Showing papers on "Time of flight published in 2023"

A segmented total energy detector (sTED) for (n, γ) cross section measurements at n_TOF EAR2

Abstract: The neutron time-of-flight facility n_TOF is characterised by its high instantaneous neutron intensity, high-resolution and broad neutron energy spectra, specially conceived for neutron-induced reaction cross section measurements. Two Time-Of-Flight (TOF) experimental areas are available at the facility: experimental area 1 (EAR1), located at the end of the 185 m horizontal flight path from the spallation target, and experimental area 2 (EAR2), placed at 20 m from the target in the vertical direction. The neutron fluence in EAR2 is ˜ 300 times more intense than in EAR1 in the relevant time-of-flight window. EAR2 was designed to carry out challenging cross-section measurements with low mass samples (approximately 1 mg), reactions with small cross-sections or/and highly radioactive samples. The high instantaneous fluence of EAR2 results in high counting rates that challenge the existing capture systems. Therefore, the sTED detector has been designed to mitigate these effects. In 2021, a dedicated campaign was done validating the performance of the detector up to at least 300 keV neutron energy. After this campaign, the detector has been used to perform various capture cross section measurements at n_TOF EAR2.

ToF-SIMS Depth Profiling to Measure Nanoparticle and Polymer Diffusion in Polymer Melts

Abstract: We apply time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and cross-sectioned trilayer samples to separately measure nanoparticle (NP) and polymer diffusion on micrometer length scales in polymer melts. We fabricate polymer/diffusing medium/polymer trilayer samples and measure the cross section to extract the NP or deuterated polymer distribution in 3D using ToF-SIMS. After correcting the data for sample tilt, deconvoluting the beam resolution, and integrating the data to extract 1D concentration profiles, we fit the data to extract the diffusion coefficient. These results from cross-sectional ToF-SIMS are in excellent agreement with earlier studies using well-established ion beam methods. This work establishes ToF-SIMS as a reliable tool for measuring NP and polymer diffusion coefficients and opens the door to investigating diffusion in more complex polymer systems and across longer time and length scales.

A simple retarding-potential time-of-flight mass spectrometer for electrospray propulsion diagnostics

Abstract: Abstract The time-of-flight mass spectrometer (ToF-MS) is a useful tool for quantifying the performance of electrospray thrusters and characterizing their plumes. ToF-MS data can be used to calculate the mass-to-charge distribution in the plume, but the kinetic-energy-to-charge (i.e., the potential) distribution must be known first. Here we use a ToF-MS in tandem with a retarding potential (RP) analyzer. By sweeping the retarding potential through the range of potentials present in the plume, both the mass-to-charge distribution and the potential distribution can be measured independently. We demonstrate this technique in a case study using a capillary electrospray emitter and the ionic liquid propellant 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, abbreviated EMI-Im. We report a linear correlation between retarding potential and mass-to-charge ratio that agrees with published data from more complex orthogonal RP/ToF-MS instruments. Calculated values for the jet velocity and jet breakup potential match within 2% and 12%, respectively. Using conventional ToF-MS, we estimated the propellant flow rate and compared those estimates to direct flow rate measurements. For flow rates between 233 pL/s and 565 pL/s, the error in ToF-based flow rate estimates ranged from -16% to -13% when the plume potential was assumed to be a function of mass-to-charge. Assuming a constant plume potential yielded mixed results. However, using the average stopping potential measured by a retarding potential analyzer resulted in higher errors, ranging from -26% to -30%. Data and MATLAB code are included as supplemental materials so that readers can easily apply the techniques described here.

The SNR of positron emission data with Gaussian and non-Gaussian time-of-flight kernels, with application to prompt photon coincidence

Abstract: It is well known that measurement of the time-of-flight (TOF) increases the information provided by coincident events in positron emission tomography (PET). This information increase propagates through the reconstruction and improves the signal-to-noise ratio in the reconstructed images. Takehiro Tomitani has analytically computed the gain in variance in the reconstructed image, provided by a particular TOF resolution, for the center of a uniform disk and for a Gaussian TOF kernel. In this paper we extend this result, by computing the signal-to-noise ratio (SNR) contributed by individual coincidence events for two different tasks. One task is the detection of a hot spot in the center of a uniform cylinder. The second one is the same as that considered by Tomitani, i.e. the reconstruction of the central voxel in the image of a uniform cylinder. In addition, we extend the computation to non-Gaussian TOF kernels. It is found that a modification of the TOF-kernel changes the SNR for both tasks in almost exactly the same way. The proposed method can be used to compare TOF-systems with different and possibly event-dependent TOF-kernels, as encountered when prompt photons, such as Cherenkov photons are present, or when the detector is composed of different scintillators. The method is validated with simple 2D simulations and illustrated by applying it to PET detectors producing optical photons with event-dependent timing characteristics.

A combined SiPM-based TOF+RICH detector for future high-energy physics experiments

Abstract: A novel compact particle identification (PID) detector concept based on Silicon Photomultipliers (SiPMs) optimized to perform combined Time-of-Flight (TOF) and Ring-Imaging Cherenkov (RICH) measurements using a common photosensitive sensor is under development. The system consists of a Cherenkov radiator layer separated from a photosensitive surface equipped with SiPMs by an expansion gap. A thin glass slab, acting as a second Cherenkov radiator, is coupled to the SiPMs to perform Cherenkov-based TOF measurements. We have built and tested a detector prototype including a 2 cm thick aerogel radiator and a 3 mm thick NaF slab. With a RICH resolution better than 1 mrad and a TOF resolution better than 50 ps, the present technology makes the proposed SiPM-based PID system particularly attractive for future high-energy physics experiments where space and cost constraints are critical. In this work, we discuss the principle of operation of the proposed TOF+RICH integration, with a particular focus on the optimization of the TOF radiator material, thickness and coupling with SiPMs, as well as the achievable angular and timing performance. Finally, preliminary beam test results for the considered detector prototype are presented.

Isotopic and elemental analysis by electrostatic energy analyzer laser ablated time-of-flight mass spectrometer

Abstract: In this work, we present a modified setup of the time of flight (TOF) mass spectrometer. It consists of a laser ablation source, and a Q-switched Nd:YAG laser (532 nm, 100 mJ, 7 ns) integrated with a linear TOF mass spectrometer coupled with an electrostatic energy analyzer (EEA). Ions are detected by a channeltron electron multiplier assembled with EEA. The main objective of this work is to resolve the ion’s initial energy problem and improve the reproducibility of the results. Employing this newly developed setup the elemental analysis of a known sample was performed for different laser energies and found no shift in the position of the ions signals on the time scale. In addition to elemental analysis, isotopic compositions of lithium, titanium, copper, and silver samples have been also derived. Our results are in good agreement with their natural abundance. The design parameters of the instrument were optimized. The mass calibration was achieved by measuring the flight time of various ions; Li+, Ti+, Cu+, and Ag+.

Measurement of the neutron cross section on argon between 95 and 720 MeV

Abstract: We report an extended measurement of the neutron cross section on argon in the energy range of 95–720 MeV. The measurement was obtained with a 4.3-hour exposure of the Mini-CAPTAIN detector to the WNR/LANSCE beam at LANL. Compared to an earlier analysis of the same data, this extended analysis includes a reassessment of systematic uncertainties, in particular related to unused wires in the upstream part of the detector. Using this information we doubled the fiducial volume in the experiment and increased the statistics by a factor of 2.4. We also shifted the analysis from energy bins to time-of-flight bins. This change reduced the overall considered energy range, but improved the understanding of the energy spectrum of incoming neutrons in each bin. Overall, the new measurements are extracted from a fit to the attenuation of the neutron flux in five time-of-flight regions: 140–180 ns, 120–140 ns, 112–120 ns, 104–112 ns, 96–104 ns. The final cross sections are given for the flux-averaged energy in each time-of-flight bin with statistical and systematic (syst) uncertainties: σ(146 MeV)=0.60−0.14+0.14±0.08(syst) b, σ(236 MeV)=0.72−0.10+0.10±0.04(syst) b, σ(319 MeV)=0.80−0.12+0.13±0.040(syst) b, σ(404 MeV)=0.74−0.09+0.14±0.04(syst) b, σ(543 MeV)=0.74−0.09+0.09±0.04(syst) b.4 MoreReceived 11 January 2023Accepted 8 March 2023DOI:https://doi.org/10.1103/PhysRevD.107.072009© 2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNeutron physicsParticles & Fields

Genetic Algorithm for determination of the event collision time and particle identification by time-of-flight at NICA SPD

Abstract: Particle identification is an important feature of the future SPD experiment at the NICA collider. In particular, identification of particles with momenta up to a few GeV/c by their time-of-flight will facilitate reconstruction of events of interest. High time-resolution of modern TOF detectors dictates the need to obtain the event collision time t0 with comparable accuracy. While determination of the collision time is feasible through the use of TOF signals supplemented by track reconstruction, it proves to be computationally expensive. In this work we have developed a dedicated Genetic Algorithm as a fast and accurate method to determine the pp-collision time by the measurements of the TOF detector at the SPD experiment. By using this reliable method for t0 determination we compare different approaches for the particle identification procedure based on TOF-signals.

Plastic Classification Using Optical Parameter Features Measured with the TMF8801 Direct Time-of-Flight Depth Sensor

Abstract: We demonstrate a methodology for non-contact classification of five different plastic types using an inexpensive direct time-of-flight (ToF) sensor, the AMS TMF8801, designed for consumer electronics. The direct ToF sensor measures the time for a brief pulse of light to return from the material with the intensity change and spatial and temporal spread of the returned light conveying information on the optical properties of the material. We use measured ToF histogram data of all five plastics, captured at a range of sensor to material distances, to train a classifier that achieves 96% accuracy on a test dataset. To extend the generality and provide insight into the classification process, we fit the ToF histogram data to a physics-based model that differentiates between surface scattering and subsurface scattering. Three optical parameters of the ratio of direct to subsurface intensity, the object distance, and the time constant of the subsurface exponential decay are used as features for a classifier that achieves 88% accuracy. Additional measurements at a fixed distance of 22.5 cm showed perfect classification and revealed that Poisson noise is not the most significant source of variation when measurements are taken over a range of object distances. In total, this work proposes optical parameters for material classification that are robust over object distance and measurable by miniature direct time-of-flight sensors designed for installation in smartphones.

Calibration of a Time-of-Flight Camera Using Probability and Reflection Analysis

Abstract: This paper introduces a general calibration approach for typical Time-of-Flight (ToF) depth cameras. 3D Range detection needs in various industry areas, such as machine vision, robotics, etc. are increasing. Recent advancements in microelectronics have enabled the development of more powerful ToF cameras, which provide high-quality 3D information with high frame rates. ToF camera outputs contain various error types, most of which could be classified as systematic. To get accurate 3D info, a calibration procedure that compensates for errors in range measurements is needed. In this work, we propose a novel calibration approach for the Azure Kinect Developer Kit (DK) depth camera that employs a probability-based model involving reflection analysis. A planar checkerboard pattern and a planar pattern containing gray-valued areas are used to determine depth camera calibration parameters. Evaluations are done for each pixel, and a corresponding look-up table of camera parameters is acquired. The results of the presented method at various distances are assessed, and an improvement in the accuracy of the 3D measurements of the ToF camera is achieved.

A Novel Imaging Method for Two-Tap Pulsed-Based Indirect Time-of-Flight Sensor

Abstract: This article proposes an imaging method for two-tap pulsed-based indirect time-of-flight (I-ToF) sensor, which aims to reduce the distance error and motion artifact. Compared with the conventional imaging method, the proposed imaging method adopts emitted pulse light whose width is halved and height is doubled without changing the CMOS image sensor (CIS) system. Then, by using the distance-solving method that cooperates with this timing, it achieves depth imaging with the same range of distance measurement as the conventional method. The validity of the proposed method is demonstrated by the pixel-array behavior-level model based on the actual I-ToF imaging system. The experimental results show that compared with the conventional method, the distance error and motion artifact are reduced by 29.2% and 67.4%, respectively, under 350-mW/sr light source radiation intensity, 10-klx background illumination, and 500- $\mu \text{s}$ integration time. When the above parameters are changed, the proposed method still achieves about 29.3% reduction in distance error and 67.4% reduction in motion artifact. The proposed method is compatible with other methods to further reduce the distance error and motion artifact.

The TOP counter and determination of bunch-crossing time at Belle II

Abstract: At the Belle II experiment a Time-of-Propagation (TOP) counter is used for particle identification in the barrel region. This novel type of particle identification device combines the Cherenkov ring imaging technique with the time-of-flight and therefore it relies on a precise knowledge of the time of collision in each triggered event. We discuss the performance of the counter and present a maximum likelihood based method for the determination of event collision time from the measured data.

The TORCH time-of-flight detector

Abstract: TORCH is a large-area time-of-flight (ToF) detector, proposed for the Upgrade-II of the LHCb experiment. It will provide charged hadron identification over a 2–20 GeV/c momentum range, given a 9.5 m flight distance from the LHC interaction point. To achieve this level of performance, a 15 ps timing resolution per track is required. A TORCH prototype module having a 1250×660×10 mm3 fused-silica radiator plate and equipped with two MCP-PMTs has been tested in a 8 GeV/c CERN test-beam. Single-photon time resolutions of between 70–100 ps have been achieved, dependent on the beam position in the radiator. The measured photon yields agree with expectations.

Wide field time of flight measurements of highly scattering media

Abstract: We present a setup that makes use of a time-resolved single-photon camera to determine the scattering parameters of media. The measurement is realized in a non-contact way, both for the illumination laser and for the detection. By fitting the time-of-flight acquired distributions at different spatial positions with the diffusion equation, we retrieve the scattering coefficients of a highly diffusive isotropic reference media for wavelengths in the range from 540 to 840 nm.

Time-of-Flight measurement on a rail by laser-ultrasound

Abstract: Abstract Stress states of thermal origin on the Continuously Welded Rail (CWR) are a source of possible inconvenience due to winter breakage or dangerous summer buckling. To date, alongside procedures based on the measurement of rail displacements or rail cutting, several methods for measuring the stress state in the rail have been proposed, based on X-ray diffraction, Barkhausen noise, and the acoustoelastic effect; all these approaches have some critical issues for extensive use in the field. The acoustoelastic method is based on the dependence of the ultrasonic wave speed on the stress state of the material and involves the measurement of the Time of Flight (ToF). Because of the modest acoustoelastic effect, the speed variations caused by the stress states are very limited, which is reflected in the need for ToF measurements with an accuracy of the order of a few nanoseconds. In the past, the research group successfully used the acoustoelastic method to monitor a 3 km portion of a rail between Florence and Pontassieve, with fixed measurement stations, where the ultrasonic probes were permanently positioned on the neutral axis of the rail. Today, the need is to have a mobile measuring system, which can measure in several points or even continuously as the system moves along the rail. This appears to be possible through the use of, for example, non-contact systems such as those based on laser and air-coupled probes or lasers alone. In the first case, however, the acoustic wave partly propagates in the air before reaching the piezoelectric probe, and this path is subjected to variations in temperature and thus ToF. In the second case, the ultrasonic waves are generated and detected by optical methods with lasers. For the generation of acoustic waves, the use of pulsed lasers has become a widespread, reliable practice, which allows researchers to obtain signals of high amplitude and wide bandwidth. For the reception of the acoustic signal, the precision required in the measurement involves careful analysis and experimentation to identify the most appropriate laser technique, depending on the quality of the surface on which the measurement is performed, the sensitivity of the method, and the possibility of taking measurements while moving. In the present work, a technique for laser detection of ultrasonic waves, Optical Beam Deflection (OBD), is analysed. The technique is based on the deflection of an optical beam: the beam irradiates the surface of the rail and is reflected at angles that depend on the orientation of the surface at the point of measurement, which is perturbed by the passage of the acoustic wave. The technique, developed in the 1990s, has limited applications in non-destructive testing, where interferometer-based techniques are more widespread; still, they require more sophisticated and expensive equipment. Different experimental arrangements and initial experimental results are analysed and presented, to optimise their sensitivity and verify their suitability for the purpose.

Monte Carlo analysis of the contributions of long-lived positronium to the spectra of positron-impact-induced secondary electrons measured using an annihilation-gamma-triggered time-of-flight spectrometer

Abstract: Magnetic bottle Time-of-Flight (ToF) spectrometers can measure the energy spectra of all electrons emitted into a 2π sr solid angle simultaneously, greatly reducing data collection time. When the detection of the annihilation gamma (γ) and the detection of the electron (e) are used as timing signals for ToF spectrometers, the e-γ time difference spectra (e-γ TDS) are reflective of the positron-induced electron energy distributions provided the times between the impact of the positrons and the emission of the annihilation gammas are short compared to the flight times of the electrons. This is typically the case since positrons have short lifetime in solids (∼100–500 ps) compared to the flight times of the secondary electrons (102 ns to 103 ns). However, if the positron leaves the surface as a positronium atom (a bound electron–positron state), the annihilation gamma photons can be appreciably delayed due to the longer ortho-positronium (o-Ps) lifetime. This can result in an e-γ TDS having an exponential tail with a decay constant related to the o-Ps lifetime. Here, we present an analysis of the e-γ TDS using a Monte Carlo model which estimates the spectral contributions resulting from o-Ps annihilations. By removing the contributions from the delayed gamma signal, the energy spectrum of Positron Impact-Induced Secondary electrons (PIISE) can be isolated. Furthermore, our analysis allows an estimation of the intensity of the exponential tail in the e-γ TDS providing a method to measure the fraction of positrons that form Ps at solid surfaces without relying on assumed 100 % Ps emitting surfaces for calibration.

Monte Carlo analysis of the contributions of long-lived positronium to the spectra of positron-impact-induced secondary electrons measured using an annihilation-gamma-triggered time-of-flight spectrometer

Abstract: Magnetic bottle Time-of-Flight (ToF) spectrometers can measure the energy spectra of all electrons emitted into a 2$\pi$ sr solid angle simultaneously, greatly reducing data collection time. When the detection of the annihilation gamma ($\gamma$) and the detection of the electron (e) are used as timing signals for ToF spectrometers, the e-$\gamma$ time difference spectra (e-$\gamma$ TDS) are reflective of the positron-induced electron energy distributions provided the times between the impact of the positrons and the emission of the annihilation gammas are short compared to the flight times of the electrons. This is typically the case since positrons have short lifetime in solids ($\sim$ 100 - 500 ps) compared to the flight times of the secondary electrons ($10^2$ ns to $10^3$ ns). However, if the positron leaves the surface as a positronium atom (a bound electron-positron state), the annihilation gamma photons can be appreciably delayed due to the longer ortho-positronium (o-Ps) lifetime. This can result in an e-$\gamma$ TDS having an exponential tail with a decay constant related to the o-Ps lifetime. Here, we present an analysis of the e-$\gamma$ TDS using a Monte Carlo model which estimates the spectral contributions resulting from o-Ps annihilations. By removing the contributions from the delayed gamma signal, the energy spectrum of Positron Impact-Induced Secondary electrons (PIISE) can be isolated. Furthermore, our analysis allows an estimation of the intensity of the exponential tail in the e-$\gamma$ TDS providing a method to measure the fraction of positrons that form Ps at solid surfaces without relying on assumed 100% Ps emitting surfaces for calibration.

Simultaneous time-skew and time-walk correction for TOF-PET detector

Abstract: Time-of-flight (TOF) has become a very important technology in PET, as it reduces noise to improve the PET imaging performance significantly. To obtain a high coincidence resolving time (CRT), it is effective to eliminate inter-crystal scattering (ICS). In one-to-one readout detectors, ICS events can be easily eliminated by setting an energy window for each photo sensor. Removal of ICS events improves CRT but greatly reduces sensitivity. In this work, we developed a simultaneous time-skew and time-walk correction method that suppresses the degradation of CRT even when ICS events are used for a whole-body TOF-PET scanner. A TOF detector with one-to-one readout using fast LGSO and multi pixel photo counter (MPPC) was developed to apply the proposed correction method. To maximize the sensitivity, the crystal size was 3.1 × 3.1 × 20 mm 3 and all sides were chemically polished as the surface treatment. The fast LGSO array was optically connected to an 8 × 8 MPPC array so that the crystals and MPPCs were in one-to-one coupling. In the detector calibration, we worked to improve CRT by separating individual crystal clusters into photoelectric absorption and multiple ICSs on a 2D position histogram and performing simultaneous time-skew and time-walk correction. A pair of TOF detectors was assembled and CRT was measured. When ICS events were removed as much as possible, the CRT of 230.4 ps was obtained, but about 80% of the coincidence events were removed as ICS events. On the other hand, with all events including ICS, the CRT was 320.2 ps. Using the proposed correction method, we improved the CRT to 268.5 ps without causing sensitivity loss.

Wide field time of flight measurements of highly scattering media

Abstract: We present a setup that makes use of a time-resolved single-photon camera to determine the scattering parameters of media. The measurement is realized in a non-contact way, both for the illumination laser and for the detection. By fitting the time-of-flight acquired distributions at different spatial positions with the diffusion equation, we retrieve the scattering coefficients of a highly diffusive isotropic reference media for wavelengths in the range from 540 to 840 nm.

Performance Evaluation of State-of-the-Art High-Resolution Time-of-Flight Cameras

Abstract: It has been about 20 years since the disruptive appearance of the first time-of-flight (ToF) cameras. Since then, ToF imaging has progressively evolved. Nowadays, ToF sensors have broken the barrier of the 1-megapixel resolution, and a significant number of high-resolution ToF cameras have appeared in the market. To provide a better understanding of their performance and applications, we experimentally evaluate three state-of-the-art high-resolution ToF cameras such as Azure Kinect, Helios2, and S100D, together with the solid-state LiDAR L515. We perform various experiments to examine some key parameters, such as warm-up times, accuracy, precision, lateral and axial resolutions, edge noise, unsteady scenes, and modulated waveform and optical power. Our evaluation draws various conclusions: S100D shows fluctuations within 1 mm after being powered up while the others require warm-up times. Azure Kinect, Helios2, and L515 can achieve precision within 2 mm in a measuring range of 0.5–3 m. Helios2 and S100D are more severely affected by dynamic scenes. Finally, the point clouds (PCs) generated for a white panel at a distance of 1.5 m show that flying pixels are present in all cameras, being this problem less acute for the L515.

Evaluation of a method for time-of-flight, wavelength and neutron flight path calibration for neutron scattering instruments by means of a mini-chopper and standard neutron monitors

Abstract: Abstract Accurate conversion of neutron time-of-flight (TOF) to wavelength is of fundamental importance to neutron scattering measurements in order to ensure the accuracy of the instruments and the experimental results. Equally important in these measurements is the determination of uncertainties, and with the appropriate precision. Especially in cases where instruments are highly configurable, the determination of the absolute wavelength after any change must always be performed (e.g. change of detector position). Inspired by the manner with which neutron spectrometers determine the absolute wavelength, we evaluate for the first time, in the author's knowledge, a commonly used method for converting TOF to neutron wavelength by measuring the neutron flight path length from the source of neutrons to a monitor and we proceed to analytically calculate the uncertainty contributions that limit the precision of the conversion. The method was evaluated at the V20 test beamline at the Helmholtz Zentrum Berlin (HZB), emulating the ESS source with a long pulse of 2.86 ms length and 14 Hz repetition rate, by using a mini-chopper operated at 140 Hz and two portable beam monitors (BMs), as well as accompanied data acquisition infrastructure. The mini-chopper created well-defined neutron pulses and the BM was placed at two positions, enabling the average wavelength of each of the pulses created to be determined. The used experimental setup resulted in absolute wavelength determination at the monitor positions with a δλ mean / λ mean of ∼1.8% for λ > 4 Å. With the use of a thinner monitor, a δλ mean / λ mean of ∼1% can be reached and with a modest increase of the distance between the reference monitor positions a δλ mean / λ mean of below 0.5% can be achieved. Further improvements are possible by using smaller chopper disc openings and a higher rotational speed chopper. The method requires only two neutron measurements and doesn't necessitate the use of crystals or complex fitting with sigmoid functions and multiple free variables, and could constitute a suitable addition to imaging, diffraction, reflectometers and small angle neutron scattering instruments, at spallation sources, that do not normally utilise fast choppers.

Measurement of the 241Am(n,γ) cross section at the n_TOF facility at CERN

Abstract: The neutron capture cross section of 241Am is an important quantity for nuclear energy production and fuel cycle scenarios. Several measurements have been performed in recent years with the aim to reduce existing uncertainties in evaluated data. Two previous measurements, performed at the 185 m flight-path station EAR1 of the neutron time-of-flight facility n_TOF at CERN, have permitted to substantially extend the resolved resonance region, but suffered in the near-thermal energy range from the unfavorable signal-to-background ratio resulting from the combination of the high radioactivity of 241Am and the rather low thermal neutron flux. The here presented 241Am(n,γ) measurement, performed with C6D6 liquid scintillator gamma detectors at the 20 m flight-path station EAR2 of the n_TOF facility, took advantage of the much higher neutron flux. The current status of the analysis of the data, focussed on the low-energy region, will be described here.