Detector Concept Research Articles

Acoustic neutrino detection in a Adriatic multidisciplinary observatory (ANDIAMO)

The existence of cosmic accelerators able to emit charged particles up to ZeV energies has been confirmed by the observations made in the last years by experiments such as Auger and Telescope Array. The interaction of such energetic cosmic-rays with gas or low energy photons, surrounding the astrophysical sources or present in the intergalactic medium, guarantee an ultra-high-energy neutrino related emission. When these energetic neutrinos interact in a medium produce a thermo-acoustic process where the energy of generated particle cascades can be conveyed in a pressure pulse propagating into the same medium. The kilometric attenuation length as well as the well-defined shape of the expected pulse suggest a large-area-undersea-array of acoustic sensors as an ideal observatory. For this scope, we propose to exploit the existing and no more operative offshore (oil rigs) powered platforms in the Adriatic sea as the main infrastructure to build an acoustic submarine array of dedicated hydrophones covering a surface area up to 10000 km2 and a volume up to 500 km3. In this work we describe the advantages of this detector concept using a ray tracing technique as well as the scientific goals linked to the challenging purpose of observing for the first time ultra-high-energy cosmic neutrinos. This observatory will be complementary to the dedicated radio array detectors with the advantages of avoiding any possible thermo-acoustic noise from the atmospheric muons.

Requirements and R&D for detectors at the future Electron–Ion Collider

The Electron–Ion Collider’s (EIC’s) ability to collide high-energy electron beams with high-energy ion beams will provide access to those regions in the nucleon and nuclei where their structure is dominated by gluons. Moreover, polarized beams in the EIC will give unique access to the spatial and spin structure of gluons and sea-quarks in the proton and light nuclei.The EIC will be an unprecedented collider with luminosities 2–3 orders of magnitude higher than previous e + p colliders over a very wide range of center-of-mass energies, from 20 to 140 GeV, while accommodating highly polarized electron and nucleon beams. Equally demanding are the requirements for the detector(s) that will be needed to carry out the physics program: hermetic coverage in tracking, calorimetry and particle ID within a wide pseudorapidity range, substantial angular and momentum acceptance in the hadron-going direction, as well as high quality hadronic calorimetry among others.This paper gives a brief overview of the detector requirements, current general-purpose detector concepts, and the ongoing EIC detector R&D efforts.

Picosecond timing of charged particles using the TORCH detector

TORCH is a large-area, high-precision time-of-flight (ToF) detector designed to provide charged-particle identification in the 2–20 GeV/c momentum range. Prompt Cherenkov photons emitted by charged hadrons as they traverse a 10 mm quartz radiator are propagated to the periphery of the detector, where they are focused onto an array of micro-channel plate photomultiplier tubes (MCP-PMTs). The position and arrival times of the photons are used to infer the particles’ time of entry in the radiator, to identify hadrons based on their ToF. The MCP-PMTs were developed with an industrial partner to satisfy the stringent requirements of the TORCH detector. The requirements include a finely segmented anode, excellent time resolution, and a long lifetime. Over an approximately 10 m flight distance, the difference in ToF between a kaon and a pion with 10 GeV/c momentum is 35 ps, leading to a 10–15 ps per track timing resolution requirement. On average 30 photons per hadron are detected, which translates to a single-photon time resolution of 70 ps. The TORCH R&D program aims to demonstrate the validity of the detector concept through laboratory and beam tests, results from which are presented. A timing resolution of 70–100 ps was reached in beam tests, approaching the TORCH design goal. Laboratory timing tests consist of operating the MCP-PMTs coupled to the TORCH readout electronics. A time resolution of 50 ps was measured, meeting the TORCH target timing resolution.

Design rules for time of flight Positron Emission Tomography (ToF-PET) heterostructure radiation detectors

Despite the clinical acceptance of ToF-PET, there is still a gap between the technology's performance and the end-user's needs. Core to bridging this gap is the ability to develop radiation detectors combining a short attenuation length and a sub-nanosecond time response. Currently, the detector of choice, Lu2SiO5:Ce3+ single crystal, is not selected for its ability to answer the performance needs, but as a trade-off between requirements and availability. To bypass the current performance limitations, in particular restricted time response, the concept of the heterostructured detector has been proposed. The concept aims at splitting the scintillation mechanisms across two materials, one acting primarily as an absorber and one as an ultra-fast emitter. If the concept has attracted the interest of the medical and material communities, little has been shown in terms of the benefits/limitations of the approach. Based on Monte Carlo simulations, we present a survey of heterostructure performance versus detector design. The data allow for a clear understanding of the design/performance relationship. This, in turn, enables the establishment of design rules toward the development and optimization of heterostructured detectors that could supersede the current detector technology in the medical imaging field but also across multiple sectors (e.g. high-energy physics, security).

The Mu3e detector

The Mu3e experiment searches for the lepton flavour violating decay μ → eee with an ultimate sensitivity of 1 event in 1016 decays. This goal can only be achieved by reducing the material budget per tracking layer to X/X 0 ≈ 0.1%. For this purpose, the tracking detector is based on High Voltage Monolithic Active Pixel Sensors (HV-MAPS) thinned to 50 µm. The powering and data transmission is performed by means of polyimide-aluminum HDIs, which serve as mechanical support as well. The detector concept is presented, focusing on the technical aspects of the pixel tracker and the associated challenges.

Always-On Sparse Event Wake-Up Detectors: A Review

Recently there has been a significant increase in demand for wireless sensor networks, as their field of application is rapidly expanding, driven mostly by the growing importance and prevalence of the Internet of Things concept. To enable practical application of wireless sensor networks, sensor nodes must be inexpensive, small, light-weight, intelligent and autonomous. This paper presents a review of low-power always-on wake-up detectors used to reduce a sensor node’s power consumption and enable continuous detection of sparse events. We describe the wake-up concept, discuss its advantages and present the wake-up detector’s power consumption, detection accuracy and false positive rate as parameters of interest. We present a state-of-the-art analysis of wake-up detectors, grouping them based on their power consumption into zero-power and near-zero-power detectors and active detectors, which we further separate based on their implementation into digital detectors and mixed-signal and analog detectors. This analysis shows state-of-the-art wake-up detectors operate with detection accuracy over 90% and a wide range of power consumptions, spanning from a few nW to few tens of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> , because of their diverse applications and sensor modalities. Additionally, it shows that active mixed-signal wake-up detectors are currently the most utilized implementation, with emphasis on acoustic transducer modality. It also shows potential trends for future detector design utilizing more MEMS and NEMS to further lower detector power consumption. We also show techniques and ideas not yet integrated in the wake-up concept, to potentially improve the wake-up detector concept and present the wake-up detectors’ common applications and their specifics.

NuSD: A Geant4 based simulation framework for segmented anti-neutrino detectors

NuSD: Neutrino Segmented Detector is a Geant4-based user application that simulates inverse beta decay events in a variety of segmented scintillation detectors developed by different international collaborations. This simulation framework uses a combination of cross-programs and libraries including Geant4, ROOT and CLHEP developed and used by the high energy physics community. It will enable the neutrino physics community to simulate and study neutrino interactions within different detector concepts using a single program. In addition to neutrino simulations in segmented detectors, this program can also be used for various research projects utilizing scintillation detectors for different physics applications. Program summaryProgram title: NuSDCPC Library link to program files:https://doi.org/10.17632/7vgfhxbzdv.1Licensing provisions: GNU General Public License 3Programming language: C++External routines/libraries: Geant4, CLHEP, ROOT, CMAKENature of problem: Considerable effort has been spent on small anti-neutrino detectors for various purposes by different collaborations around the globe, but there is not an interactive and user-friendly joint-simulation framework.Solution method: To fulfill the need in the field, we developed a simulation framework to combine various segmented detector technologies. This package code will be open to public to let people simulate and test different detector concepts easily. Here, we categorized segmented anti-neutrino detectors as homogeneous and inhomogeneous detectors. Homogeneous detectors consist of PROSPECT, NULAT, and HSP type detectors. Inhomogeneous detectors consist of PANDA type detectors with single scintillator modules. CHANDLER, SOLID and SWEANY detector types are characterized as composite scintillator modules.

Calculation of Spatial Response of a Collimated Segmented HPGe Detector for Gamma Emission Tomography by MCNP Simulations

We have proposed a planar electronically segmented high-purity germanium (HPGe) detector concept in combination with a multislit collimator for gamma emission tomography. In this work, the spatial resolution achievable using the collimated segmented HPGe detector was evaluated, prior to the manufacture and operation of the detector. The spatial response of a collimated segmented HPGe detector concept was evaluated using simulations performed with Monte Carlo N-Particle (MCNP) transport code MCNP6. The full detector and multislit collimator system were modeled, and for the quantification of the spatial response, the modulation transfer function (MTF) was chosen as a performance metric. The MTF curve was obtained through the calculation of the line spread function (LSF) by analyzing the simulated projection data. In addition, tomographic reconstructions of the simulated simplified test objects were made to demonstrate the performance of the segmented HPGe detector in planned application. For 662-keV photons, the spatial resolution obtained was approximately the same as the collimator slit width for both the 100- and 150-mm-long collimators. The corresponding spatial resolution at 1596-keV photon energy was almost twice the slit width for the 100-mm collimator, due to the partial penetration of the high-energy gamma rays through the collimator bulk. For a 150-mm-long collimator, an improved resolution was obtained.

Prospects of charge signal analyses in liquid xenon TPCs with proportional scintillation in the liquid phase

As liquid xenon TPCs increase in target mass while pursuing the direct detection of WIMP dark matter, the technical challenges arising due to their size call for new solutions and open the discussion on alternative detector concepts. Proportional scintillation in liquid xenon allows for a single-phase design evading problems related to the liquid-gas interface and the precise gas gap required in a dual-phase TPC.Aside from a different scintillation mechanism, the successful detection- and analysis scheme of state-of-the-art experiments is maintained in this approach.We study the impact on charge signal analysis in a single-phase detector of DARWIN dimensions, where the fast timing of the proportional scintillation signal allows for the precise identification of the single electrons in the ionisation signal.Such a discrete electron-counting approach can lead to a better signal resolution for low energies when compared to the classical dual-phase continuous method.The absence of the liquid-gas interface can further benefit the S2-only energy resolution significantly. This can reduce the uncertainties from the scintillation and signal-detection process to a level significantly below the irreducible fluctuation in the primary ionisation. Exploiting the precise electron arrival time information can further allow for a powerful single vs. multiple site interaction discrimination with 93% rejection efficiency and 98% signal acceptance. This outperforms the design goal of the DARWIN observatory by a reduction factor of 4.2 in non-rejected multiple site neutron events.

Monte Carlo simulations of energy, time and spatial evolution of primary electrons generated by 511 keV photons in various scintillators

The intermediate phases between the initial interaction of ionizing radiation in scintillators and the production of scintillation light have been extensively studied over the years. Observable features of scintillators such as energy and time resolution have been in part explained through pre-scintillation mechanisms. Whereas the early energy transfer processes following the photoelectric (or Compton) interaction of an energetic photon with an atomic electron in scintillator materials were fully described, their spatio-temporal characteristics have had limited quantification. For 511 keV photon interaction in (TOF-)PET detectors, the production of a primary electron carrying most of the energy leads to non-localized energy deposit distribution having some temporal extent. Here, we characterize the spatial, temporal and energy evolution of the primary electron generated by 511 keV photons in different scintillators using Monte Carlo simulations. We aim to provide a general quantitative description detailing the dynamics of energy transfer, such as the electron ejection angle, track length and tortuosity, time course and remaining energy as a function of the initial interaction point. Simulation results show that the electron track is tortuous with a short extent and a rapid energy transfer within 100 μm in high-Z (e.g., BGO) or high density (e.g., LuAP:Ce) materials while the extent nearly doubles in lighter materials like BaF2 in which the track tortuosity is 10%–50% lower. The time fluctuations of the photoelectron full energy deposit remain below 1 ps FWHM, therefore adding negligible jitter to the time resolution of coincident detectors. These simulations provide a better understanding of the main carrier dynamics from simple characteristics as some detector concepts require low-range, contained energy deposit (e.g., pixelated crystal arrays) whereas others benefit from a greater extent of energy deposition (e.g., structures designed for energy sharing).

Concept of a fast neutron detector based on 10B-RPCs

We propose an alternative approach for the detection of fast neutrons in the energy range from 10-4 to 5 MeV based on 10B-RPCs (hybrid double-gap Resistive Plate Chambers with 10B4C neutron converters) surrounded by a polyethylene moderator. The detection efficiency as a function of the neutron energy is obtained in Monte Carlo simulations performed with the Geant4 toolkit for several detector configurations. The thickness of the neutron converter is optimized for the maximum efficiency. The results show that for this type of detector it is possible to obtain an average detection efficiency larger than 50% with a weak dependence on the neutron energy. The dark count rate and gamma sensitivity are also discussed.

Pathfinder for a high statistics search for missing energy in gamma cascades

We investigate the feasibility of a high statistics experiment to search for invisible decay modes in nuclear gamma cascades using 200 kg of %36 Cs(Tl) scintillators that are presently available at Texas A\&M. The experiment aims to search for missing energy by robustly establishing the absence of a photon in a well identified gamma cascade. We report on the experimental demonstration of the energy resolution necessary for this search. Prior explorations of this detector concept focused on baryonically coupled physics that could be emitted in $E_2$ transitions. We point out that this protocol can also search for particles that are coupled to photons by searching for the conversion of a photon produced in a gamma cascade into a hidden particle. Examples of these processes include the oscillation of a photon into a hidden photon and the conversion of a photon into an axion-like-particle either in the presence of a magnetic field or via the Primakoff process. This proof-of-concept apparatus appears to have the ability to search for hitherto unconstrained baryonically coupled scalars and pseudoscalars produced in $E_0$ and $M_0$ transitions. If successfully implemented, this experiment serves as a pathfinder for a larger detector with greater containment that can thoroughly probe the existence of new particles with mass below 4 MeV that lie in the poorly constrained supernova ``trapping window'' that exists between 100 keV and 30 MeV.

Advances in laboratory-scale ptychography using high harmonic sources [Invited

Extreme ultraviolet microscopy and wavefront sensing are key elements for next-generation ultrafast applications, such as chemically-resolved imaging, focal spot diagnostics in pump-and-probe experiments, and actinic metrology for the state-of-the-art lithography node at 13.5 nm wavelength. Ptychography offers a robust solution to the aforementioned challenges. Originally adapted by the electron and synchrotron communities, advances in the stability and brightness of high-harmonic tabletop sources have enabled the transfer of ptychography to the laboratory. This review covers the state of the art in tabletop ptychography with high harmonic generation sources. We consider hardware options such as illumination optics and detector concepts as well as algorithmic aspects in the analysis of multispectral ptychography data. Finally, we review technological application cases such as multispectral wavefront sensing, attosecond pulse characterization, and depth-resolved imaging.

First bent wafer-scale sensor in truly-cylindrical geometry for the ALICE ITS3 detector

An upgrade of the three innermost layers of the ALICE ITS, intended to be installed during the LHC Long Shutdown 3, is under development. The detector concept foresees the usage of curved, wafer-scale Monolithic Active Pixel Sensors. Extensive characterization studies of bent single ALPIDE chips (used for the current ITS), have been carried out to evaluate their performance under the mechanical stress involved in the bending process. These tests on small sensors have opened the way to the investigation of a large scale sensor: a full size demonstrator of a half-layer in a truly cylindrical shape based on so called super-ALPIDE chips. Such activity has required the development of special tools and procedures dedicated to bend and read out the new pixel matrix.

On the way to the 10 ps time-of-flight PET challenge

There is a consensus for gathering the multidisciplinary academic and industrial medical imaging community around the ambitious challenge to develop a 10 ps Time-of-Flight PET scanner (TOFPET). The goal is to reduce the radiation dose (currently 5–25 mSv for whole-body PET/CT) and/or scan time (currently > 10 min) by an order of magnitude, with a significant gain in the patient comfort and cost per exam (currently in the range of 1000 € per scan). To achieve this very ambitious goal it is essential to significantly improve the performance of each component of the detection chain: light production, light transport, photodetection, readout electronics. Speeding up progress in this direction is the goal of the challenge and will have an important impact on the development of a new generation of ionization radiation detectors. The possibility to reach 10 ps time-of-flight resolution at small energies (511 keV), as required in finely granulated calorimeters and PET scanners, although extremely challenging, is not limited by physical barriers and a number of disruptive technologies, such as multifunctional heterostructures, combining the high stopping power of well-known scintillators with the ultrafast photon emission resulting from the 1D, 2D or 3D quantum confinement of the excitons in nanocrystals, photonic crystals, photonic fibers, as well as new concepts of 3D digital SiPM structures, open the way to new radiation detector concepts with unprecedented performance.

MADMAX: a QCD dark matter axion direct-detection experiment

Peccei and Quinn proposed axions to solve the strong CP problem. Axions later turned out to be an excellent candidate for cold dark matter. They may have a mass of around 100 μeV if generated after cosmic inflation. The MADMAX collaboration aims to detect post-inflationary QCD axion using a new detector concept, the dielectric haloscope. It detects axion-induced traveling waves from boundaries of different media, boosted by layers of dielectrics. We report the current progress and future measurement plan for a proof-of-principle setup. We also report the current development of the prototype detector and the full MADMAX experiment.

The dark-PMT: a novel directional light Dark Matter detector based on vertically-aligned carbon nanotubes

We present the ‘dark-PMT’, a novel detector concept based around a target made of vertically-aligned carbon nanotubes. The detector is sensitive to electron recoils induced by sub-GeV dark matter, and is expected to have directional sensitivity and to be unaffected by thermal noise, even at room temperature. The key feature is that nanotubes are made of graphene, which is a two-dimensional material: therefore, if a dark matter particle transfers enough energy to an electron in the carbon lattice to overcome the work function (4.7 eV), the electron will be ejected directly into the vacuum. Because of the strong density anisotropy of nanotubes, the electrons will be capable of leaving the target, without being reabsorbed, if travelling in the direction of the tube axes. The electrons will then be accelerated, and reach an energy of 5 keV before hitting an electron sensor. We report on the most recent advancements towards the construction of a dark-PMT: a novel, state-of-the-art facility for nanotube synthesis has been recently installed in Rome, and it is being used to produce high-quality nanotubes; and detailed characterizations of silicon sensors with keV electrons have been performed.

Neutrino physics with an opaque detector

In 1956 Reines & Cowan discovered the neutrino using a liquid scintillator detector. The neutrinos interacted with the scintillator, producing light that propagated across transparent volumes to surrounding photo-sensors. This approach has remained one of the most widespread and successful neutrino detection technologies used since. This article introduces a concept that breaks with the conventional paradigm of transparency by confining and collecting light near its creation point with an opaque scintillator and a dense array of optical fibres. This technique, called LiquidO, can provide high-resolution imaging to enable efficient identification of individual particles event-by-event. A natural affinity for adding dopants at high concentrations is provided by the use of an opaque medium. With these and other capabilities, the potential of our detector concept to unlock opportunities in neutrino physics is presented here, alongside the results of the first experimental validation.

Muon detection at FCC-ee

Muons provide a clean experimental signature, typically traversing the whole experimental apparatus without decaying. Muon detection systems are therefore usually located at a rather large distance from the primary interaction vertex after all other sub-detectors. As such, experimental apparatuses at FCC-ee will certainly employ very large muon systems, covering areas of a few thousand square meters. For obvious reasons of cost, the most suitable detectors to realise these large muon systems are gas detectors. In particular, in recent years, micro-pattern gas detectors (MPGDs) have undergone very interesting developments, providing several new types of detectors with very good spatial and time resolution, high efficiency, high rate capability and high radiation tolerance. The good position and time resolution makes a MPGD an excellent particle tracker, reconstructing tracks at 4–5 m from the primary interaction vertex with sub-mm precision. Therefore MPGDs, apart from efficiently detecting muons, can precisely track and help identifying also hypothesized long lived particles (LLP) that would decay outside of the central trackers. MPGDs have the distinct advantage of being, at least for some detectors and some parts of them, mass-producible by industry, since they employ materials and manufacturing procedures that are used extensively for printed circuit boards (PCB) production. A particularly innovative MPGD, the mu RWELL, is considered as a possible candidate to build the large muon system of the IDEA detector concept for FCC-ee and is described in some more detail. Other technologies that could be considered for the realisation of muon detection systems are also briefly discussed.

Constraints on gluon distribution functions in the nucleon and nucleus from open charm hadron production at the Electron-Ion Collider

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will be a precision Quantum Chromodynamics machine that will enable a vast physics program with electron+proton/ion collisions across a broad center-of-mass range. Measurements of hard probes such as heavy flavor in deep inelastic scatterings will be an essential component to the EIC physics program and are one of the detector R\&D driving aspects. In this paper we study the projected statistical precision of open charm hadron production through exclusive hadronic channel reconstruction with a silicon detector concept currently being developed using a PYTHIA-based simulation. We further study the impact of possible intrinsic charm in the proton on projected data, and estimate the constraint on the nuclear gluon parton distribution function (PDF) from the charm structure functions $F_{2}^{c\overline{c}}$ in $e$+Au collisions using a Bayesian PDF re-weighting technique. Our studies show the EIC will be capable delivering an unprecedented measurement of charm hadron production across a broad kinematic region and will provide strong constraints to both intrinsic charm and nuclear gluon PDFs.