Track Length Research Articles

Measuring the Beam Energy in Proton Therapy Facilities Using ATLAS IBL Pixel Detectors

The accurate measurement of the beam range in the frame of quality assurance (QA) is a requirement for clinical use of a proton therapy machine. Conventionally used detectors mostly estimate the range by measuring the depth dose distribution of the protons. In this paper, we use pixel detectors designed for individual particle tracking in the high-radiation environment of the ATLAS experiment at LHC. The detector measures the deposited energy in the sensor for individual protons. Due to the limited dynamic energy range of the readout chip, several ways to measure the proton energy or range are examined. A staircase phantom is placed on the detector to perform an energy calibration relative to the NIST PSTAR stopping power database. In addition, track length measurements are performed using the detector aligned parallel with the beam axis to investigate the Linear Energy Transfer (LET) per pixel along the trajectory of individual protons. In this proof-of-principle study, we show that this radiation hardness detector can successfully be used to determine the initial proton energy for protons impinging on the sensor with an energy below 44 MeV after the range shifters. It becomes clear that an improvement of the energy resolution of the readout chip is required for clinical use.

Transport and geographic location of recreational and tourist centers as a factor in the development of tourism (on the example of Chernivtsi oblast)

The peculiarities of the transport and geographical position of Chernivtsi oblast and the possibilities of its use for the development of tourism and recreation are analyzed. The possibilities of transport connection of the region with other regions of Ukraine and foreign countries are investigated. Some aspects of the location of individual recreational and tourist centers of the region relative to the most important transport highways in the context of the transfer of tourists to the main destinations are revealed. Transport services are an integral part of the tourist product and an important factor in the development of tourism in the region. The transport accessibility of the most popular tourist facilities depends on the level of development of the transport complex, which in turn affects the price of the tourist product, its quality and the final impressions of tourists from visiting tourist places. One of the key factors affecting the development of the transport complex of the region is its transport and geographical position. The influence of this factor is first of all revealed in the location of the region relative to the main international and important national routes of communication, as well as in the distance and ease of communication from the main transport highways to the centers of recreational and tourist activity. Chernivtsi oblast, despite the size of the territory (the smallest by this indicator in Ukraine), has a favorable transport and geographical position in the context of tourism development. This is due to the following aspects: 1) A number of highways of international and national importance pass through the territory of the region, which continue in the neighboring countries – Romania and Moldova and other regions of Ukraine. The total length of public roads in the region in 2020 was 2.9 thousand km. Thus, there are more than 358 kilometers of highways per 1,000 km2 of the region’s area. 2) A fairly developed network of railway tracks has been formed in the region, within which a number of suburban and intercity railways operate. In 2020, the length of railway tracks in the region was 413 kilometers, or almost 51 km of tracks per thousand square kilometers of the region’s territory. 3) An international airport operates in Chernivtsi oblast center. This is the only facility in the region that allows air communication with other regions of Ukraine and countries of the world. Therefore, Chernivtsi oblast occupies a favorable transport and geographical position. This is primarily due to its border location and the availability of transport connections with Romania and Moldova, as well as a significant number of road and rail connections, an international airport in Chernivtsi. In general, the transport and geographical location of the main tourist and recreation centers is favorable for the development of tourism. However, the state of transport infrastructure, in particular most local roads, creates significant obstacles in the provision of quality tourist services. The most problematic aspect in this matter is the restoration of the bridge across the Prut River between the villages of Dubivtsi and Hlynnytsia. This will make it possible to significantly improve the road connection of recreational and tourist centers located in the southwestern part of the region with the M-19 and H-10 highways, which play the most important role for the arrival of tourists in the region. It is also important to increase the number of direct flights between the regions of Ukraine and with foreign countries, rail transport from Chernivtsi and to restore regular air flights.

Quantifying the impact of classification track length constraints on railway gravity hump marshalling yard performance with anylogic simulation

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Provenance analysis and thermochronology of the Chivillas Formation, Mexico: a record of basin formation and inversion in the southern Sierra Madre Oriental during the Early Cretaceous–Palaeogene

ABSTRACT Sandstone petrography, zircon and apatite U-Pb geochronology, and apatite geochemistry of Early Cretaceous siliciclastic turbidites interbedded with basalt (Chivillas Formation) in the southern Sierra Madre Oriental, Mexico, indicate local provenance from westerly basement sources. Three main detrital populations were observed in both the zircon and apatite geochronology: Meso–Neoproterozoic, Carboniferous–Permian, and Early Cretaceous. Apatite Sr/Y vs light rare earth element discrimination diagrams indicate that most Precambrian grains have affinity with high-grade metamorphic rocks and most Phanerozoic grains with igneous rocks. These results are consistent with derivation from exposed crystalline sources within the Acatlán-Oaxacan block including the Grenvillian Oaxacan Complex, the East Mexico Arc, and the Early Cretaceous continental arc. The compositional disparities observed in individual samples reflect differences in source of individual turbiditic flows comprising the Chivillas Formation. We surmise that various rivers from the northern and southern Acatlán-Oaxacan block drained into the basin during the Early Cretaceous. Furthermore, detrital apatite fission-track analyses of Chivillas sandstones yielded mostly 42–40 Ma ages (Eocene) that post-date the shortening of the Mexican orogen in the southern Sierra Madre Oriental. Thermal models calculated based on track lengths indicate rapid exhumation of Chivillas rocks at 46–36 Ma, which is the time of the development of the Tehuacán Valley and reactivation of the Oaxaca Fault System as a normal fault.

Effect of Wood Medium on Dispersion Parameters of Prefabricated Spherical Fragments in Forest

In order to study the influence of the forest environment on the killing power of prefabricated fragments, the relationship between the wood medium in the forest and the residual velocity of prefabricated fragments and a simple calculation model were obtained. The impact test of 300 mm thick pine target plate was carried out with 6 mm and 11 mm diameter tungsten alloy spherical fragments. The LS-DYNA finite element modeling of wood was carried out and compared with the experimental parameters, which verified the reliability of the numerical simulation method on the residual velocity of fragments. Based on this, a simple mathematical calculation method for the forest environment is constructed to calculate the penetration track length of fragments in the forest environment. Combined with the model and the formula for calculating the residual velocity of wood, the impact of forests on fragments within a certain radius can be evaluated. According to the characteristics of the forest environment, the boundary effects of the multi-layer spacing targets and trees were further studied. The research shows that the wood reduces the fragment power mainly by affecting the penetration length. The influence of forest density, tree diameter, and other parameters on the fragment velocity attenuation in the forest environment is analyzed. Using this method, the influence of forest environmental parameters on fragment dispersion parameters can be simply evaluated.

PO26 Presentation Time: 7:40 AM: Dosimetry Accuracy of a Model-Based Dose Calculation Algorithm in Modeling a Novel Direction Modulated Brachytherapy Tandem Applicator for the Cervical Cancer

<h3>Purpose</h3> A novel shielded tandem applicator for the direction modulated brachytherapy (DMBT) was previously introduced, which showed capability to improve the coverage of nonuniform targets and organs at risk in cervical cancer. This applicator has been recently modeled in a commercial treatment planning system (TPS - BrachyVision ACUROS^TM (BVA)), a Model based Dose Calculation algorithm (MBDCA), for the clinical research. In this study, we aim to benchmark the accuracy of the TPS in modeling the DMBT tandem using Monte Carlo (MC) simulations. <h3>Materials and Methods</h3> The DMBT tandem applicator, made of an MR compatible tungsten alloy with six symmetrical grooves covered by a sheath of PEEK plastic, was simulated in GEANT4 MC code. Subsequently, two scenarios were created using the BVA TPS and reproduced by GEANT4 MC simulations, including ‘source at the center of the water phantom' and ‘source at the middle of the applicator' for the cubical phantoms with dimensions of (20 cm)³, (30 cm)³, and (40 cm)³. A track length estimator (TLE) was then utilized to estimate the dose deposited inside the water phantoms and 2D/3D scoring were performed. Volumetric dose comparisons of the TPS against MC results were further implemented. <h3>Results</h3> There were different level of agreements between the TPS and MC results for the different phantom sizes. The best agreement, however, was achieved for the phantom (40 cm)³, such that the dose difference fell in the intervals [0% 8.5%] and [-6.5% 6.5%] in 95% of the voxels, for the ‘source at the center of the water phantom' and ‘source at the middle of the applicator', respectively. In addition, the dose difference was within for all phantoms, within 5 cm from the center of the HDR sources. <h3>Conclusions</h3> The results of this study indicated that the accuracy of the TPS in dose calculation depends on the phantom size. Nevertheless, it seems the TPS could still provide satisfactory accuracy inside the area of clinical importance.

Test of a prototype Microstrip Silicon Detector for the FOOT experiment

The FOOT (FragmentatiOn Of Target) experiment aims to measure the fragmentation cross-section of protons into H, C, O targets at beam energies of interest for hadrontherapy (50-250 MeV for H and 50-400 MeV/u for C ions).Given the short range of the fragments, an inverse kinematic approach requiring precise tracking capabilities in a magnetic volume has been chosen.A key subsystem of this experiment will be the Microstrip Silicon Detector, based on 3 X-Y measuring station, each composed of two 150 μm thick single side microstrip sensors. In this work, we present the results of characterization of the new version of a 64 channel low-noise/low power high dynamic range readout ASIC and subsequent tests of the first 150 um thick sensor prototype.A series of tests were also performed to validate a novel “grazing angle” approach, where it is possible to change the track length below a given strip varying the incoming particle’s incident angle onto the sensor to test the electronics dynamic range without using high Z ions.

FRESHWATER POTENTIAL BASED ON IDENTIFICATION OF AQUIFER LAYER IN BALANGAN COUNTY, INDONESIA

Groundwater is a reservoir of fresh water located beneath the ground surface in soil pore spaces and the fractures of lithology formations. Groundwater contained in the aquifer layer has a certain depth. Aquifer layer measurement was conducted with five tracks using the AGI Super Sting R1 IP tool with a spacing of 25 m and a track length of 675 m in Balangan County. This study aims to determine the 2D cross-sectional model, analyze lithology types, and determine the depth, thickness, and aquifer type in the study area based on the resistivity value. The results showed that the study area includes two rock formations – the Dahor and Warukin formations. The Dahor formation is clay with a resistivity value of 1–28.284 m, sandy clay 28.284–99.055 m, and sand 99.055–800 m. The Warukin formation is clay with a resistivity value of 1–10 m, sandy clay 10–31.623 m, and sand 31.623–100 m. Aquifer layer estimation shows that track 1 has a free aquifer and contains aquitard rock. Next, track 2 has a confined aquifer and contains rocks that are both aquifer and aquitard. Then, track 3 has a free aquifer type and contains rocks that are aquifer and aquitard. Track 4 has two measurements with a depressed aquifer and contains rocks that are aquifer. Finally, Track 5 has a depressed aquifer and contains aquitard rock. This study shows the existence of groundwater deposits in the thickness of the aquifer layer in Balangan County, Indonesia.

Spurious age-eU associations in thermochronological data

The He and fission-track ages of individual apatite, titanite, and zircon grains, and the Raman ages of zircon grains are often correlated with their effective uranium concentrations (eU). These correlations are thought to result from closure-temperature differences related to lattice damage from self-irradiation. We present apatite fission-track and zircon-Raman data with negative age-eU correlations even though the track lengths and the agreement between Raman bands with different annealing sensitivities rule out radiation-damage-related age differences. Age-eU plots are vulnerable to spurious correlation due to the fact that the age- and eU-estimates both depend on measurements of the parent concentration. Correlation between age and eU is thus an inescapable component of datasets in which the daughter and parent concentrations are not in fixed proportion. Non-linear D-P relationships due to radiation-damage effects create true age-eU correlations, whereas systematic or random deviations from proportionality lead to spurious correlations. Plotting the daughter against parent concentrations (D-P plot) helps to distinguish causal and spurious age-eU associations. Some cases are inconclusive, for example when similar causal and spurious effects combine to form the age-eU trend, but a significant number is less ambiguous. Apart from detecting spurious correlations, D-P plots can be used for validating causal age-eU associations by corroborating the D-P relationships predicted by radiation-damage models for specific thermal histories. Suspected causal age-eU correlations should also be backed up by evidence of differential annealing such as fission-track-length or multi-band Raman measurements.

Effect of treatment zone on the performance of polyurethane-stabilized ballast under cyclic loading

In current study the effect of treatment zone on the performance of polyurethane stabilized ballast layer was examined under cyclic loading conditions. Test results reveal that the deformation and degradation response of ballast is significantly dependent on the depth of ballast treated with polyurethane. For a given treatment depth, the ballast samples treated only beneath the sleeper and those with treatment all along the track length has undergone similar extent of deformations and degradation. On the other hand, with the increase in treatment depth from top 75 mm of ballast (i.e. one-fifth of ballast depth) to 380 mm (full depth of ballast layer), the lateral spread reduction index (LSRI) was found to increase significantly. Further, it is evident that the polyurethane has significantly reduced the vertical stresses and improved resilient and damping characteristics of ballast. It is seen that the track stiffness (k) of all PSB samples was significantly higher than that of unstabilized ballast (USB) sample. The track life enhancement factor (Lef) defined the ratio of number of load cycles (N) required to attain the designated strains in case of stabilized ballast and unstabilized ballast is found to vary from 2000 to 60 for 0.4 % volumetric strain. The performance ranking of different PSB samples is given based on the track stiffness per unit of polyurethane used. The current study recommends the treatment of top half of ballast layer but only beneath the sleeper as it was found to be effective in improving the performance of ballast.

Characterization of a low-pressure Micro-Megas-like gaseous detector with low energy x-ray sources

Within the family of the Micro Strip Gas Detectors (MSGD), the intrinsic characteristics of the bulk Micro-Megas (MM) device represent the most promising features for the construction of a new instrument to be operated as a TPC gas chamber in a low-pressure regime. In this study, we present the main properties of a low-pressure bulk MM detector in which the amplification gap was slightly increased to improve the gas gain. Two configurations have been deeply studied: the first one with a gap of 128μm and a second one with a 192μm gap, both filled and operated with a gas mixture (Ar-CO2) at pressures below 100 mbar. The dependence of the gain and the energy resolution on the amplification field, gas pressure and drift field have been evaluated. The reliability of the measured performance, combined with the simple and robust structure of the detector even with an increased length of amplification gap, make it an attractive choice for applications where the track length of low energy particles is detected by using a low-pressure filling gas.

Prospects for the Development of Intermodal Transport in the Visegrad Countries, Germany and Italy - Selected Aspects

The article presents the results of research on the possibilities of developing intermodal rail transport in the Visegrad Group countries, Italy and Germany. The research was conducted based on statistical data regarding demand for transport in intermodal cargo units and rail transport. Selected elements of transport infrastructure were taken into account as well, i.e. the length of railway tracks and railway lines (including electrified ones), the railway line density indicator, and the number of terminals. The study results proved that there was a noticeable development of infrastructure in Hungary which makes it a prospective market, affording the possibility for development of domestic and international transport. The biggest decrease for railway transport was observed in Germany and Poland. In the same time, in Poland there was observed the biggest increase in demand for intermodal container units (ICUs). The inverse relationship between demand for railway transport and ICUs is observed in most countries. Only in Czechia there was a parallel increase observed. It has been observed that linear and point infrastructure requires investment in electrification in most countries surveyed. These investments are important due to handling the needs of foreign trade. With the growing demand for transport and developed infrastructure, the intermodal rail transport will be able to compete with road transport. This process is consistent with the need to ensure green transport and modify transport structure into the environmental friendly one.

Оценка экономической эффективности проекта модернизации технологий электрификации железнодорожного участка

Purpose: To evaluate the economic efficiency of contact network modernization project for the railway section of the St. Petersburg - Baltiyskaya power supply distance of the Oktyabrskaya Railway (OR). The study subject is the operation protocol for contact network modernization. Methods: Analysis basic methods are applied — target indicator statistical analysis of electrified section specific weight in the total operational length of public railway tracks; target indicator statistical analysis of railway line electrification. Results: The modernization of electrification technologies on the railway section of “St. Petersburg-Baltiyskiy” OR railway distance is justified. Implementation main stages for contact network modernization project are systematized. Economic effect being obtained from electrification technologies modernization is determined. Practical importance: The obtained results represent an applied character since they propose and justify measure series aimed at servicing effectiveness raise for the railway section servicing of the St. Petersburg-Baltiyskiy OR railway power supply distance.

Proton 3D tracking and emission time from a short-lived isomer with ACTAR TPC

An experiment was conducted at the GANIL/LISE3 facility to produce the 10+ isomer of 54Ni and measure its proton radioactivity decay branches. The proton detection was achieved with the ACTAR TPC device that enabled the separation of the small signal of the emitted proton from the large signal of the implanted ion, while the decay half-life is of the order of 150 ns. From the measured data, the emitted proton track length and the decay time of the ion can be extracted simultaneously. The full proton radioactivity pattern could be established, with two emission branches and their relative branching ratio. Data processing and analysis that allowed to identify and separate the ion and the proton signals in order to reconstruct the particles trajectories and decay time are detailed. The evaluation of the detection efficiency for the proton radioactivity branches based on a full simulation is described.

An exploratory study of machine learning techniques applied to therapeutic energies particle tracking in microdosimetry using the novel hybrid detector for microdosimetry (HDM)

In this work we present an advanced random forest-based machine learning (ML) model, trained and tested on Geant4 simulations. The developed ML model is designed to improve the performance of the hybrid detector for microdosimetry (HDM), a novel hybrid detector recently introduced to augment the microdosimetric information with the track length of particles traversing the microdosimeter. The present work leads to the following improvements of HDM: (i) the detection efficiency is increased up to 100%, filling not detected particles due to scattering within the tracker or non-active regions, (ii) the track reconstruction algorithm precision. Thanks to the ML models, we were able to reconstruct the microdosimetric spectra of both protons and carbon ions at therapeutic energies, predicting the real track length for every particle detected by the microdosimeter. The ML model results have been extensively studied, focusing on non-accurate predictions of the real track lengths. Such analysis has been used to identify HDM limitations and to understand possible future improvements of both the detector and the ML models.

Network Planning for Innovative Track-Based Transportation Technologies: A Minimum Spanning Tree Algorithm to Demonstrate Network Benefits

Direct connectivity, the main principle of developing the Interstate highway system, is of reduced importance for track-based transport networks. Ultra-speed, enabled by innovative technologies, can transport passengers via indirect links fast enough that certain direct links can be strategically removed to achieve cost savings while maintaining target transit times. Few studies have investigated such network benefits associated with ultra-speed technologies, and the relationship of vehicle speed, track length, and travel time savings is not well understood. Therefore, this article quantifies the relationship by studying potential transport networks using a case study in the American Midwest. A graph-theory-based heuristic algorithm is proposed to generate the optimal network and a set of scenarios are analyzed to test the sensitivity of network benefits to speed. Results show that ultra-speed can reduce the total length of the transport network by almost 50% while offering over 50% travel time reduction. This first attempt at quantifying the network benefits sheds light on transport network planning and infrastructure project development by mitigating the problems of capital cost and land acquisition.

Analysis of the least mean squares algorithm with reusing coefficient vector

The coefficient reuse strategy is able to improve the steady-state performance of adaptive filter algorithms, especially in very challenging low signal-to-noise scenarios. This paper advances deterministic and stochastic models that predict various learning characteristics of the LMS algorithm with coefficient reuse. First-order and second-order analyzes are derived for the sufficient order case and then extended for the tracking and deficient length scenarios. An exact expectation analysis, which does not employ the ubiquitous independence assumption, is presented for a particular configuration of the algorithm, and its results suggest that, except in the first phase of the learning process, the decay in mean-square deviation of the coefficient vector is governed by an almost-sure theoretical analysis. The simulation results confirm the equations obtained in the theoretical analysis.

Loop track: an infinite long track model

ABSTRACT This paper developed a track model called the ‘Loop Track’ that had a new function to simulate infinite long tracks without heavy data movement. The model was three-dimensional and considers rails, sleepers, ballast, subballast, and subgrade. Rails were modelled by using the Finite Element Method whilst all other components were modelled as equivalent rigid bodies connected by flexible force elements. The loop or infinite feature of the model was achieved by adding an extra boundary section to link the last node set to the first node set of the original track model. Case studies were conducted to simulate infinite long tracks and variable track conditions, as well as to determine the minimum track length required for different simulations. Results show that the recommended minimum track lengths for the simulated cases were 76 sleepers for vertical track dynamics and 301 sleepers for longitudinal track dynamics.

Fast beta-emitter Monte Carlo simulations and full patient dose calculations of targeted radionuclide therapy: introducing egs_mird.

Targeted radionuclide therapy (TRT) is a fast-growing field garnering much interest, with several clinical trials currently underway, that has a steady increase in development of treatment techniques. Unfortunately, within the field and many clinical trials, the dosimetry calculation techniques used remain relatively simple, often using a mix of S-value calculations and kernelconvolutions. The common TRT calculation techniques, although very quick, can often ignore important aspects of patient anatomy and radionuclide distribution, as well as the interplay there-in. This paper introduces egs_mird, a new Monte Carlo (MC) application built in EGSnrc which allows users to model full patient tissue and density (using clinical CT images) and radionuclide distribution (using clinical PET images) for fast and detailed dose TRT calculation. The novel application egs_mird is introduced along with a general outline of the structure of egs_mird simulations. The general structure of the code, and the track-length (TL) estimator scoring implementation for variance reduction, is described. A new egs++ source class egs_internal_source, created to allow detailed patient-wide source distribution, and a modified version of egs_radionuclide_source, changed to be able to work with egs_internal_source, are also described. The new code is compared to other MC calculations of S-values kernels of 131 I, 90 Y, and 177 Lu in the literature, along with further self-validation using a histogram variant of the electron Fano test. Several full patient prostate 177 Lu TRT prostate cancer treatment simulations are performed using a single set of patient DICOM CT and [18 F]-DCFPyL PETdata. Good agreement is found between S-value kernels calculated using egs_mird with egs_internal_source and those found in the literature. Calculating 1000 doses (individual voxel uncertainties of ∼0.05%) in a voxel grid Fano test for monoenergetic 500keV electrons and 177 Lu electrons results in 94% and 99% of the doses being within 0.1% of the expected dose, respectively. For a hypothetical 177 Lu treatment, patient prostate, rectum, bone marrow, and bladder dose volume histograms (DVHs) results did not vary significantly when using the TL estimator and not modeling electron transport, modeling bone marrow explicitly (rather than using generic tissue compositions), and reducing activity to voxels containing partial or full calcifications to half or none, respectively. Dose profiles through different regions demonstrate there are some differences with model choices not seen in the DVH. Simulations using the TL estimator can be completed in under 15 min (∼30 min when using standard interaction scoring). This work shows egs_mird to be a reliable MC code for computing TRT doses as realistically as the patient Computed Tomography (CT) and Positron Emission Tomography (PET) data allow. Furthermore, the code can compute doses to sub-1% uncertainty within 15 min, with little to no optimization. Thus, this work supports the use of egs_mird for dose calculations inTRT.

A Probabilistic Particle Tracking Framework For High Particle Densities

A framework for particle tracking velocimetry at high particle densities (HD-PTV) based on a Gaussian Mixture Model (GMM) is presented. This new approach is validated by tracking synthetic particles generated for a generalized turbulent pipe flow defining the ground truth. For a step size per time step of δS = 14 px and a particles per pixel (ppp) density of 0.09 the framework tracks about 90% of the ground truth particles (percentage of matched particles, pmp) already after 9 time steps without generating any ghost particles. For a lower step size of δS = 7 px, corresponding to a higher temporal resolution of the flow, and the lowest investigated particle density ppp = 0.02 a constant pmp close to 100% is reported. A decrease on pmp to 80% is found for the highest ppp = 0,11 - corresponding to about 45000 particles in total. Increasing the step size per time step to δS = 14 px results in a similar sloping curve and pmp that are generally 5% lower compared to the lower step size. The approach is further successfully applied to a well-known experimental tracking problem, i.e. particle tracking in turbulent Rayleigh-Bénard convection, for which the motion of about 28500 particles is tracked. With track lengths up to 250 times steps the occuring structures and velocities are investigated and agree well with previous studies based on tomographic particle image velocimetry using the same data. Thus, it is concluded that the presented HD-PTV framework is an appropriate tool for the flow analysis even at high particle densities.