Instruments

14 pages, 2512 KiB

Open AccessArticle

Characterization and Pilot Human Trial of Dedicated Breast Ring Positron Emission Tomography (BRPET) System

by Andrew M. Polemi, Annie K. Kogler, Patrice K. Rehm, Luke Lancaster, Heather R. Peppard, Patrick M. Dillon, Alexander V. Stolin, Stanislaw Majewski and Mark B. Williams

Instruments 2021, 5(3), 30; https://doi.org/10.3390/instruments5030030 - 10 Sep 2021

Cited by 2 | Viewed by 2483

Abstract

We describe the design and performance of BRPET, a novel dedicated breast PET (dbPET) scanner designed to maximize visualization of posterior regions of the breast. BRPET uses prone imaging geometry and a 12-module detector ring built from pixelated LYSO crystals coupled to position [...] Read more.

We describe the design and performance of BRPET, a novel dedicated breast PET (dbPET) scanner designed to maximize visualization of posterior regions of the breast. BRPET uses prone imaging geometry and a 12-module detector ring built from pixelated LYSO crystals coupled to position sensitive photomultiplier tubes (PSPMTs). Optical coupling via slanted plastic fiber optic light guides permits partial insertion of the crystals into the exam table’s breast aperture. Image quality testing procedures were adapted from the NEMA NU4-2008 protocol. Two additional phantom tests quantified the posterior extent of the usable volume of view (VoV). BRPET axial, radial, and tangential FWHM spatial resolutions at the isocenter were 1.8, 1.7, and 1.9 mm, respectively. The peak absolute system sensitivity was 0.97% using an energy window of 460–562 keV. The peak noise equivalent counting rate was 5.33 kcps at 21.6 MBq. The scanner VoV extends to within ~6 mm of the plane defining the location of the chest wall. A pilot human study (n = 10) compared the diagnostic performance of FDG-BRPET to that of contrast enhanced MRI (CEMRI), with biopsy as ground truth. Averaged over three expert human observers, the sensitivity/specificity for BRPET was 0.93/1.0, compared to 1.0/0.25 for CEMRI. Full article

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25 pages, 18439 KiB

Open AccessArticle

Impact of Different Components and Boundary Conditions on the Eigenfrequencies of a Magnet–Girder Assembly

by Simone Andresen

Instruments 2021, 5(3), 29; https://doi.org/10.3390/instruments5030029 - 1 Sep 2021

Cited by 2 | Viewed by 4124

Abstract

Synchrotron radiation facilities are very important in different areas of fundamental and applied science to investigate structures or processes at small scales. Magnet–girder assemblies play a key role for the performance of such accelerator machines. High structural eigenfrequencies of the magnet–girder assemblies are [...] Read more.

Synchrotron radiation facilities are very important in different areas of fundamental and applied science to investigate structures or processes at small scales. Magnet–girder assemblies play a key role for the performance of such accelerator machines. High structural eigenfrequencies of the magnet–girder assemblies are required to assure a sufficient particle beam stability. The objective of the present parametric study was to numerically investigate and quantify the impact of different boundary conditions and components on the magnet–girder eigenfrequencies. As case studies, two 3 m long girder designs following the specifications of the PETRA IV project at DESY (German Electron Synchrotron, Hamburg, Germany) were selected. High magnet–girder assembly eigenfrequencies were achieved by, e.g., positioning the magnets close to the upper girder surface, increasing the connection stiffness between the magnets and the girder and between the girder and the bases, and positioning the girder support points as high as possible in the shape of a large triangle. Comparing the

\sqrt{E / ρ}

ratio (E: Young’s modulus,

ρ

: material density) of different materials was used as a first approach to evaluate different materials for application to the girder. Based on the findings, general principles are recommended to be considered in the future girder design development processes. Full article

(This article belongs to the Special Issue Recent Advance in Particle Accelerator Instrumentation)

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17 pages, 2779 KiB

Open AccessArticle

Commissioning Results and Electron Beam Characterization with the S-Band Photoinjector at SINBAD-ARES

by Eva Panofski, Ralph Assmann, Florian Burkart, Ulrich Dorda, Luca Genovese, Farzad Jafarinia, Sonja Jaster-Merz, Max Kellermeier, Willi Kuropka, Francois Lemery, Barbara Marchetti, Daniel Marx, Frank Mayet, Thomas Vinatier and Sumera Yamin

Instruments 2021, 5(3), 28; https://doi.org/10.3390/instruments5030028 - 25 Aug 2021

Cited by 13 | Viewed by 3131

Abstract

Over the years, the generation and acceleration of ultra-short, high quality electron beams has attracted more and more interest in accelerator science. Electron bunches with these properties are necessary to operate and test novel diagnostics and advanced high-gradient accelerating schemes, such as plasma [...] Read more.

Over the years, the generation and acceleration of ultra-short, high quality electron beams has attracted more and more interest in accelerator science. Electron bunches with these properties are necessary to operate and test novel diagnostics and advanced high-gradient accelerating schemes, such as plasma accelerators and dielectric laser accelerators. Furthermore, several medical and industrial applications require high-brightness electron beams. The dedicated R&D facility ARES at DESY (Deutsches Elektronen-Synchrotron) will provide such probe beams in the upcoming years. After the setup of the normal-conducting, radio-frequency (RF) photoinjector and linear accelerating structures, ARES successfully started the beam commissioning of the RF gun. This paper gives an overview of the ARES photoinjector setup and summarizes the results of the gun commissioning process. The quality of the first electron beams is characterized in terms of charge, momentum, momentum spread and beam size. Additionally, the dependencies of the beam parameters on RF settings are described. All measurement results of the characterized beams fulfill the requirements for operating the ARES linac with this RF photoinjector. Full article

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18 pages, 2618 KiB

Open AccessArticle

Quench Detection and Protection for High-Temperature Superconductor Accelerator Magnets

by Maxim Marchevsky

Instruments 2021, 5(3), 27; https://doi.org/10.3390/instruments5030027 - 5 Aug 2021

Cited by 39 | Viewed by 8265

Abstract

High-temperature superconductors (HTS) are being increasingly used for magnet applications. One of the known challenges of practical conductors made with high-temperature superconductor materials is a slow normal zone propagation velocity resulting from a large superconducting temperature margin in combination with a higher heat [...] Read more.

High-temperature superconductors (HTS) are being increasingly used for magnet applications. One of the known challenges of practical conductors made with high-temperature superconductor materials is a slow normal zone propagation velocity resulting from a large superconducting temperature margin in combination with a higher heat capacity compared to conventional low-temperature superconductors (LTS). As a result, traditional voltage-based quench detection schemes may be ineffective for detecting normal zone formation in superconducting accelerator magnet windings. A developing hot spot may reach high temperatures and destroy the conductor before a practically measurable resistive voltage is detected. The present paper discusses various approaches to mitigating this problem, specifically focusing on recently developed non-voltage techniques for quench detection. Full article

(This article belongs to the Special Issue Applied Superconductivity for Particle Accelerator)

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30 pages, 17889 KiB

Open AccessArticle

Pulse-Height and 2-D Charge-Spread Single-Pixels Studies on a LuYAP:Ce Scintillation Array

by Raffaele Scafè, Marco Puccini, Rosanna Pellegrini and Roberto Pani

Instruments 2021, 5(3), 26; https://doi.org/10.3390/instruments5030026 - 30 Jul 2021

Viewed by 2712

Abstract

The present work deals with a 10 × 10 array of (Lu_0.7Y_0.3)AP:Ce 2 × 2 × 10 mm³ pixels, manufactured by Crytur (Cz), that has been utilized in a previous paper. The crystal-array has been coupled to an [...] Read more.

The present work deals with a 10 × 10 array of (Lu_0.7Y_0.3)AP:Ce 2 × 2 × 10 mm³ pixels, manufactured by Crytur (Cz), that has been utilized in a previous paper. The crystal-array has been coupled to an 8 × 8 anodes H10966 model Hamamatsu (Jp) Position-Sensitive Photo Multiplier Tube (PSPMT) connected to electronics for single events scintillation read-out. The response of such a detector has been studied under Co-57, or Ba-133, or Cs-137 gamma-ray emissions, as well as with Lu-176 self-activity only. The present work is aimed at characterizing the individual crystal-pixels’ single-event responses in terms of pulse-height and of spreads of the 2-D charge-distributions. In particular, the charge-spread characterization pointed out several defects in the crystal-array assembly, not detected by usual pulse-height studies. The diagnostic method based on charge-spread analysis seems also well suited for scintillation array characterizations for gamma-ray detectors studies, as well as for quality controls of such pixelated devices during the lifetime of systems in the field of radionuclide medical imaging (SPECT and PET). The method is also appropriate for other applications where gamma-ray spectroscopy is required, like nuclear physics, astrophysics, astroparticle physics, homeland security, and non-proliferation. Full article

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15 pages, 10381 KiB

Open AccessEditor’s ChoiceArticle

Josephson Junctions as Single Microwave Photon Counters: Simulation and Characterization

by Alessio Rettaroli, David Alesini, Danilo Babusci, Carlo Barone, Bruno Buonomo, Matteo Mario Beretta, Gabriella Castellano, Fabio Chiarello, Daniele Di Gioacchino, Giulietto Felici, Giovanni Filatrella, Luca Gennaro Foggetta, Alessandro Gallo, Claudio Gatti, Carlo Ligi, Giovanni Maccarrone, Francesco Mattioli, Sergio Pagano, Simone Tocci and Guido Torrioli

Instruments 2021, 5(3), 25; https://doi.org/10.3390/instruments5030025 - 16 Jul 2021

Cited by 11 | Viewed by 4345

Abstract

Detection of light dark matter, such as axion-like particles, puts stringent requirements on the efficiency and dark-count rates of microwave-photon detectors. The possibility of operating a current-biased Josephson junction as a single-microwave photon-detector was investigated through numerical simulations, and through an initial characterization [...] Read more.

Detection of light dark matter, such as axion-like particles, puts stringent requirements on the efficiency and dark-count rates of microwave-photon detectors. The possibility of operating a current-biased Josephson junction as a single-microwave photon-detector was investigated through numerical simulations, and through an initial characterization of two Al junctions fabricated by shadow mask evaporation, done in a dilution refrigerator by measuring escape currents at different temperatures, from 40 mK up to the Al transition temperature. The escape dynamics of the junctions were reproduced in the simulation, including the dissipative effects. Inhibition of thermal activation was observed, leaving the macroscopic quantum tunneling as the dominant effect well beyond the crossover temperature. Full article

(This article belongs to the Special Issue Innovative Experimental Techniques for Direct Dark Matter Detection)

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13 pages, 2049 KiB

Open AccessArticle

An Active Plasma Beam Dump for EuPRAXIA Beams

by Alexandre Bonatto, Roger Pizzato Nunes, Bruno Silveira Nunes, Sanjeev Kumar, Linbo Liang and Guoxing Xia

Instruments 2021, 5(3), 24; https://doi.org/10.3390/instruments5030024 - 5 Jul 2021

Cited by 1 | Viewed by 3334

Abstract

Plasma wakefields driven by high power lasers or relativistic particle beams can be orders of magnitude larger than the fields produced in conventional accelerating structures. Since the plasma wakefield is composed not only of accelerating but also of decelerating phases, this paper proposes [...] Read more.

Plasma wakefields driven by high power lasers or relativistic particle beams can be orders of magnitude larger than the fields produced in conventional accelerating structures. Since the plasma wakefield is composed not only of accelerating but also of decelerating phases, this paper proposes to utilize the strong decelerating field induced by a laser pulse in the plasma to absorb the beam energy, in a scheme known as the active plasma beam dump. The design of this active plasma beam dump has considered the beam output by the EuPRAXIA facility. Analytical estimates were obtained, and compared with particle-in-cell simulations. The obtained results indicate that this active plasma beam dump can contribute for more compact, safer, and greener accelerators in the near future. Full article

(This article belongs to the Special Issue Feature Papers in Instruments 2021–2022)

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Instruments, Volume 5, Issue 3 (September 2021) – 7 articles

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