of alpha-induced lateral surface events of 5300+2660−1380, while retaining (85.3 ±0.1%) of gamma events occurring in the entire detector volume. This suppression is superior to the pulse-shape analysis methods used so far in COBRA by three orders of magnitude.
In order to meet the requirements of the High Luminosity LHC (HL-LHC), it will be necessary to replace the current tracker of the ATLAS experiment. Therefore, a new all-silicon tracking detector is ...being developed, the so-called Inner Tracker (ITk). The use of quad chip modules is intended in its pixel region. These modules consist of a silicon sensor that forms a unit along with four read-out chips. The current ATLAS pixel detector consists of planar n-in-n silicon pixel sensors. Similar sensors and four FE-I4 read-out chips were assembled to first prototypes of planar n-in-n quad modules. The main focus of the investigation of these modules was the region between the read-out chips, especially the central area between all four read-out chips. There are special pixel cells placed on the sensor which cover the gap between the read-out chips. This contribution focuses on the characterization of a non-irradiated device, including important sensor characteristics, charge collection determined with radioactive sources as well as hit efficiency measurements, performed in the laboratory and at testbeams. In addition, first laboratory results of an irradiated device are presented.
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