3,356 research outputs found
The liquid Argon TPC: a powerful detector for future neutrino experiments and proton decay searches
We discuss the possibility of new generation neutrino and astroparticle
physics experiments exploiting the liquid Argon Time Projection Chamber (LAr
TPC) technique, following a graded strategy that envisions applications with
increasing detector masses (from 100 ton to 100 kton). The ICARUS R&D program
has already demonstrated that the technology is mature with the test of the
T600 detector at surface. Since 2003 we have been working with the conceptual
design of a very large LAr TPC with a mass of 50-100 kton to be built by
employing a monolithic technology based on the use of industrial, large volume,
cryogenic tankers developed by the petro-chemical industry. Such a detector, if
realized, would be an ideal match for a Super Beam, Beta Beam or Neutrino
Factory, covering a broad physics program that includes the detection of
atmospheric, solar and supernova neutrinos, and searches for proton decay, in
addition to the rich accelerator neutrino physics program. A "test module" with
a mass of the order of 10 kton operated underground or at shallow depth would
represent a necessary milestone towards the realization of the 100 kton
detector, with an interesting physics program on its own. In parallel, physics
is calling for a shorter scale application of the LAr TPC technique at the
level of 100 ton mass, for low energy neutrino physics and for use as a near
station setup in future long baseline neutrino facilities. We outline here the
main physics objectives and the design of such a detector for operation in the
upcoming T2K neutrino beam. We finally present the result of a series of R&D
studies conducted with the aim of validating the design of the proposed
detectors.Comment: 16 pages, 18 figures, Invited talk at High Intensity Physics HIF05,
La Biodola, Isola d'Elba (Italy), June 200
An adjustable focusing system for a 2 MeV H- ion beam line based on permanent magnet quadrupoles
A compact adjustable focusing system for a 2 MeV H- RFQ Linac is designed,
constructed and tested based on four permanent magnet quadrupoles (PMQ). A PMQ
model is realised using finite element simulations, providing an integrated
field gradient of 2.35 T with a maximal field gradient of 57 T/m. A prototype
is constructed and the magnetic field is measured, demonstrating good agreement
with the simulation. Particle track simulations provide initial values for the
quadrupole positions. Accordingly, four PMQs are constructed and assembled on
the beam line, their positions are then tuned to obtain a minimal beam spot
size of (1.2 x 2.2) mm^2 on target. This paper describes an adjustable PMQ beam
line for an external ion beam. The novel compact design based on commercially
available NdFeB magnets allows high flexibility for ion beam applications.Comment: published in JINST (4th Feb 2013
Nuclear Emulsion Film Detectors for Proton Radiography: Design and Test of the First Prototype
Proton therapy is nowadays becoming a wide spread clinical practice in cancer
therapy and sophisticated treatment planning systems are routinely used to
exploit at best the ballistic properties of charged particles. The information
on the quality of the beams and the range of the protons is a key issue for the
optimization of the treatment. For this purpose, proton radiography can be used
in proton therapy to obtain direct information on the range of the protons, on
the average density of the tissues for treatment planning optimization and to
perform imaging with negligible dose to the patient. We propose an innovative
method based on nuclear emulsion film detectors for proton radiography, a
technique in which images are obtained by measuring the position and the
residual range of protons passing through the patient's body. Nuclear emulsion
films interleaved with tissue equivalent absorbers can be fruitfully used to
reconstruct proton tracks with very high precision. The first prototype of a
nuclear emulsion based detector has been conceived, constructed and tested with
a therapeutic proton beam at PSI. The scanning of the emulsions has been
performed at LHEP in Bern, where a fully automated microscopic scanning
technology has been developed for the OPERA experiment on neutrino
oscillations. After track reconstruction, the first promising experimental
results have been obtained by imaging a simple phantom made of PMMA with a step
of 1 cm. A second phantom with five 5 x 5 mm^2 section aluminum rods located at
different distances and embedded in a PMMA structure has been also imaged.
Further investigations are in progress to improve the resolution and to image
more sophisticated phantoms.Comment: Presented at the 11th ICATPP Conference on Astroparticle, Particle,
Space Physics, Detectors and Medical Physics Applications, Como (Italy),
October 200
30 kV coaxial vacuum-tight feedthrough for operation at cryogenic temperatures
In this paper we describe the technology of building a vacuum-tight high
voltage feedthrough which is able to operate at voltages up to 30 kV. The
feedthrough has a coaxial structure with a grounded sheath which makes it
capable to lead high voltage potentials into cryogenic liquids, without risk of
surface discharges in the gas phase above the liquid level. The feedthrough is
designed to be used in ionization detectors, based on liquefied noble gases,
such as Argon or Xenon
A steerable UV laser system for the calibration of liquid argon time projection chambers
A number of liquid argon time projection chambers (LAr TPC's) are being build
or are proposed for neutrino experiments on long- and short baseline beams. For
these detectors a distortion in the drift field due to geometrical or physics
reasons can affect the reconstruction of the events. Depending on the TPC
geometry and electric drift field intensity this distortion could be of the
same magnitude as the drift field itself. Recently, we presented a method to
calibrate the drift field and correct for these possible distortions. While
straight cosmic ray muon tracks could be used for calibration, multiple coulomb
scattering and momentum uncertainties allow only a limited resolution. A UV
laser instead can create straight ionization tracks in liquid argon, and allows
one to map the drift field along different paths in the TPC inner volume. Here
we present a UV laser feed-through design with a steerable UV mirror immersed
in liquid argon that can point the laser beam at many locations through the
TPC. The straight ionization paths are sensitive to drift field distortions, a
fit of these distortion to the linear optical path allows to extract the drift
field, by using these laser tracks along the whole TPC volume one can obtain a
3D drift field map. The UV laser feed-through assembly is a prototype of the
system that will be used for the MicroBooNE experiment at the Fermi National
Accelerator Laboratory (FNAL)
Ionization signals from electrons and alpha-particles in mixtures of liquid Argon and Nitrogen - perspectives on protons for Gamma Resonant Nuclear Absorption applications
In this paper we report on a detailed study of ionization signals produced by
Compton electrons and alpha-particles in a Time Projection Chamber (TPC) flled
with different mixtures of liquid Argon and Nitrogen. The measurements were
carried out with Nitrogen concentrations up to 15% and a drift electric feld in
the range 0-50 kV/cm. A prediction for proton ionization signals is made by
means of interpolation. This study has been conducted in view of the possible
use of liquid Ar-N2 TPCs for the detection of gamma-rays in the resonant band
of the Nitrogen absorption spectrum, a promising technology for security and
medical applications
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