12 research outputs found
muCool: A novel low-energy muon beam for future precision experiments
Experiments with muons () and muonium atoms () offer
several promising possibilities for testing fundamental symmetries. Examples of
such experiments include search for muon electric dipole moment, measurement of
muon and experiments with muonium from laser spectroscopy to gravity
experiments. These experiments require high quality muon beams with small
transverse size and high intensity at low energy.
At the Paul Scherrer Institute, Switzerland, we are developing a novel device
that reduces the phase space of a standard beam by a factor of
with efficiency. The phase space compression is achieved by
stopping a standard beam in a cryogenic helium gas. The stopped
are manipulated into a small spot with complex electric and magnetic
fields in combination with gas density gradients. From here, the muons are
extracted into the vacuum and into a field-free region. Various aspects of this
compression scheme have been demonstrated. In this article the current status
will be reported.Comment: 8 pages, 5 figures, TCP 2018 conference proceeding
Development of wide range photon detection system for muonic X-ray spectroscopy
We have developed a photon detection system for muonic X-ray spectroscopy.
The detector system consists of high-purity germanium detectors with BGO
Compton suppressors. The signals from the detectors are readout with a digital
acquisition system. The absolute energy accuracy, energy and timing
resolutions, photo-peak efficiency, the performance of the Compton suppressor,
and high count rate durability are studied with standard -ray sources
and in-beam experiment using
resonance reaction. The detection system was demonstrated at Paul Scherrer
Institute. A calibration method for a photon detector at a muon facility using
muonic X-rays of Au and Bi is proposed
Silicon microchannel frames for high-energy physics experiments
The design of detectors used for experiments in high-energy physics requires a light,
stiff, and efficient cooling system with a low material budget. The use of silicon microchannel
cooling plates has gained considerable interest in the last decade. In this study, we propose the
development of silicon microchannel cooling frames studied within the framework of the major
upgrade of the Inner Tracking System (ITS) of the ALICE experiment at CERN. The preliminary
results obtained with these frames demonstrate that they can withstand the internal pressure arising
from the flow of the coolant with a limited mass penalt
Room-temperature emission of muonium from aerogel and zeolite targets
Novel emitters of muonium (Mu = mu+ + e-) with high conversion efficiencies can enhance the precision of muonium spectroscopy experiments and enable next-generation searches for new physics. At the Paul Scherrer Institute (PSI), we investigate muonium production at room-temperature as well as in cryogenic environment using a superfluid helium converter. In this paper, we describe the development of compact detection schemes which resulted in the background-suppressed observation of atomic muonium in vacuum, and can be adapted for cryogenic measurements. Using these setups, we compared the emission characteristics of various muonium production targets at room temperature using low momentum (p mu = 11-13 MeV/c) muons, and observed muonium emission from zeolite targets into vacuum. For a specific laser-ablated aerogel target, we determined a muon-to-vacuum-muonium conversion efficiency of 7.23 +/- 0.05(stat)+1.06 -0.76(sys) %, assuming thermal emission of muonium. Moreover, we investigated muonium-helium collisions and from it we determined an upper temperature limit of 0.3 K for the superfluid helium converter
Measurement of the quadrupole moment of Re-185 and Re-187 from the hyperfine structure of muonic X rays
The hyperfine splitting of the 5g -> 4f transitions in muonic 185,187-Re has been measured using high resolution HPGe detectors and compared to state-of-the-art atomic theoretical predictions. The spectroscopic quadrupole moment has been extracted using modern fitting procedures and compared to the values available in literature obtained from muonic X rays of natural rhenium. The extracted values of the nuclear spectroscopic quadrupole moment are 2.07(5) barn and 1.94(5) barn, respectively for 185-Re and 187-Re. This work is part of a larger effort at the Paul Scherrer Institut towards the measurement of the nuclear charge radii of radioactive elements.Available on ArXiv: https://arxiv.org/abs/2003.02481status: publishe
Nuclear structure with radioactive muonic atoms
Muonic atoms have been used to extract the most accurate nuclear charge radii based on the detection of X-rays from the muonic cascades. Most stable and a few un- stable isotopes have been investigated with muonic atom spectroscopy techniques. A new research project recently started at the Paul Scherrer Institut aims to extend the high- resolution muonic atom spectroscopy for the precise determination of nuclear charge radii and other nuclear structure properties of radioactive isotopes. The challenge to combine the high-energy muon beam with small quantity of stopping mass is being addressed by developing the concept of stopping the muon in a high-density, a high-pressure hydrogen cell and subsequent transfer of the muon to the element of interest. Status and perspectives of the project will be presented.status: Published onlin
Muonic atom spectroscopy with microgram target material
Muonic atom spectroscopy -- the measurement of the x rays emitted during the formation process of a muonic atom -- has a long standing history in probing the shape and size of nuclei. In fact, almost all stable elements have been subject to muonic atom spectroscopy measurements and the absolute charge radii extracted from these measurements typically offer the highest accuracy available. However, so far only targets of at least a few hundred milligram could be used as it required to stop a muon beam directly in the target to form the muonic atom. We have developed a new method relying on repeated transfer reactions taking place inside a 100-bar hydrogen gas cell with an admixture of 0.25% deuterium that allows us to drastically reduce the amount of target material needed while still offering an adequate efficiency. Detailed simulations of the transfer reactions match the measured data, demonstrating good understanding of the processes taking place inside the gas mixture. As a proof of principle we demonstrate the method with a measurement of the 2p-1s muonic x rays from a 5-{\mu}g gold target
Muonic atom spectroscopy with microgram target material
Muonic atom spectroscopy -- the measurement of the x rays emitted during the formation process of a muonic atom -- has a long standing history in probing the shape and size of nuclei. In fact, almost all stable elements have been subject to muonic atom spectroscopy measurements and the absolute charge radii extracted from these measurements typically offer the highest accuracy available. However, so far only targets of at least a few hundred milligram could be used as it required to stop a muon beam directly in the target to form the muonic atom. We have developed a new method relying on repeated transfer reactions taking place inside a 100-bar hydrogen gas cell with an admixture of 0.25% deuterium that allows us to drastically reduce the amount of target material needed while still offering an adequate efficiency. Detailed simulations of the transfer reactions match the measured data, demonstrating good understanding of the processes taking place inside the gas mixture. As a proof of principle we demonstrate the method with a measurement of the 2p-1s muonic x rays from a 5-{\mu}g gold target
Nuclear structure with radioactive muonic atoms
Muonic atoms have been used to extract the most accurate nuclear charge radii based on the detection of X-rays from the muonic cascades. Most stable and a few unstable isotopes have been investigated with muonic atom spectroscopy techniques. A new research project recently started at the Paul Scherrer Institut aims to extend the highresolution muonic atom spectroscopy for the precise determination of nuclear charge radii and other nuclear structure properties of radioactive isotopes. The challenge to combine the high-energy muon beam with small quantity of stopping mass is being addressed by developing the concept of stopping the muon in a high-density, a high-pressure hydrogen cell and subsequent transfer of the muon to the element of interest. Status and perspectives of the project will be presented
Towards nuclear structure with radioactive muonic atoms
International audienceThe muX project at the Paul Scherrer Institut aims to perform highresolution muonic atom X-ray spectroscopy for the extraction of nuclear charge radii of radioactive isotopes that can be handled only in microgram quantities. Measurements of the absolute charge radii of high-Z radioactive elements are complementary to the measurements of relative differences in mean-square radii along the isotopic chain available from laser spectroscopy. One of the major limitations of atomic structure calculations is related with the uncertainty of the nuclear charge radius. This is the case for the extraction of the Weinberg angle from atomic parity violation in 226Ra. A new approach to solve previous limitations of muonic atom X-ray spectroscopy experiments is the application of multiple muon transfer reactions in a high-pressure hydrogen gas cell with a small admixture of deuterium. The validity of this method has been demonstrated with a measurement with only 5 μg of gold