Off-axis Location Research Articles

Commissioning of the First MRlinac in Latin America.

To show the workflow for the commissioning of a MRlinac, and some proposed tests; off-axis targets, output factors for small fields, dose in inhomogeneities, and multileaf collimator quality assurance (MLC QA). The tests were performed based on TG-142, TG-119, ICRU 97, TRS-398, and TRS-483 recommendations as well as national regulations for radiation protection and safety. The imaging tests are in agreement with the protocols. The radiation isocenter was 0.34 mm, and for off-axis targets location was up to 0.88 mm. The dose profiles measured and calculated in treatment planning system (TPS) passed in all cases the gamma analysis of 2%/2 mm (global dose differences). The output factors of fields larger than 2 cm × 2 cm are in agreement with the model of the MRlinac in the TPS. However, for smaller fields, their differences are higher than 10%. Picket fence test for different gantry angles showed a maximum leaf deviation up to 0.2 mm. Displacements observed in treatment couch adding weight (50 kg) are lower than 1 mm. Cryostat, bridge, and couch attenuation was up to 1.2%, 10%, and 24%, respectively. The implemented tests confirm that the studied MRlinac agrees with the standards reported in the literature and that the strict tolerances established as a baseline should allow a smoother implementation of stereotactic treatments in this machine.

Conceptual design of the magnetised iron block system for the SHADOWS experiment

SHADOWS [1, 2] is an intended future beam dump experiment in the CERN North Area, aiming to search for feebly interacting particles (FIPs) [3] created in 400 GeV/c proton interactions. Due to its proposed off-axis location alongside the K12 beamline [4], the SHADOWS detector can be placed potentially very close to the beam dump, enabling it to search for FIPs in unexplored parts of the parameter space. In order to guarantee good quality of a potential signal, it is crucial to reduce any backgrounds of Standard Model particles as much as possible. The dominant background downstream the beam dump is caused by muons [1]. This introduces the need of a dedicated muon sweeping system consisting of magnetised iron blocks (MIBs) to actively mitigate this background component. We present the conceptional design studies in the framework of the Conventional Beams Working Group of the Physics Beyond Colliders Initiative at CERN [5, 6].

Do individual perceptual abilities affect speech recognition with spatial hearing aid processing?

Individuals with hearing loss experience persistent communication difficulties in noisy conditions, even with specialized hearing aid (HA) processing. Little is known about how HA processing interacts with auditory perceptual abilities required for speech-in-noise listening, possibly leading to mismatched parameters for certain listeners. We investigated how speech recognition with spatial HA processing—intended to reduce signals from off-axis locations—is affected by individual auditory perceptual abilities. 16 listeners with hearing loss completed a sentence recognition in noise task with wearable HAs in omnidirectional processing or binaural beamforming settings. On- (0°) or off-axis ( + 90°) target sentences were mixed with gender-matched two-talker maskers that were either spatially separated or co-located. The Portable Automated Rapid Testing program was used to obtain individual binaural (Spatial Release from Masking task) and monaural processing (Spectrotemporal Modulation Detection task) measures. Data show positive associations between perceptual abilities and speech recognition with omnidirectional processing across target and noise locations and negative associations with beamforming for off-axis targets in spatially separated noise. Relative associations of binaural and monaural processing abilities varied by test condition. The study has implications for individualizing spatial processing parameters in clinical HA fittings. [Work supported by NIH-K01DC018324.]

Moving Corona and the Line Profile of the Relativistic Broad Iron Emission Line

Iron fluorescence emission lines from X-ray binaries and active galactic nuclei are important diagnostic tools for studying the physical processes near the event horizon of both the stellar-mass black holes in X-ray binaries and the supermassive black holes in active galactic nuclei. In this work, we investigate the line profile of the relativistic broad iron lines from the cool accretion disk of a black hole due to the asymmetric illumination of a moving corona, which moves away from the disk with a relativistic velocity. Both the off-axis location and the radial velocity of the moving corona are considered. Our results clearly show that the illumination and the line profile are dependent on the position and velocity of the corona, since the disk region below the corona receives more flux, which is the most important factor affecting the line profiles. As expected, if the corona is close to the receding part of the rotating disk, the red peak is enhanced, while the blue peak is weakened in the broad line profile, and the central energy of the emission line is low. Conversely, if the corona is close to the approaching part of the disk, the blue peak is strong and the central energy of the emission line is high, even higher than the intrinsic energy of the emission line. Due to the beaming effect of the moving corona, the corona with high velocity illuminates the outer region of the disk, which leads to the red peak disappearing and there being only one blue peak in the profile of the emission line.

Superfast and sub-wavelength orbital rotation of plasmonic particles in focused Gaussian beams

The use of nanophotonics for optical manipulation has continuously attracted interest in both fundamental research and practical applications, due to its significantly enhanced capabilities at the nanoscale. In this work, we showed that plasmonic particles can be trapped at off-axis location in Gaussian beams assisted by surface plasmon resonance. The off-axis displacement can be tuned at the sub-wavelength scale by the incident light beams. Based on these, we propose that a superfast orbital rotation of particles in a continuous-wave laser beam can be realized in tightly focused circularly polarized Gaussian beams. The rotation has a tunable orbital radius at the sub-wavelength scale and a superfast rotation speed (more than 104 r/s in water under common laboratory conditions). Our work will aid in the development of optically driven nanomachines and find applications in micro-/nano-rheology, micro-fluid mechanics, and biological research at the nanoscale.

Ppb-level all-optical off-axis QEPAS gas sensor based on dual-wavelength demodulation of out-of-plane vibration mode

In Quartz Enhanced Photoacoustic Spectroscopy (QEPAS), due to the strained material and piezoelectric effect of the Quartz Tuning Fork (QTF), the in-plane mode of QTF is generally detected, requiring micron-scale precise and stable optical alignment and convergence. It poses a significant challenge for the use of light sources and has become a bottleneck for practical implementations of QEPAS. In this paper, a ppb-level all-optical off-axis QEPAS gas sensor based on dual-wavelength demodulation of out-of-plane mode is proposed and experimentally demonstrated. A dual-wavelength Fabry-Perot (FP) Interferometer with Ellipse Fitting-Differential Cross Multiply (EF-DCM) algorithm is designed and employed to demodulate the out-of-plane mode of off-axis QTF, which is approximately 80 times stronger than the conventional in-plane mode. This work established a novel ultra-sensitive off-axis QEPAS-based hydrogen sulfide (H2S) sensor with a 1.5 W fiber-amplified near-infrared diode laser. The minimum detection limit and normalized noise equivalent absorption of the developed H2S sensor is 74.19 ppb with 1 s integration time and 2.68 × 10−9 W∙cm−1∙Hz−1/2 respectively, beyond previously reported QEPAS-based H2S sensors. This technique effectively utilizes the out-of-plane mode of QTF and realizes the simultaneous enhancement of off-axis location and out-of-plane vibration mode detection in QEPAS, allowing a novel approach for the development of ultra-sensitive QEPAS gas sensors with notable practical application prospects.

AIROPA IV: Validating point spread function reconstruction on various science cases

We present an analysis of six independent on-sky datasets taken with the Keck-II/NIRC2 instrument. Using the off-axis point spread function (PSF) reconstruction software AIROPA, we extract stellar astrometry, photometry, and other fitting metrics to characterize the performance of this package. We test the effectiveness of AIROPA to reconstruct the PSF across the field of view in varying atmospheric conditions, number and location of PSF reference stars, stellar crowding, and telescope position angle (PA). We compare the astrometric precision and fitting residuals between a static PSF model and a spatially varying PSF model that incorporates instrumental aberrations and atmospheric turbulence during exposures. Most of the fitting residuals we measure show little to no improvement in the variable-PSF mode over the single-PSF mode. For one of the data sets, we find photometric performance is significantly improved (by ∼10 × ) by measuring the trend seen in photometry as a function of off-axis location. For nearly all other metrics we find comparable astrometric and photometric precision across both PSF modes, with a ∼13 % smaller astrometric uncertainty in variable-PSF mode in the best case. We largely confirm that the spatially variable PSF does not significantly improve the astrometric and other PSF fitting residuals over the static PSF for on-sky observations. We attribute this to unaccounted instrumental aberrations that are not characterized through afternoon adaptive optics (AO) bench calibrations.

Comparison of 126 MeV antiproton and proton—a FLUKA-based microdosimetric approach

Objective. This study aims at comparing dosimetric parameters of 126 MeV antiprotons and protons using microdosimetric approach. Approach. Microdosimetric distributions of 126 MeV proton and antiproton beams at 1 μm site size are calculated using the Monte Carlo-based FLUKA code. The distributions are calculated at various depths along the central axis in water phantom as well as at different off-axis locations. The study also includes calculations of secondary radiations produced by antiprotons and protons. Mean quality factor, is calculated using the ICRP 60 and ICRU 40 recommendations. The Relative Biological Effectiveness (RBE) of HSG tumour cell at 10% survival level is calculated based on Microdosimetric Kinetic Model. Main results. and RBE for antiprotons are higher by a factor of about 3.60, 3.41 and 1.24, respectively, at Bragg-peak and higher by a factor of about 1.41, 1.76 and 1.05, respectively, at plateau region of depth-dose profile when compared to protons. At 15 cm depth along the central axis, and RBE for protons are higher by a factor of about 1.42, 1.66 and 1.26, respectively, when compared to antiprotons. At the off-axis distance (Ld ) of 6 cm (at 11.5 cm depth in water), and of protons are higher than that of antiproton whereas the trend is opposite at off-axis distance of 4 cm. At Ld = 4 cm (at 11.5 cm depth in water), RBE of antiprotons is higher by about 4% than protons whereas at Ld = 6 cm, RBE of protons is higher by about 13% than antiprotons. Significance. The study shows that antiproton radiotherapy is advantageous as compared to protons considering enhancements in the absorbed dose and RBE-weighed dose values at the Bragg-peak.

Experimental and numerical damage characterization of glass/polypropylene multidirectional laminates under quasi-static loading condition

Polypropylene (PP) as a commodity thermoplastic, when reinforced with continuous glass fibers provides cost-effective composites. However, the low glass transition temperature and fabrication induced semi-crystalline morphology of PP set challenges for the experimental characterization especially when the quantification of damage mechanisms in multidirectional laminates is concerned. This paper is aimed at performing in-situ experimental observation, quantification and theoretical modeling of damage mechanisms in glass fiber reinforced polypropylene multidirectional laminates subjected to uniaxial quasi-static loading conditions. Two Stereo Digital Image Correlation systems (3D-DIC) are applied to measure the full-field strains and quantify the extent of damage mechanisms from the specimen's edge. The effects of ply thickness, off-axis ply orientation and location on damage initiation and growth are studied by testing different lay-ups. To validate the experimental measurements, a recent physics-based modeling technique is implemented that can predict the evolution of damage modes as well as their effects on the laminate properties. Good agreements are observed between the experimental measurements and simulation results which verify the accuracy of both analyses.

Depth resolved pencil beam radiography using AI — a proof of principle study

Aims: clinical radiographic imaging is seated upon the principle of differential keV photon transmission through an object. At clinical x-ray energies the scattering of photons causes signal noise and is utilized solely for transmission measurements. However, scatter — particularly Compton scatter, is characterizable. In this work we hypothesized that modern radiation sources and detectors paired with deep learning techniques can use scattered photon information constructively to resolve superimposed attenuators in planar x-ray imaging. Methods: we simulated a monoenergetic x-ray imaging system consisting of a pencil beam x-ray source directed at an imaging target positioned in front of a high spatial- and energy-resolution detector array. The setup maximizes information capture of transmitted photons by measuring off-axis scatter location and energy. The signal was analyzed by a convolutional neural network, and a description of scattering material along the axis of the beam was derived. The system was virtually designed/tested using Monte Carlo processing of simple phantoms consisting of 10 pseudo-randomly stacked air/bone/water materials, and the network was trained by solving a classification problem. RESULTS: from our simulations we were able to resolve traversed material depth information to a high degree, within our simple imaging task. The average accuracy of the material identification along the beam was 0.91 ± 0.01, with slightly higher accuracy towards the entrance/exit peripheral surfaces of the object. The average sensitivity and specificity was 0.91 and 0.95, respectively. Conclusions: our work provides proof of principle that deep learning techniques can be used to analyze scattered photon patterns which can constructively contribute to the information content in radiography, here used to infer depth information in a traditional 2D planar setup. This principle, and our results, demonstrate that there is information in Compton scattered photons, and this may provide a basis for further development. The work was limited by simple testing scenarios and without yet integrating complexities or optimizations. The ability to scale performance to the clinic remains unexplored and requires further study.

Searching for physics beyond the Standard Model in an off-axis DUNE near detector

Next generation neutrino oscillation experiments like DUNE and T2HK are multi-purpose observatories, with a rich physics program beyond oscillation measurements. A special role is played by their near detector facilities, which are particularly well-suited to search for weakly coupled dark sector particles produced in the primary target. In this paper, we demonstrate this by estimating the sensitivity of the DUNE near detectors to the scattering of sub-GeV DM particles and to the decay of sub-GeV sterile neutrinos (“heavy neutral leptons”). We discuss in particular the importance of the DUNE-PRISM design, which allows some of the near detectors to be moved away from the beam axis. At such off-axis locations, the signal-to-background ratio improves for many new physics searches. We find that this leads to a dramatic boost in the sensitivity to boosted DM particles interacting mainly with hadrons, while for boosted DM interacting with leptons, data taken on-axis leads to marginally stronger exclusion limits. Searches for heavy neutral leptons perform equally well in both configurations.

Detachment faulting in the Xigaze ophiolite southern Tibet: New constraints on its origin and implications

The structure and lithological sequences of ophiolites provide critical information for reconstructing their tectonic setting and thus, the history of the paleo-oceanic basins in which they formed. Our systematic mapping of three of the best-preserved massifs in the Xigaze ophiolite from the middle segment of the Yarlung Zangbo Suture Zone (YZSZ) in South Tibet, revealed a nearly intact structure of the ophiolitic sequence that has largely escaped emplacement and post-emplacement dismemberment. One of the most important results is the identification of a nearly E-W striking, serpentinized shear zone (SPSZ) preserved within the sequence. The SPSZ is rooted in the serpentinized front of the upper mantle and is mainly composed of meta-gabbroic and rodingite lenses floating in a serpentinite matrix. Extensive talc-serpentinite metasomatism, shearing and cataclastic deformation in the SPSZ reveal a complex interplay of fluid metasomatism and progressive ductile-brittle deformation in hundreds of meters of shear zone between the mantle and the crust. The structural and petrological features of the SPSZ are very similar to those of detachment faults within modern in situ oceanic core complexes (OCCs) in the Mid-Atlantic Ridge and the Southwest Indian Ridge. Zircon UPb ages from the footwall of the fault, and the age of radiolarian chert overlying it suggest that the detachment faulting took place between ca. 125 to 123 Ma. Combined with the stratigraphic and geochronological relationships between the ophiolite and the overlying sediments, we suggest that the Xigaze ophiolite developed in the supra-subduction zone on the southern margin of the Lhasa terrane during rollback of the Neo-Tethyan oceanic slab. Recognition of detachment faulting in the Xigaze ophiolites, along with other features, suggest that the Xigaze ophiolite formed at a spreading ridge, whereas the other large ultramafic massifs in YZSZ, may have formed in an off-axis location on the slow-spreading ridge.

Base Curve of Progressive Addition Lenses Influences Clear Vision and Stereopsis Area.

PurposeProgressive addition lenses (PAL) are effective, particularly for middle-aged and elderly people who require reading spectacles. However, with PALs, peripheral vision may be distorted and blurred because of both the lateral bending of the surface and the effect of unequal bending of the light coming from an off-axis location in the tangential and sagittal directions, which may lead to a decrease in the quality of vision. Till date, no evaluation of PALs has been reported with regard to peripheral and binocular vision. We investigated the influence of high-base-curve PAL on the visual function of binocular vision using a synoptophore.MethodsThe subjects were seven males and 13 females aged 50–79 years with a best-corrected visual acuity of decimal visual acuity (1.0) or higher in both eyes and addition power of 1.50–2.50 diopters as the inclusion criteria. The study design was a two-group, two-period crossover trial. Using a synoptophore, the subjective clear vision area of monocular vision and stereopsis area of binocular vision were measured while wearing conventional-base curve PAL (4-curve) and high-base-curve PAL (8-curve). HOYALUX RF SPORT 1.6 lenses (HOYA Corporation, Tokyo, Japan) were used for the test PALs.ResultsThe clear vision area of monocular vision was significantly wider when wearing the 8-curve PAL on the temporal side of the right eye (P = 0.02), and on the temporal side of the left eye (P = 0.01). The stereopsis area of binocular vision was significantly wider in all directions when wearing the 8-curve PAL: right (P = 0.02); left (P = 0.03); right 15° upward (P = 0.02); and left 15° upward (P = 0.02).ConclusionIt was clarified that, compared to 4-curve PAL, clear vision and stereopsis areas are wider when wearing 8-curve PAL.

Characterizing scales of sedimentary heterogeneity in a fluvial—estuarine reservoir analog: An example from the Mulichinco Formation, Neuquén Basin, Argentina

An integrated stratigraphic, sedimentological and petrophysical analysis is presented to document the variety of sedimentary heterogeneities scales that can occur in a fluvial–estuarine reservoir analog. In this context, outcrops of the Mulichinco Formation (Neuquén Basin, Argentina) were investigated combining architectural analysis, vertical and lateral facies organization, and reservoir properties distributions in different channel-body types. Six main facies associations have been defined: gravelly–sandy to sandy braided channels, meandering channels, floodplain deposits, tidally influenced terminal channels, and subtidal to intertidal plains deposits, which we interpret the deposition in a proximal to distal fluvial and inner estuarine systems. Sequence stratigraphic analysis suggest the fluvial–estuarine succession evolved from a lower to an upper interval representative of low to high accommodation versus sediment supply ratios, respectively. Variations in accommodation and spatial changes from on-to off-axis locations within the fluvial system might performed as large-scale controls in stratigraphic and spatial variations of channel-deposits proportions and connectedness, which decreases vertically and horizontally towards the N and SE. Moreover, these trends could be overprinted by the avulsion influence. Distribution and preservation-style of fines within the channels define different intra-channel-body compartments controlled by distinct allogenic and autogenic processes. Cross-bedded sandstones represent the facies with the greatest reservoir quality, but they record the widest range in petrophysical values and textural variations, which represent unfavourable potential facies-scale reservoir compartments and barriers. Finally, variations in cement mineralogy would be the first-order control for permeability distribution and reservoir quality separation throughout the different channel units, since clay-rich cements contain the highest values of microporosity and permeability. Therefore, primary depositional processes followed by diagenesis strongly controlled the sandstone properties as reservoir. This work provides a characterization for stratigraphic-to pore-scale sedimentary heterogeneities and may contribute to the improvement of predictive models for exploration and development strategy of fluvial–inner estuarine reservoirs.

Design of a focused collimator for proton therapy spot scanning using Monte Carlo methods.

When designing a collimation system for pencil beam spot scanning proton therapy, a decision must be made whether or not to rotate, or focus, the collimator to match beamlet deflection as a function of off-axis distance. If the collimator is not focused, the beamlet shape and fluence will vary as a function of off-axis distance due to partial transmission through the collimator. In this work, we quantify the magnitude of these effects and propose a focused dynamic collimation system (DCS) for use in proton therapy spot scanning. This study was done in silico using a model of the Miami Cancer Institute's (MCI) IBA Proteus Plus system created in Geant4-based TOPAS. The DCS utilizes rectangular nickel trimmers mounted on rotating sliders that move in synchrony with the pencil beam to provide focused collimation at the edge of the target. Using a simplified setup of the DCS, simulations were performed at various off-axis locations corresponding to beam deflection angles ranging from 0° to 2.5°. At each off-axis location, focused (trimmer rotated) and unfocused (trimmer not rotated) simulations were performed. In all simulations, a 4cm water equivalent thickness range shifter was placed upstream of the collimator, and a voxelized water phantom that scored dose was placed downstream, each with 4cm airgaps. Increasing the beam deflection angle for an unfocused trimmer caused the collimated edge of the beamlet profile to shift 0.08-0.61mm from the baseline 0° simulation. There was also an increase in low-dose regions on the collimated edge ranging from 14.6% to 192.4%. Lastly, the maximum dose, , was 0-5% higher for the unfocused simulations. With a focused trimmer design, the profile shift and dose increases were all eliminated. We have shown that focusing a collimator in spot scanning proton therapy reduces dose at the collimated edge compared to conventional, unfocused collimation devices and presented a simple, mechanical design for achieving focusing for a range of source-to-collimator distances.

Simple Analytical Approximate Formulation for the Shielding Effectiveness of a Metallic Panel With Apertures

The present paper is proposing a methodological approach for predicting the Shielding Effectiveness (SE) of metallic walls with various apertures, supported by software simulations. First, the SE modeling for a single aperture is addressed, whereas, at the difference with an homogeneous barrier, the transmission through a slot of given length behaves as a dipole that re-radiates some of the incident RF power. Because of this, the re-radiated field behind the barrier -hence the SE- becomes dependent of the barrier-to-target distance. Next, the SE for a single row of apertures is addressed, with an attempt for quantifying its dependency upon N identical holes and their individual separation. A further step is treating the SE for an array of NxM holes, including the effect of an off-axis shift target location. Some of the simulation results are compared with those obtained by using a few, widely-used simple formulae, trying to characterize their limitations, and proposing correction factors as the discrepancy typically increase with the barrier-to-target distance.

Location effect and adjustment scheme of the translation-tilt compensation bench for accelerometer performance investigation

A low-frequency vibration insensitive accelerometer test pendulum bench based on translation-tilt compensation for testing a high precise accelerometer has been proposed in order to suppress the effect of seismic noise. However, the seismic noise suppression could be affected by the high-frequency coupling due to possible nonlinearities and the cross-coupling due to the off-axis location of the accelerometers on the bench. In this paper, based on the basic vibration insensitive design and actual application requirement, the location effect of the accelerometer on the bench is firstly modeled and analyzed, and then the adjustment schemes combined with the center of percussion concept to suppress these coupling effects are presented. Finally, the analytical result and the adjustment scheme are verified by an experimental demonstration.

Roles of driven current locations on ETB and ITB based on three-field bifurcation concept

This work investigates the roles of external current source on the formation and effectiveness of an internal transport barrier (ITB) and an edge transport barrier (ETB) in fusion plasma using bifurcation approach. Thermal, particle and toroidal momentum transport equations are solved simultaneously for the spatiotemporal profiles of plasma pressure, density and toroidal velocity, respectively. The transport effects include neoclassical and turbulent terms with constant coefficients assumption. The turbulent suppression, leading to intrinsic formation of transport barriers, is driven by the magnetic shear and the flow shear. Residual stress effect is included in this work. Thermal, particle and torques sources are locally provided based on Gaussian shape distribution at plasma center, plasma edge and plasma center, respectively. The effects of off-axis driven current locations on ITB and ETB formations are investigated. In particular, width and height of ETB and ITB are shown to be affected by the source. It is found that off-axis of driven current can increase plasma temperature, density and toroidal velocity at its core because ITB is formed and expanded. However, size of ETB pedestal is slightly affected by the location of driven current. When the location of driven current is changed from r = 0.00 to 0.60, ITB width changes from r = 0.00 to 0.12 of plasma profile and ITB top formation location changes from r = 0.00 to 0.80.

Toroidal effect on runaway vortex and avalanche growth rate

The momentum-space dynamics of runaway electrons in a slab geometry, in terms of both the geometry and topological transition of the runaway vortex when synchrotron radiative damping is taken into account, has recently been shown to play a crucial role in runaway mitigation and avoidance. In a tokamak geometry, magnetic trapping arises from parallel motion along the magnetic field that scales as 1/R in strength with R the major radius. Since the transit time for a runaway electron moving along the field is of order 10−8 s while the collisional time is of ∼0.01 s in ITER-like plasmas, a bounce-averaged formulation can drastically reduce computational cost. Here, the Los Alamos Plasma Simulation – Relativistic Fokker-Planck Solver code's implementation of a bounce-averaged relativistic Fokker-Planck model, along with the essential physics of synchrotron radiation damping and knock-on collisions, is described. It is found that the magnetic trapping can reduce the volume of the runaway vortex as the momentum-space fluxes are strongly modified inside the trapped-region. As a result, the avalanche growth rate is reduced at off-axis locations. In addition to benchmarking with previous calculations that did not take into account radiation damping, we also clarify how synchrotron radiation damping modifies the avalanche growth rate in a tokamak.

A new world-class deep-water play-type, deposited by the syndepositional interaction of turbidity flows and bottom currents: The giant Eocene Coral Field in northern Mozambique

Abstract The discovery of the super-giant Coral and Mamba gas fields in the offshore of Northern Mozambique provides a unique insight into the architecture of a new deep-water play-type. High-quality seismic and extensive well data from both fields shows that very clean (clay matrix-poor) sandstone reservoirs, with thickness >100 m and extended over tens of km can be formed by the syndepositional interaction of down-slope high-density turbulent gravity flows and across-slope bottom currents. This is recorded by: i) the marked asymmetry of submarine channels and lateral stacking in which top-of-fan seismic reflectors show a lateral transition from high to low amplitude response from axis to off-axis locations; ii) the occurrence of laterally-deviated lobe deposits, sediment waves and channel-associated drifts in the inferred bottom current direction; iii) the presence of very clean sandstones forming the bulk of the fan units and the consistent lack of interbedded fine-grained facies; iv) the occurrence of fine-grained and thin-bedded facies adjacent to the main fan axes, which are characterized by repeated transitions between ripples and parallel-laminated sandstones, mud-drapes, shale clasts and bi-directional cross-laminae in the same bed, indicating intense traction and velocity pulsations. This association forms a mixed depositional system, in which only the basal and coarse-grained part of the turbidity current load is deposited and preserved in the axial part of the system, whilst all the finer-grained sediments are pirated from the turbulent cloud by laterally flowing bottom currents and deposited in the adjacent sediment drifts. The inferred process results in exceptionally high quality reservoirs whose architectural and facies models were confirmed by the appraisal campaign and production well tests and incorporated into the reservoir model. The results of this study indicate a significant exploration potential in similar geological settings and the definition of a potential new play type, that could lead to the reinterpretation of existing deep-water datasets.