The ATLAS detector has been designed for operation at CERN's Large Hadron Collider. ATLAS includes a complex system of liquid argon calorimeters. The electronics for amplifying, shaping, sampling, ...pipelining, and digitizing the calorimeter signals is implemented on the Front End Boards (FEBs). This paper describes the design, implementation and production of the FEBs and presents measurement results from testing performed at several stages during the production process.
The results of two irradiation tests on 14 single-frequency 1310-nm grating-outcoupled surface-emitting semiconductor lasers that have been exposed to ionizing radiation using 200-MeV/c proton beams ...are reported. Twelve powered lasers survived a total radiation dose of up to 22.3 Mrad. One of the two not-powered lasers survived a total dose of 1.5 Mrad. The other failed after an integrated dose of 22.3 Mrad, suggesting that annealing may play an important role in laser performance during irradiation. The static and dynamic characteristics of the lasers after irradiation indicate the suitability of these lasers for medical, space, and accelerator-based nuclear and particle physics applications.
The time reconstruction performance of the ATLAS electromagnetic calorimeter readout is studied. The contribution of the electronics to the time resolution is estimated to be about 20
ps, thus ...demonstrating the possibility of achieving a small constant term in the time resolution for particles. The resolution to electromagnetic showers produced by an electron beam is also measured. After correction for the effects due to the calorimeter geometry, a 100
ps constant term is found for a typical cell.
R&D towards cryogenic optical links Christiansen, M; Galea, R; Gong, D ...
Journal of instrumentation,
12/2010, Letnik:
5, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A number of critical active and passive components of optical links have been tested at 77 K or lower temperatures, demonstrating potential development of optical links operating inside the liquid ...argon time projection chamber (LArTPC) detector cryostat. A ring oscillator, individual MOSFETs, and a high speed 16:1 serializer fabricated in a commercial 0.25-{micro}m silicon-on-sapphire CMOS technology continued to function from room temperature to 4.2 K, 15 K, and 77 K respectively. Three types of laser diodes lase from room temperature to 77 K. Optical fibers and optical connectors exhibited minute attenuation changes from room temperature to 77 K.
The ATLAS detector has been built to study the reactions produced by the Large Hadron Collider (LHC). ATLAS includes a system of liquid argon calorimeters for energy measurements. The electronics for ...amplifying, shaping, sampling, pipelining, and digitizing the calorimeter signals is implemented on a set of front-end electronic boards. The front-end boards are installed in crates mounted between the calorimeters, where they will be subjected to significant levels of radiation during LHC operation. As a result, all components used on the front-end boards had to be subjected to an extensive set of radiation qualification tests. This paper describes radiationtolerant designs, radiation testing, and radiation qualification of the front-end readout system for the ATLAS liquid argon calorimeters.
The Liquid Argon calorimeters play a central role in the ATLAS (A Toroidal LHC Apparatus) experiment. The environment at the Large Hadron Collider (LHC) imposes strong constraints on the detectors ...readout systems. In order to achieve very high precision measurements, the detector signals are processed at various stages before reaching the Data Acquisition system (DAQ). Signals from the calorimeter cells are received by on-detector Front End Boards (FEB), which sample the incoming pulse every 25ns and digitize it at a trigger rate of up to 75~kHz. Off-detector Read Out Driver (ROD) boards further process the data and send reconstructed quantities to the DAQ while also monitoring the data quality. In this paper, the ATLAS Liquid Argon electronics chain is described first, followed by a detailed description of the off-detector readout system. Finally, the tests performed on the system are summarized.
Abstract
The Phase-I trigger readout electronics upgrade of the ATLAS
Liquid Argon calorimeters enhances the
physics reach of the experiment during the upcoming operation at
increasing Large Hadron ...Collider luminosities.
The new system, installed during the second Large Hadron Collider Long Shutdown,
increases the trigger readout granularity by up to a factor of ten
as well as its precision and range.
Consequently, the background rejection at trigger level is improved
through enhanced filtering algorithms utilizing the additional information
for topological discrimination of electromagnetic and hadronic shower shapes.
This paper presents the final designs of the new electronic elements,
their custom electronic devices, the procedures
used to validate their proper functioning, and the performance achieved
during the commissioning of this system.
We have measured the branching fraction and photon energy spectrum for the radiative penguin process b-->s gamma. We find Beta(b-->s gamma) = (3.21+/-0.43+/-0.27(+0.18)(-0.10))x10(-4), where the ...errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, <E( gamma)> = 2.346+/-0.032+/-0.011 GeV, and <E(2)(gamma)>-<E(gamma)>(2) = 0.0226+/-0.0066+/-0.0020 GeV(2), where the errors are statistical and systematic. From the first moment, we obtain (in the modified minimal subtraction renormalization scheme, to order 1/M(3)(B) and beta(0)alpha(2)(s)) the heavy quark effective theory parameter Lambda = 0.35+/-0.08+/-0.10 GeV.
The radiation tolerance of three multimode optical fibres has been investigated to establish their suitability for the use in the front-end data links of the ATLAS experiment. Both gamma and neutron ...irradiation studies are reported. A step-index fibre with a pure silica core showed an induced attenuation of
∼0.05
dB/
m
at
330
kGy(
Si)
and
1×10
15
n(1
MeV
Si
)/
cm
2
and is suitable for use with the inner detector links which operate at 40–
80
Mb/
s
. A graded-index fibre with a predominantly germanium-doped core exhibits an induced attenuation of
∼0.1
dB/
m
at
800
Gy(
Si)
and
2×10
13
n(1
MeV
Si
)/
cm
2
and is suitable for the calorimeter links which operate at
1.6
Gb/
s
. Measurements of the dose rate dependence of the induced attenuation indicate that the attenuation in ATLAS will be lower.
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