Journal of Instrumentation

The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10³⁴ cm⁻² s⁻¹ (10²⁷ cm⁻² s⁻¹). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4π solid angle. Forward sampling calorimeters extend the pseudorapidity coverage to high values (|η| ⩽ 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.

This paper introduces a novel track-length extension fitting algorithm for measuring the kinetic energies of inelastically interacting particles in liquid argon time projection chambers (LArTPCs). The algorithm finds the most probable offset in track length for a track-like object by comparing the measured ionization density as a function of position with a theoretical prediction of the energy loss as a function of the energy, including models of electron recombination and detector response. The algorithm can be used to measure the energies of particles that interact before they stop, such as charged pions that are absorbed by argon nuclei. The algorithm's energy measurement resolutions and fractional biases are presented as functions of particle kinetic energy and number of track hits using samples of stopping secondary charged pions in data collected by the ProtoDUNE-SP detector, and also in a detailed simulation. Additional studies describe the impact of the dE/dx model on energy measurement performance. The method described in this paper to characterize the energy measurement performance can be repeated in any LArTPC experiment using stopping secondary charged pions.

The Large Hadron Collider (LHC) at CERN near Geneva is the world's newest and most powerful tool for Particle Physics research. It is designed to collide proton beams with a centre-of-mass energy of 14 TeV and an unprecedented luminosity of 10³⁴ cm⁻² s⁻¹. It can also collide heavy (Pb) ions with an energy of 2.8 TeV per nucleon and a peak luminosity of 10²⁷ cm⁻² s⁻¹. In this paper, the machine design is described.

Timepix4 is a 24.7 × 30.0 mm² hybrid pixel detector readout ASIC which has been designed to permit detector tiling on 4 sides. It consists of 448 × 512 pixels which can be bump bonded to a sensor with square pixels at a pitch of 55 µm. Like its predecessor, Timepix3, it can operate in data driven mode sending out information (Time of Arrival, ToA and Time over Threshold, ToT) only when a pixel has a hit above a pre-defined and programmable threshold. In this mode hits can be tagged to a time bin of <200 ps and Timepix4 can record hits correctly at incoming rates of ∼3.6 MHz/mm²/s. In photon counting (or frame-based) mode it can count incoming hits at rates of up to 5 GHz/mm²/s. In both modes data is output via between 2 and 16 serializers each running at a programmable data bandwidth of between 40 Mbps and 10 Gbps. The specifications, architecture and circuit implementation are described along with first electrical measurements and measurements with radioactive sources. In photon counting mode X-ray images have been taken at a threshold of 650 e⁻ (with <10 masked pixels). In data driven mode images were taken of ToA/ToT data using a ⁹⁰Sr source at a threshold of 800 e⁻ (with ∼120 masked pixels).

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 16 × 16 × 26 m³ with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.

The international collaboration designing and constructing the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) has developed a two-phase strategy toward the implementation of this leading-edge, large-scale science project. The 2023 report of the US Particle Physics Project Prioritization Panel (P5) reaffirmed this vision and strongly endorsed DUNE Phase I and Phase II, as did the European Strategy for Particle Physics. While the construction of the DUNE Phase I is well underway, this White Paper focuses on DUNE Phase II planning. DUNE Phase-II consists of a third and fourth far detector (FD) module, an upgraded near detector complex, and an enhanced 2.1 MW beam. The fourth FD module is conceived as a "Module of Opportunity", aimed at expanding the physics opportunities, in addition to supporting the core DUNE science program, with more advanced technologies. This document highlights the increased science opportunities offered by the DUNE Phase II near and far detectors, including long-baseline neutrino oscillation physics, neutrino astrophysics, and physics beyond the standard model. It describes the DUNE Phase II near and far detector technologies and detector design concepts that are currently under consideration. A summary of key R&D goals and prototyping phases needed to realize the Phase II detector technical designs is also provided. DUNE's Phase II detectors, along with the increased beam power, will complete the full scope of DUNE, enabling a multi-decadal program of groundbreaking science with neutrinos.

The RD53 collaboration has since 2013 developed new hybrid pixel detector chips with 50 × 50 μm² pixels for the HL-LHC upgrades of the ATLAS and CMS experiments at CERN. A common architecture, design and verification framework has been developed to enable final pixel chips of different sizes to be designed, verified and tested to handle extreme hit rates of 3 GHz/cm² (up to 12 GHz per chip) together with an increased trigger rate of 1 MHz and efficient readout of up to 5.12 Gbits/s per pixel chip. Tolerance to an extremely hostile radiation environment with 1 Grad over 10 years and induced SEU (Single Event Upset) rates of up to 100 upsets per second per chip have been major challenges to make reliable pixel chips. Three generations of pixel chips, and many specific mixed signal building blocks and radiation test chips, have been submitted and extensively tested to get to final production chips. The large, complex and high rate pixel chips have been developed with a strong emphasis on low power consumption together with a concurrent development and qualification of novel serial powering at chip, module and system level, to minimize detector material budget.

The high-luminosity phase of LHC operations (HL-LHC), will feature a large increase in simultaneous proton-proton interactions per bunch crossing up to 200, compared with a typical leveling target of 64 in Run 3. Such an increase will create a very challenging environment in which to perform charged particle trajectory reconstruction, a task crucial for the success of the ATLAS physics program, and will exceed the capabilities of the current ATLAS Inner Detector (ID). A new all-silicon Inner Tracker (ITk) will replace the current ID in time for the start of the HL-LHC. To ensure successful use of the ITk capabilities in Run 4 and beyond, the ATLAS tracking software has been successfully adapted to achieve state-of-the-art track reconstruction in challenging high-luminosity conditions with the ITk detector. This paper presents the expected tracking performance of the ATLAS ITk based on the latest available developments since the ITk technical design reports.

The High-Luminosity upgrade of the Large Hadron Collider, HL-LHC, will triple the proton-proton collision rate, posing challenging requirements for the ATLAS trigger and readout system. A low-latency, FPGA-based hardware trigger for muons in the barrel region will be implemented to identify candidates within 390 ns from collisions for further refinement by the Monitored Drift Tubes Trigger Processor. The upgrade of the ATLAS detector for the HL-LHC foresees the installation of an additional layer of Resistive Plate Chamber detectors and the replacement of the current trigger and readout electronics. This will allow ATLAS to keep a high efficiency for single-muon triggers with transverse momentum above 20 GeV and for multi-muon triggers, without any rate increase compared to the current system, despite the higher collision rate. The ATLAS barrel muon trigger system for the HL-LHC and the latest tests performed toward being ready for HL-LHC operations are here described.

ICARUS is the largest Liquid Argon Time Projection Chamber (LArTPC) in operation and serves as the Far Detector of the Short Baseline Neutrino (SBN) program at Fermilab. It aims to investigate the possible existence of sterile neutrinos with Δm² ≈ 1 eV² using the Booster Neutrino Beam (BNB) and explore physics beyond the Standard Model with the Neutrinos at the Main Injector (NuMI) beam. The ICARUS light detection system, comprising 360 TPB-coated large-area Photo-Multiplier Tubes (PMTs), is crucial for triggering and event reconstruction. Due to its shallow installation, the detector is exposed to a high flux of cosmic rays, necessitating precise timing to reject background events and align neutrino interactions with the beam time profile. This talk will detail the timing inter-calibration procedures for the ICARUS light detection system, which achieve sub-nanosecond resolution. Additionally, the performance of the system in reconstructing the timing of neutrino interactions from the BNB and NuMI beams will be discussed. The results highlight the effectiveness of the ICARUS light detection system in enhancing the detector's capability for precise and reliable neutrino selection.

Neutrinoless double-beta decay is a nuclear decay, given as (A,Z) → (A,Z + 2) +2e^-, with deep consequences for the understanding of our universe. A strong experimental program is underway to search for this transition with many proposed experiments using different technologies. In this article the LEGEND experiment, which uses ⁷⁶Ge as the isotope of interest, will be described. We will discuss both the first stage, LEGEND-200, which is now taking data at the Laboratori Nazionali del Gran Sasso of INFN in Italy, and the future stage, LEGEND-1000. LEGEND-200 has analyzed a first sample of data (48.3 kg·yr) collected from March 2023 to February 2024 with a background index not far away from its goal of 2×10^-4 cnts/(keV·kg·yr). Combining the LEGEND-200 data with those of Gerda and Majorana Demonstrator one obtains a sensitivity on the half-life of 0νββ decay in ⁷⁶Ge of T_1/2 > 2.8 × 10²⁶ yr at 90% C.L. and a limit on T_1/2 > 1.9 × 10²⁶ yr at 90% C.L.

The upcoming ATLAS Phase II upgrade mandates replacing the tracking system with the all-silicon Inner Tracker (ITK), featuring a pixel detector as its core element. The monitoring data of the new system will be aggregated from an on-detector ASIC, Monitoring Of Pixel System (MOPS), and channeled to the Detector Control System (DCS) via a newly developed FPGA-based interface known as MOPS-Hub. This work evaluates the MOPS-Hub FPGA's susceptibility to Single-Event Upsets (SEUs) through proton irradiation tests. An SEU rate of  7 upsets/day is estimated in the ITK radiation environment. To enhance fault tolerance and system resilience, mitigation techniques — including Triple Modular Redundancy (TMR) and using Soft Error Mitigation (SEM) IP — are implemented and assessed.

Ever more precise time information is required to separate independent events at planned and proposed particle physics experiments. Typically, a combination of internal gain, very fast amplifiers and complex sampling circuitry are used to achieve this high time resolution, which usually come at the price of additional power consumption, layout area and complexity. In this contribution a novel circuit to improve the time resolution of a Depleted Monolithic Active Pixel Sensor (DMAPS) is presented. Its amplifier feedback is designed such that within its dynamic range the time walk of the trailing edge of the amplifier is compensated, making it the better estimate of the time of arrival (ToA). At moderate layout cost, this circuit allows reduce the power consumption of the analogue front end and enables a simple time walk correction which can be implemented on the ASIC.

Particle identification (PID) is one of the main strengths of the ALICE experiment at the LHC. It is a crucial ingredient for detailed studies of the strongly interacting matter formed in ultrarelativistic heavy-ion collisions. ALICE provides PID information via various experimental techniques, allowing for the identification of particles over a broad momentum range (from around 100 MeV/c to around 50 GeV/c). The main challenge is how to combine the information from various detectors effectively. Therefore, PID represents a model classification problem, which can be addressed using Machine Learning (ML) solutions. Moreover, the complexity of the detector and richness of the detection techniques make PID an interesting area of research also for the computer science community. In this work, we show the current status of the ML approach to PID in ALICE. We discuss the preliminary work with the Random Forest approach for the LHC Run 2 and a more advanced solution based on Domain Adaptation Neural Networks, including a proposal for its future implementation within the ALICE computing software for the upcoming LHC Run 3.

A fast wave interferometer (FWI), which can measure ion mass density, has been developed on DIII-D for its use on future fusion reactors, as well as for the study of ion behavior in current plasma devices. The frequency of the fast waves used for the FWI is around 60 MHz, and require antennas and coaxial cables or waveguides, which, unlike traditional mirror-based optical interferometers, are less susceptible to neutron/gamma-ray radiation and are relatively immune to impurity deposition and erosion as well as alignment issues. The bulk ion density evaluated using FWI show good agreement with that derived from CO₂ interferometry within about 15%. When the ion mass density measurement by FWI is combined with an electron density measurement from CO₂ interferometry, Z_eff measurements are also enabled and are in agreement with those from visible Bremsstrahlung measurements. Additionally, large-bandwidth FWI measurements clearly resolve 10–100 kHz coherent modes and demonstrate its potential as a core fluctuation diagnostic, sensitive to both magnetic and ion density perturbations.

KM3NeT (Cubic Kilometer Neutrino Telescope) is a research infrastructure that comprises two underwater neutrino detectors located at different sites in the Mediterranean Sea: KM3NeT-Fr (ORCA) (offshore the coast of Toulon, France, at a depth of around 2500 m) and KM3NeT-It (ARCA) (off Capo Passero, Sicily, Italy, at a depth of around 3500 m). The experiment consists of vertical structures, called strings, along which the optical modules are positioned. A hydrophone, located on the base of each string, is used for the reconstruction of the position of the KM3NeT elements with an accuracy of 10 cm. The presence of acoustic sensors in an underwater environment gives the opportunity to detect and study the sound emissions of marine mammals present in the area. The presented work describes the identification programs of the signals emitted by dolphins (clicks and whistles) and sperm whales (clicks) and the results of the analysis of real data collected between spring 2020 and spring 2021.

The Tracking Ultraviolet Set-up (TUS) is the world's first orbital imaging detector of Ultra High Energy Cosmic Rays (UHECR) and it operated in 2016–2017 as part of the scientific equipment of the Lomonosov satellite. The TUS was developed and manufactured as a prototype of the larger project K-EUSO with the main purpose of testing the efficiency of the method for measuring the ultraviolet signal of extensive air shower (EAS) in the Earth's night atmosphere. Despite the low spatial resolution (∼5 × 5  km² at sea level), several events were recorded which are very similar to EAS as for the signal profile and kinematics. Reconstruction of the parameters of such events is complicated by a short track length, an asymmetry of the image, and an uncertainty in the sensitivity distribution of the TUS channels. An advanced method was developed for the determination of event kinematic parameters including its arrival direction. In the present article, this method is applied for the analysis of 6 EAS-like events recorded by the TUS detector. All events have an out of space arrival direction with zenith angles less than 40°. Remarkably they were found to be over the land rather close to United States airports, which indicates a possible anthropogenic nature of the phenomenon. Detailed analysis revealed a correlation of the reconstructed tracks with direction to airport runways and Very High Frequency (VHF) omnidirectional range stations. The method developed here for reliable reconstruction of kinematic parameters of the track-like events, registered in low spatial resolution, will be useful in future space missions, such as K-EUSO.

We review the current status of liquid noble gas radiation detectors with energy threshold in the keV range, which are of interest for direct dark matter searches, measurement of coherent neutrino scattering and other low energy particle physics experiments. Emphasis is given to the operation principles and the most important instrumentation aspects of these detectors, principally of those operated in the double-phase mode. Recent technological advances and relevant developments in photon detection and charge readout are discussed in the context of their applicability to those experiments.

The High-Luminosity upgrade of the Large Hadron Collider, HL-LHC, will triple the proton-proton collision rate, posing challenging requirements for the ATLAS trigger and readout system. A low-latency, FPGA-based hardware trigger for muons in the barrel region will be implemented to identify candidates within 390 ns from collisions for further refinement by the Monitored Drift Tubes Trigger Processor. The upgrade of the ATLAS detector for the HL-LHC foresees the installation of an additional layer of Resistive Plate Chamber detectors and the replacement of the current trigger and readout electronics. This will allow ATLAS to keep a high efficiency for single-muon triggers with transverse momentum above 20 GeV and for multi-muon triggers, without any rate increase compared to the current system, despite the higher collision rate. The ATLAS barrel muon trigger system for the HL-LHC and the latest tests performed toward being ready for HL-LHC operations are here described.

Neutrinoless double-beta decay is a nuclear decay, given as (A,Z) → (A,Z + 2) +2e^-, with deep consequences for the understanding of our universe. A strong experimental program is underway to search for this transition with many proposed experiments using different technologies. In this article the LEGEND experiment, which uses ⁷⁶Ge as the isotope of interest, will be described. We will discuss both the first stage, LEGEND-200, which is now taking data at the Laboratori Nazionali del Gran Sasso of INFN in Italy, and the future stage, LEGEND-1000. LEGEND-200 has analyzed a first sample of data (48.3 kg·yr) collected from March 2023 to February 2024 with a background index not far away from its goal of 2×10^-4 cnts/(keV·kg·yr). Combining the LEGEND-200 data with those of Gerda and Majorana Demonstrator one obtains a sensitivity on the half-life of 0νββ decay in ⁷⁶Ge of T_1/2 > 2.8 × 10²⁶ yr at 90% C.L. and a limit on T_1/2 > 1.9 × 10²⁶ yr at 90% C.L.

Ever more precise time information is required to separate independent events at planned and proposed particle physics experiments. Typically, a combination of internal gain, very fast amplifiers and complex sampling circuitry are used to achieve this high time resolution, which usually come at the price of additional power consumption, layout area and complexity. In this contribution a novel circuit to improve the time resolution of a Depleted Monolithic Active Pixel Sensor (DMAPS) is presented. Its amplifier feedback is designed such that within its dynamic range the time walk of the trailing edge of the amplifier is compensated, making it the better estimate of the time of arrival (ToA). At moderate layout cost, this circuit allows reduce the power consumption of the analogue front end and enables a simple time walk correction which can be implemented on the ASIC.

At REXEBIS, a higher electron current density accelerates charge breeding and allows for increased repetition rate and ion throughput of the REX-ISOLDE system, while also extending the physics reach towards very short-lived radioactive ions. This goal was pursued by introducing a non-adiabatic electron gun. Since then, further breeding characterization experiments have been carried out, focusing on reaching very high charge states for light ions, such that a closed-shell configuration with exceptionally high breeding efficiency is attained, and to lower the mass-to-charge ratio for heavy elements thereby alleviating the required acceleration gradient in the room-temperature section of the LINAC. The results are discussed and extensively compared with predictions from the ebisim charge breeding simulation code. In order to explain discrepancies in the charge breeding efficiency and an apparent excessive electron current density for heavy elements, the effect of applying different electron-ion impact ionisation models was investigated, as well as contributions from collisional excitation followed by auto-ionisation.

The use of a new optoelectronic readout chain with  (100)ps time resolution is a major milestone in the development of RICH detectors for environments with a high number of particle interactions per bunch crossing, such as the High-Luminosity LHC. A prototype chain, based on MAPMT and SiPM photon sensors coupled to readout electronics integrating the FastIC ASIC and a TDC-in-FPGA, is presented. The FastIC is an 8-channel ASIC for analogue-to-digital conversion with 25 ps time resolution. This ASIC is the predecessor of the FastRICH ASIC for the LHCb RICH upgrades. The signals from the photon detectors are timestamped in a custom multi-channel TDC-in-FPGA designed using a multi-phase clock sampling architecture with an average bin width of 150 ps. The prototype optoelectronic readout chain was tested in a charged particle beam of 180 GeV/c hadrons at the CERN SPS facility. The reference time-of-arrival of the particle tracks was measured with about 100 ps time resolution and the number of tracks per event was registered using a particle tracking system. The single-photon time resolution of the MAPMT sensors is extracted using a binned method in order to correct for the calibrated TDC bin widths and detector time-walk. The resulting best estimate of  σ = 182 ± 24 ps is in agreement with pulsed-laser measurements in the lab and consistent with the expectations from the manufacturer.

For fast neutron sources, such as compact neutron generators, it is desirable to have knowledge and ideally directly measure the energy spectrum of the generated neutrons. For neutrons, the produced radiation field, and the neutron energy spectrum, at a specific location from the source, can be altered by the distance to the source and become even significantly distorted by surrounding material — e.g. walls and the floor of the laboratory. To achieve this goal, we make use of the Time-of-Flight (ToF) technique, which has been implemented on the Timepix3 detector operated in highly integrated readout electronics as a miniaturized radiation camera MiniPIX-Timepix3. Equipped with a silicon sensor, the Timepix3 ASIC chip provides fast timing response of individual pixels at the nanosecond level. In this work, we use two Timepix3 detectors with a silicon sensor of thickness 300 μm and a segmented neutron conversion mask, intended for both thermal and fast neutrons and with a 65 μm thick silicon carbide (SiC) sensor. Demonstration and evaluation of the technique are provided by measurements with a compact neutron D-T pulsed generator at VSB-TU Ostrava laboratory which produces mono-energetic 14 MeV neutrons.

In preparation of the operation of the CMS electromagnetic calorimeter (ECAL) barrel at the High Luminosity Large Hadron Collider (HL-LHC) the entire on-detector electronics will be replaced. The new readout electronics comprises 12240 very front end (VFE), 2448 front end (FE) and low voltage regulator (LVR) cards arranged into readout towers (RTs) of five VFEs, one FE and one LVR card. The results of testing one RT of final prototype cards at CERN's CHARM mixed field facility and PSI's proton irradiation facility are presented. They demonstrate the proper functioning of the new electronics in the expected radiation conditions.

The CBM experiment uses a free streaming DAQ with interaction rates up to 10MHz resulting in data rates, which exceed storage capabilities, necessitating online processing. The SPADIC ASIC of the CBM-TRD provides hit messages with oscilloscope-like sampling of the detector data, encoding valuable information. To speed up data unpacking and computing time, feature extraction is moved to the readout FPGA. In the mCBM experiment this approach is tested, demonstrating the benefits of HLS and C++ template programming for algorithm development. Results show resolution improvements and significant reductions in data volume and unpacking speed at the computing cluster.

The RD50-MPW prototypes are High Voltage-CMOS (HV-CMOS) pixel chips in the 150 nm technology from LFoundry S.r.l. aimed at developing monolithic silicon sensors with excellent radiation tolerance, fast timing resolution and high granularity for tracking applications in future challenging experiments in physics. RD50-MPW4, the latest prototype within this programme, implements significant improvements for a high breakdown voltage (> 400 V), and therefore an excellent radiation tolerance, through a multi-ring structure around the chip edge and substrate backside-biasing to high voltage. Fabricated samples have been irradiated with neutrons up to 10¹⁶ n_eq/cm² high fluence. Measured current-to-voltage characteristics and pixel equalisation with trimming Digital-to-Analogue Circuits (DACs), to prepare for a test beam with irradiated samples, are presented.

New tungsten X-ray spectral lines were observed using the X-ray Crystal Spectrometer (XCS) system on the Experimental Advanced Superconducting Tokamak (EAST), with wavelengths ranging from 3.90 Å to 3.98 Å. Preliminary analysis suggests that these previously unidentified lines are emitted by W⁴³⁺, W⁴⁴⁺ and W⁴⁵⁺. To further validate these observations, this study utilizes the Flexible Atomic Code (FAC) and FLYCHK codes to calculate the emission spectra and ion charge-state distributions, respectively. Strong agreement between theoretical calculations and experimental observations confirms the accuracy of the spectral identification.