Whilst the thermal management needs of future silicon detectors are increasing, the required mass and volume minimization of all detector ancillaries gets more demanding. This requires highly ...effective active cooling in very small channels. In the context of the AIDA-2020 project, a new test stand has been developed to characterize, with unprecedented level of accuracy, boiling flows of CO2 in mini- and micro-channels with hydraulic diameter ranging from 2 down to 0.1 mm. The heat transfer coefficient and pressure drop behaviour in stainless steel tubular evaporators for saturation temperatures from ＋20 to −25 °C, mass fluxes from 1200 to 100 kg m−2 s−1 and heat fluxes from 0.5 to 3.5 W/cm2 are discussed for one diameter. In addition, high speed camera observations of CO2 flow patterns recorded on micro-structured silicon cold plates are used to help with the interpretation of the heat transfer coefficient and pressure drop trends reported.
In the future ATLAS Inner Tracker, each silicon strip module will be equipped with a switch able to separate the high voltage supply from the sensor in case the latter becomes faulty. The switch, ...placed in between the HV supply and the sensor, needs to sustain a high voltage in its OFF state, to offer a low resistance path for the sensor leakage current in the ON state, and be radiation hard up to 1.2ċ1015neq/cm2 along with other requirements. While GaN JFETs have been selected as suitable rad-hard switch, a silicon vertical HV-JFET was developed by Brookhaven National Laboratory as an alternative option. Pre-irradiation results showed the functionality of the device and proved that the silicon HV-JFET satisfied the pre-irradiation requirements for the switch. To assess its suitability after irradiation, a few p-type HV-JFETs have been neutron irradiated at Jozef Stefan Institute (JSI, Ljubljana, Slovenia). This paper reports the static characterization of these irradiated devices and the TCAD numerical simulations used to get an insight of the physics governing the post-irradiation behaviour.
Abstract
The High Luminosity LHC (HL-LHC) upgrade requires the
planned Inner Tracker (ITk) of the ATLAS detector to tolerate
extremely high radiation doses. Specifically, the innermost parts of
the ...pixel system will have to withstand radiation fluences above
1 × 10
16
n
eq
cm
-2
. Novel 3D silicon pixel
sensors offer a superior radiation tolerance compared to
conventional planar pixel sensors, and are thus excellent candidates
for the innermost parts of the ITk. This paper presents studies of
3D pixel sensors with pixel size 50 × 50 μm
2
mounted
on the RD53A prototype readout chip. Following a description of the
design and fabrication steps, Test Beam results are presented for
unirradiated as well as heavily irradiated sensors. For particles
passing at perpendicular incidence, it is shown that average
efficiencies above 96% are reached for sensors exposed to fluences
of 1 × 10
16
n
eq
cm
-2
when biased to 80 V.
In view of the LHC upgrade for the High Luminosity phase (HL-LHC), the ATLAS experiment plans to replace the Inner Detector with an all-silicon system. The n-on-p silicon technology is a promising ...candidate to achieve a large area instrumented with pixel sensors, since it is radiation hard and cost effective. The paper reports on the performance of thin 100 and 130μm n-in-p planar pixel sensors produced by FBK-CMM with active-edge technology in collaboration with LPNHE and INFN. Beam-test results are presented, with focus on the hit efficiency at the detector edge of a novel design consisting of a staggered deep trench.
In view of the LHC upgrade phase towards the High Luminosity LHC (HL-LHC), the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system.The n-on-p silicon technology is a ...promising candidate to achieve a large area instrumented with pixel sensors, since it is radiation hard and cost effective. The paper reports on the performance of thin (100 and 130μm thick) and edgeless n-on-p planar pixel sensors produced by FBK-CMM. The production featured standard 50μm×250μm pixel-pitch modules, compatible with the ATLAS FE-I4B readout chip, and small 50μm×50μm and 25μm×100μm pixel-pitch modules, compatible with the RD53A readout chip prototype. After discussing the sensor technology, an overview of 2018 testbeam results of the produced devices will be given, before and after irradiation, with a special focus on the hit efficiency at the detector edge.
In view of the LHC upgrade phases towards the High Luminosity LHC (HL-LHC), the ATLAS experiment plans to upgrade the Inner Detector with an all-silicon system. The n-on-p silicon technology is a ...promising candidate to achieve a large area instrumented with pixel sensors, since it is radiation hard and cost effective. The presentation describes the performance of novel n-in-p edgeless planar pixel sensors produced by FBK-CMM, making use of the active trench for the reduction of the dead area at the periphery of the device. After discussing the sensor technology, some feedback from preliminary results of the first beam test will be discussed.
The very high fluences (e.g. up to 2×1016 1 MeV neq/cm2) and total ionising doses (TID) of the order of 1 Grad, expected at the High Luminosity LHC (HL-LHC), impose new challenges for the design of ...effective, radiation resistant detectors. Ionising energy loss is the dominant effect for what concerns SiO2 and SiO2/Si interface radiation damage. In particular, surface damage can create a positive charge layer near the SiO2/Si interface and interface traps along the SiO2/Si interface, which strongly influence the breakdown voltage, the inter-electrode isolation and capacitance, and might also impact the charge collection properties of silicon sensors. To better understand in a comprehensive framework the complex and articulated phenomena related to surface damage at these very high doses, measurements on test structures have been carried out in this work (e.g. C–V and I–V). In particular, we have studied the properties of the SiO2 layer and of the SiO2/Si interface, using MOS capacitors, gated diodes (GD) and MOSFETs manufactured by FBK on high-resistivity n-type and p-type silicon, before and after irradiation with X-rays in the range from 50 krad(SiO2) to 20 Mrad(SiO2). Relevant parameters have been determined for all the tested devices, converging in the oxide charge density NOX, the surface generation velocity s0 and the integrated interface-trap density NIT dose-dependent values. These parameters have been extracted to both characterize the technology as a function of the dose and to be used in TCAD simulations for the surface damage effect modeling and the analysis and optimization of different classes of detectors for the next HEP experiments.
Performance of active edge pixel sensors Bomben, M.; Ducourthial, A.; Bagolini, A. ...
Journal of instrumentation,
05/2017, Letnik:
12, Številka:
5
Journal Article
Recenzirano
Odprti dostop
To cope with the High Luminosity LHC harsh conditions, the ATLAS inner tracker has to be upgraded to meet requirements in terms of radiation hardness, pile up and geometrical acceptance. The active ...edge technology allows to reduce the insensitive area at the border of the sensor thanks to an ion etched trench which avoids the crystal damage produced by the standard mechanical dicing process. Thin planar n-on-p pixel sensors with active edge have been designed and produced by LPNHE and FBK foundry. Two detector module prototypes, consisting of pixel sensors connected to FE-I4B readout chips, have been tested with beams at CERN and DESY. In this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.
For the purpose of withstanding very high radiation doses, silicon pixel sensors with a `3D' electrode geometry are being developed. Detectors of this kind are highly interesting for harch radiation ...environments such as expected in the High Luminosity LHC, but also for space physics and medical applications. In this paper, prototype sensors developed at SINTEF are presented and results from tests in a pion beam at CERN are given. These tests show that these 3D sensors perform as expected with full efficiency at bias voltages between 5 and 15V.
To cope with the harsh environment foreseen at the high luminosity conditions of HL-LHC, the ATLAS pixel detector has to be upgraded to be fully efficient with a good granularity, a maximized ...geometrical acceptance and an high read out rate. LPNHE, FBK and INFN are involved in the development of thin and edgeless planar pixel sensors in which the insensitive area at the border of the sensor is minimized thanks to the active edge technology. In this paper we report on two productions, a first one consisting of 200 μm thick n-on-p sensors with active edge, a second one composed of 100 and 130 μm thick n-on-p sensors. Those sensors have been tested on beam, both at CERN-SPS and at DESY. In terms of hit-efficiency, the first production reaches 99 % before irradiation and the second one reaches 96.3% after a fluence in excess of 1×1016neq/cm2. The performances of those two productions before and after irradiation will be presented in details.
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