Calibration of the VIRGO central interferometer Véziant, Olivier; Collaboration, the VIRGO
Classical and Quantum Gravity,
09/2003, Volume:
20, Issue:
17
Journal Article, Conference Proceeding
The sensitivity of a gravitational wave detector based on a laser interferometer is limited by photon shot noise for signals with frequencies above a few hundred hertz. The amplitude of this noise ...depends on the interferometer fringe contrast. By means of a complete simulation, we show that using a short optical cavity placed at the interferometer output port, the contrast can be significantly improved and the optimal sensitivity recovered. Such an output mode-cleaner has been realized and tested. The adopted design and the results of the tests are presented.
Characterization study of silica aerogel for Cherenkov imaging Sallaz-Damaz, Y.; Derome, L.; Mangin-Brinet, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2010, Volume:
614, Issue:
2
Journal Article
Peer reviewed
Open access
Different methods to measure the characteristics of silica aerogel tiles used as Cherenkov radiator in the CREAM and AMS experiments have been investigated to optimize the detector performances. The ...measurement accuracy dictated by the physics objectives on the velocity and charge resolutions set stringent requirements on the aerogel refractive index determination, namely
Δ
n
∼
1.5
×
10
−
4
and
Δ
n
∼
5
×
10
−
4
for the AMS and CREAM imagers, respectively. The matching of such accuracies for this material turned out to be a metrological challenge, and finally led to a full R&D program, to develop an appropriate characterization procedure. Preliminary studies performed with a standard refractive index measurement technique (laser beam deviation by a prism) have revealed a significant systematic index nonuniformity for the AMS tiles at a level
(
10
−
3
)
, not acceptable considering the aimed accuracy. These large variations were confirmed in a beam test. A second method, mapping the transverse index gradient by deflection of a laser beam entering normally to the tile has then been developed. It is shown that this procedure is suitable to reach the required accuracy, at the price of using both methods combined. The several hundreds of tiles of the radiator plane of the CREAM and AMS Cherenkov imagers were characterized using a simplified procedure, however, appropriate for each case, compromising between the amount of work and the time available. The experimental procedures and set-ups used are described in the text, and the obtained results are reported.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
4.
Prototype study of the Cherenkov imager of the AMS experiment Aguayo, P.; Aguilar-Benitez, M.; Arruda, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2006, Volume:
560, Issue:
2
Journal Article
Peer reviewed
Open access
The AMS experiment includes a Cherenkov imager for mass and charge identification of charged cosmic rays. A second generation prototype has been constructed and its performances evaluated both with ...cosmic ray particles and with beam ions. In-beam tests have been performed using secondary nuclei from the fragmentation of
20
GeV
/
c
per nucleon Pb ions and
158
GeV
/
c
per nucleon In from the CERN SPS in 2002 and 2003. Partial results are reported. The performances of the prototype for the velocity and the charge measurements have been studied over the range of ion charge
Z
≲
30
. A sample of candidate silica aerogel radiators for the flight model of the detector has been tested. The measured velocity resolution of the detector was found to scale with
Z
-
1
as expected, with a value
σ
(
β
)
/
β
≈
0.7
–
110
-
3
for singly charged particles and an asymptotic limit in
Z of 0.4–
0.6
×
10
-
4
. The measured charge resolution obtained for the
n
=
1.05
aerogel radiator material selected for the flight model of the detector is
σ
(
Z
)
=
0.18
(statistical)
⊕
0.015 (systematic), ensuring a good charge separation up to the iron element, for the prototype in the reported experimental conditions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper presents a complete description of Virgo, the French-Italian gravitational wave detector. The detector, built at Cascina, near Pisa (Italy), is a very large Michelson interferometer, with ...3 km-long arms. In this paper, following a presentation of the physics requirements, leading to the specifications for the construction of the detector, a detailed description of all its different elements is given. These include civil engineering infrastructures, a huge ultra-high vacuum (UHV) chamber (about 6000 cubic metres), all of the optical components, including high quality mirrors and their seismic isolating suspensions, all of the electronics required to control the interferometer and for signal detection. The expected performances of these different elements are given, leading to an overall sensitivity curve as a function of the incoming gravitational wave frequency. This description represents the detector as built and used in the first data-taking runs. Improvements in different parts have been and continue to be performed, leading to better sensitivities. These will be detailed in a forthcoming paper.
A test bench for the AMS-RICH photodetector modules Vargas-Trevino, M.; Ballon, J.; Barrau, A. ...
Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.04CH37510),
2004, Volume:
3
Conference Proceeding
The Alpha Magnetic Spectrometer experiment to be installed on the International Space Station will be equipped with a Proximity Focusing Ring Imaging Cerenkov detector for ion identification. A ...prototype (2nd generation) has been constructed, which performances have been evaluated both with Cosmic Ray particles and beam ions. A test bench (PMT and Front End Electronics selection) was developed for the testing of the photodetector modules of the flight model. It is described in this contribution.
The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be installed on the International Space Station (ISS) for at least 3 years, is a detector designed to measure charged cosmic ...ray spectra with energies up to the TeV region and with high energy photon detection capability up to a few hundred GeV. It is equipped with several subsystems, one of which is a proximity focusing RICH detector with a dual radiator (aerogel+NaF) that provides reliable measurements for particle velocity and charge. The assembly and testing of the AMS RICH is currently being finished and the full AMS detector is expected to be ready by the end of 2008. The RICH detector of AMS-02 is presented. Physics prospects are briefly discussed.
The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). ...This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored. The algorithms developed to fulfill these requirements are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed.
The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the
International Space Station (ISS) will be equipped with a proximity focusing
Ring Imaging Cherenkov (RICH) detector for ...measuring the electric charge and
velocity of the charged cosmic particles. A RICH prototype consisting of 96
photomultiplier units, including a piece of the conical reflector, was built
and its performance evaluated with ion beam data. Preliminary results of the
in-beam tests performed with ion fragments resulting from collisions of a 158
GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported.
The collected data included tests to the final front-end electronics and to
different aerogel radiators. Cherenkov rings for a large range of charged
nuclei and with reflected photons were observed. The data analysis confirms the
design goals. Charge separation up to Fe and velocity resolution of the order
of 0.1% for singly charged particles are obtained.
