18,397 research outputs found
New Superconducting Toroidal Magnet System for IAXO, the International AXion Observatory
Axions are hypothetical particles that were postulated to solve one of the
puzzles arising in the standard model of particle physics, namely the strong CP
(Charge conjugation and Parity) problem. The new International AXion
Observatory (IAXO) will incorporate the most promising solar axions detector to
date, which is designed to enhance the sensitivity to the axion-photon coupling
by one order of magnitude beyond the limits of the current state-of-the-art
detector, the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a
high-magnetic field distributed over a very large volume to convert solar
axions into X-ray photons. Inspired by the successful realization of the ATLAS
barrel and end-cap toroids, a very large superconducting toroid is currently
designed at CERN to provide the required magnetic field. This toroid will
comprise eight, one meter wide and twenty one meter long, racetrack coils. The
system is sized 5.2 m in diameter and 25 m in length. Its peak magnetic field
is 5.4 T with a stored energy of 500 MJ. The magnetic field optimization
process to arrive at maximum detector yield is described. In addition,
materials selection and their structure and sizing has been determined by force
and stress calculations. Thermal loads are estimated to size the necessary
cryogenic power and the concept of a forced flow supercritical helium based
cryogenic system is given. A quench simulation confirmed the quench protection
scheme.Comment: Accepted for publication in Adv. Cryo. Eng. (CEC/ICMC 2013 special
issue
JUNO Conceptual Design Report
The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine
the neutrino mass hierarchy using an underground liquid scintillator detector.
It is located 53 km away from both Yangjiang and Taishan Nuclear Power Plants
in Guangdong, China. The experimental hall, spanning more than 50 meters, is
under a granite mountain of over 700 m overburden. Within six years of running,
the detection of reactor antineutrinos can resolve the neutrino mass hierarchy
at a confidence level of 3-4, and determine neutrino oscillation
parameters , , and to
an accuracy of better than 1%. The JUNO detector can be also used to study
terrestrial and extra-terrestrial neutrinos and new physics beyond the Standard
Model. The central detector contains 20,000 tons liquid scintillator with an
acrylic sphere of 35 m in diameter. 17,000 508-mm diameter PMTs with high
quantum efficiency provide 75% optical coverage. The current choice of
the liquid scintillator is: linear alkyl benzene (LAB) as the solvent, plus PPO
as the scintillation fluor and a wavelength-shifter (Bis-MSB). The number of
detected photoelectrons per MeV is larger than 1,100 and the energy resolution
is expected to be 3% at 1 MeV. The calibration system is designed to deploy
multiple sources to cover the entire energy range of reactor antineutrinos, and
to achieve a full-volume position coverage inside the detector. The veto system
is used for muon detection, muon induced background study and reduction. It
consists of a Water Cherenkov detector and a Top Tracker system. The readout
system, the detector control system and the offline system insure efficient and
stable data acquisition and processing.Comment: 328 pages, 211 figure
The STM32 microcontroller based pulse intensity registration system for the neutron monitor
We present the outlines of a new microcontroller based data acquisition
system which is aimed for reliable operation in a typical cosmic ray particle
registration experiment. The system supports connection of up to 16 input
signals and ensures the following operation functionality: (1)stable monitoring
of the intensity of a digital pulse signal, or digitization of a continuous
potential level with a low time resolution (typically, in the limits of
1-100s); (2)registration of a continuous high-resolution (up to 5-10us) time
series of the intensity of input signal; (3)synchronization of registered time
series with both external (physical) or local (program-based) trigger signal;
(4)possibility of an on-the-fly change of the whole configuration of
informational system (both the combination and type of input signals, time
resolution and sum duration of the time series measurements, trigger logic,
etc) immediately in operation time through convenient communication with a
plain text message in dialog mode. In particular, the considered system is
applied now for a long-term, high precision measurement of the counting rate of
neutron signals at the NM64 type neutron supermonitor of the Tien~Shan mountain
cosmic ray station, with a real-time representation of the whole collected
dataset in a WWW database.Comment: communication at ISVHECRI 2016 and at the "10 Years Neutron Monitor
Database" NMDB Worksho
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TAO Conceptual Design Report: A Precision Measurement of the Reactor Antineutrino Spectrum with Sub-percent Energy Resolution
The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a
satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A
ton-level liquid scintillator detector will be placed at about 30 m from a core
of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be
measured with sub-percent energy resolution, to provide a reference spectrum
for future reactor neutrino experiments, and to provide a benchmark measurement
to test nuclear databases. A spherical acrylic vessel containing 2.8 ton
gadolinium-doped liquid scintillator will be viewed by 10 m^2 Silicon
Photomultipliers (SiPMs) of >50% photon detection efficiency with almost full
coverage. The photoelectron yield is about 4500 per MeV, an order higher than
any existing large-scale liquid scintillator detectors. The detector operates
at -50 degree C to lower the dark noise of SiPMs to an acceptable level. The
detector will measure about 2000 reactor antineutrinos per day, and is designed
to be well shielded from cosmogenic backgrounds and ambient radioactivities to
have about 10% background-to-signal ratio. The experiment is expected to start
operation in 2022
Experience with the Open Source based implementation for ATLAS Conditions Data Management System
Conditions Data in high energy physics experiments is frequently seen as
every data needed for reconstruction besides the event data itself. This
includes all sorts of slowly evolving data like detector alignment, calibration
and robustness, and data from detector control system. Also, every Conditions
Data Object is associated with a time interval of validity and a version.
Besides that, quite often is useful to tag collections of Conditions Data
Objects altogether. These issues have already been investigated and a data
model has been proposed and used for different implementations based in
commercial DBMSs, both at CERN and for the BaBar experiment. The special case
of the ATLAS complex trigger that requires online access to calibration and
alignment data poses new challenges that have to be met using a flexible and
customizable solution more in the line of Open Source components. Motivated by
the ATLAS challenges we have developed an alternative implementation, based in
an Open Source RDBMS. Several issues were investigated land will be described
in this paper:
-The best way to map the conditions data model into the relational database
concept considering what are foreseen as the most frequent queries.
-The clustering model best suited to address the scalability problem.
-Extensive tests were performed and will be described.
The very promising results from these tests are attracting the attention from
the HEP community and driving further developments.Comment: 8 pages, 4 figures, 3 tables, conferenc
The OLYMPUS Internal Hydrogen Target
An internal hydrogen target system was developed for the OLYMPUS experiment
at DESY, in Hamburg, Germany. The target consisted of a long, thin-walled,
tubular cell within an aluminum scattering chamber. Hydrogen entered at the
center of the cell and exited through the ends, where it was removed from the
beamline by a multistage pumping system. A cryogenic coldhead cooled the target
cell to counteract heating from the beam and increase the density of hydrogen
in the target. A fixed collimator protected the cell from synchrotron radiation
and the beam halo. A series of wakefield suppressors reduced heating from beam
wakefields. The target system was installed within the DORIS storage ring and
was successfully operated during the course of the OLYMPUS experiment in 2012.
Information on the design, fabrication, and performance of the target system is
reported.Comment: 9 pages, 13 figure
The Thin Gap Chambers database experience in test beam and preparations for ATLAS
Thin gap chambers (TGCs) are used for the muon trigger system in the forward
region of the LHC experiment ATLAS. The TGCs are expected to provide a trigger
signal within 25 ns of the bunch spacing. An extensive system test of the ATLAS
muon spectrometer has been performed in the H8 beam line at the CERN SPS during
the last few years. A relational database was used for storing the conditions
of the tests as well as the configuration of the system. This database has
provided the detector control system with the information needed for
configuration of the front end electronics. The database is used to assist the
online operation and maintenance. The same database is used to store the non
event condition and configuration parameters needed later for the offline
reconstruction software. A larger scale of the database has been produced to
support the whole TGC system. It integrates all the production, QA tests and
assembly information. A 1/12th model of the whole TGC system is currently in
use for testing the performance of this database in configuring and tracking
the condition of the system. A prototype of the database was first implemented
during the H8 test beams. This paper describes the database structure, its
interface to other systems and its operational performance.Comment: Proceedings IEEE, Nuclear Science Symposium 2005, Stockholm, Sweeden,
May 200
Technical Design Report for the PANDA Micro Vertex Detector
This document illustrates the technical layout and the expected performance of the Micro Vertex Detector (MVD) of the PANDA experiment. The MVD will detect charged particles as close as possible to the interaction zone. Design criteria and the optimisation process as well as the technical solutions chosen are discussed and the results of this process are subjected to extensive Monte Carlo physics studies. The route towards realisation of the detector is
outlined
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