| 51. |
- Adolfsson, J., et al.
(författare)
-
SAMPA Chip : The New 32 Channels ASIC for the ALICE TPC and MCH Upgrades
- 2017
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the test results of the second prototype of SAMPA, the ASIC designed for the upgrade of read-out front end electronics of the ALICE Time Projection Chamber (TPC) and Muon Chamber (MCH). SAMPA is made in a 130 nm CMOS technology with 1.25 V nominal voltage supply and provides 32 channels, with selectable input polarity, and three possible combinations of shaping time and sensitivity. Each channel consists of a Charge Sensitive Amplifier, a semi-Gaussian shaper and a 10-bit ADC; a Digital Signal Processor provides digital filtering and compression capability. In the second prototype run both full chip and single test blocks were fabricated, allowing block characterization and full system behaviour studies. Experimental results are here presented showing agreement with requirements for both the blocks and the full chip.
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| 52. |
- Adolfsson, Jonatan, et al.
(författare)
-
The upgrade of the ALICE TPC with GEMs and continuous readout
- 2021
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 16:3
-
Tidskriftsartikel (refereegranskat)abstract
- The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020. © 2021 CERN for the benefit of the Alice collaboration..
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| 53. |
- Afanaciev, K.G., et al.
(författare)
-
Investigation of the radiation hardness of GaAs sensors in an electron beam
- 2012
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 7:11
-
Tidskriftsartikel (refereegranskat)abstract
- A compact and finely grained sandwich calorimeter is designed to instrument the very forward region of a detector at a future e+e- collider. The calorimeter will be exposed to low energy e+e - pairs originating from beamstrahlung, resulting in absorbed doses of about one MGy per year. GaAs pad sensors interleaved with tungsten absorber plates are considered as an option for this calorimeter. Several Cr-doped GaAs sensor prototypes were produced and irradiated with 8.5-10 MeV electrons up to a dose of 1.5 MGy. The sensor performance was measured as a function of the absorbed dose.
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| 54. |
- Ahlburg, P, et al.
(författare)
-
EUDAQ - A data acquisition software framework for common beam telescopes
- 2020
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- EUDAQ is a generic data acquisition software developed for use in conjunction with common beam telescopes at charged particle beam lines. Providing high-precision reference tracks for performance studies of new sensors, beam telescopes are essential for the research and development towards future detectors for high-energy physics. As beam time is a highly limited resource, EUDAQ has been designed with reliability and ease-of-use in mind. It enables flexible integration of different independent devices under test via their specific data acquisition systems into a top-level framework. EUDAQ controls all components globally, handles the data flow centrally and synchronises and records the data streams. Over the past decade, EUDAQ has been deployed as part of a wide range of successful test beam campaigns and detector development applications. © 2020 CERN.
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| 55. |
- Alberghi, G. L., et al.
(författare)
-
Choice and characterization of photomultipliers for the new ATLAS LUCID detector
- 2016
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 11:5
-
Tidskriftsartikel (refereegranskat)abstract
- The luminosity monitor LUCID (LUminosity Cherenkov Integrating Detector) employed in the ATLAS experiment at the LHC had to be upgraded for the second run of LHC (Run 2) that started in spring 2015. The increased energy of the proton beams and the higher luminosity implied that the Photomultipliers of the original LUCID detector had to be replaced for Run 2 to cope with the more demanding conditions. This paper deals with choice and characterisation of the Photomultipliers used for the new version of LUCID.
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| 56. |
- Alme, J., et al.
(författare)
-
Correction of the baseline fluctuations in the GEM-based ALICE TPC
- 2023
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 18:11
-
Tidskriftsartikel (refereegranskat)abstract
- To operate the ALICE Time Projection Chamber in continuous mode during the Run 3 and Run 4 data-taking periods of the Large Hadron Collider, the multi-wire proportional chamber-based readout was replaced with gas-electron multipliers. As expected, the detector performance is affected by the so-called common-mode effect, which leads to significant baseline fluctuations. A detailed study of the pulse shape with the new readout has revealed that it is also affected by ion tails. Since reconstruction and data compression are performed fully online, these effects must be corrected at the hardware level in the FPGA-based common readout units. The characteristics of the common-mode effect and of the ion tail, as well as the algorithms developed for their online correction, are described in this paper. The common-mode dependencies are studied using machine-learning techniques. Toy Monte Carlo simulations are performed to illustrate the importance of online corrections and to investigate the performance of the developed algorithms. © 2023 CERN for the benefit of the Alice collaboration.
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| 57. |
- Alme, J., et al.
(författare)
-
RCU2-The ALICE TPC readout electronics consolidation for Run2
- 2013
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the solution for optimization of the ALICE TPC readout for running at full energy in the Run2 period after 2014. For the data taking with heavy ion beams an event readout rate of 400 Hz with a low dead time is envisaged for the ALICE central barrel detectors during these three years. A new component, the Readout Control Unit 2 (RCU2), is being designed to increase the present readout rate by a factor of up to 2.6. The immunity to radiation induced errors will also be significantly improved by the new design.
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| 58. |
- Alme, J., et al.
(författare)
-
Signal shapes in multiwire proportional chamber-based TPCs
- 2024
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 19:2
-
Tidskriftsartikel (refereegranskat)abstract
- A large-volume Time Projection Chamber (TPC) is the main tracking and particle identification (PID) detector of the ALICE experiment at the CERN LHC. PID in the TPC is performed via specific energy-loss measurements (dE/dx), which are derived from the average pulse-height distribution of ionization generated by charged-particle tracks traversing the TPC volume. During Runs 1 and 2, until 2018, the gas amplification stage was based on multiwire proportional chambers (MWPC). Signals from the MWPC show characteristic long negative tails after an initial positive peak due to the long ion drift times in the MWPC amplification region. This so-called ion tail can lead to a significant amplitude loss in subsequently measured signals, especially in the high-multiplicity environment of high-energy Pb-Pb collisions, which results in a degradation of the dE/dx resolution. A detailed study of the signal shapes measured with the ALICE TPC with the Ne-CO2 (90-10) and Ar-CO2 (90-10) gas mixtures is presented, and the results are compared with three-dimensional Garfield simulations. The impact of the ion tail on the PID performance is studied employing the ALICE simulation framework and the feasibility of an offline correction procedure to account for the ion tail is demonstrated. © 2024 The Author(s)
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| 59. |
- Anastasopoulos, M., et al.
(författare)
-
Multi-Grid detector for neutron spectroscopy : Results obtained on time-of-flight spectrometer CNCS
- 2017
-
Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.
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| 60. |
- Anghinolfi, F., et al.
(författare)
-
Hadron beam test of a scintillating fibre tracker system for elastic scattering and luminosity measurement in ATLAS
- 2007
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 2
-
Tidskriftsartikel (refereegranskat)abstract
- A scintillating fibre tracker is proposed to measure elastic proton scattering at very small angles in the ATLAS experiment at CERN. The tracker will be located in so-called Roman Pot units at a distance of 240 m on each side of the ATLAS interaction point. An initial validation of the design choices was achieved in a beam test at DESY in a relatively low energy electron beam and using slow off-the-shelf electronics. Here we report on the results from a second beam test experiment carried out at CERN, where new detector prototypes were tested in a high energy hadron beam, using the first version of the custom designed front-end electronics. With a spatial resolution of 25 mu m an adequate tracking performance was obtained, under conditions which are similar to the situation at the LHC. In addition, the alignment method using so-called overlap detectors was studied and shown to have the expected precision.
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