Biological Dose Estimation Model for Proton Beam Therapy

Purpose: The recommended value for the relative biological effectiveness (RBE) of proton beams is currently assumed to be 1.1. However, there is increasing evidence that RBE increases towards the end of proton beam range that may increase the biological effect of proton beam in the distal regions of the dose deposition. Methods: A computational approach is presented for estimating the biological effect of the proton beam. It includes a method for calculating the dose averaged linear energy transfer (LET) along the measured Bragg peak and published LET to RBE conversion routine. To validate the proposed method, we have performed Monte Carlo simulations of the pristine Bragg peak at various beam energies and compared the analysis with the simulated results. A good agreement within 5% is observed between the LET analysis of the modeled Bragg peaks and Monte Carlo simulations. Results: Applying the method to the set of Bragg peaks measured at a proton therapy facility we have estimated LET and RBE values along each Bragg peak. Combining the individual RBE-weighted Bragg peaks with known energy modulation weights we have calculated the RBE-weighted dose in the modulated proton beam. The proposed computational method provides a tool for calculating dose averaged LET along the measured Bragg peak. Conclusions: Combined with a model to convert LET into RBE, this method enables calculation of RBE-weighted dose both in pristine Bragg peak and in modulated beam in proton therapy

Energy degrader optimization for medical beam lines

This paper describes the optimization of a variable energy degrader design for the Midwest Proton Radiotherapy Institute (MPRI) [1]. To optimize the energy degrader design we investigate the choice of an optimal material for the degrader, the beam emittance growth in the degrader, and the matching of the degraded beam with the acceptance of a medical beam line.Comment: Submitted to Nucl.Inst.Meth. Sec.

Построение сложных опционных стратегий с учетом предпочтений инвестора. Приложение

Popularity of investment of means in the share market steadily increases. Therefore, there is a demand of design of various financial products, leaning on objective and desires of the investor. Practical realization of construction complex опционных strategy in view of preferences of the investor is resulted

Учет расчетов по налогу на прибыль на примере ООО «ПРОФИ ТДСК»

В работе рассмотрены теоретические основы формирования прибыли. Рассмотрены особенности образования и налогообложения прибыли в жилищном строительстве на примере ООО "Профи ТДСК".In the article theoretical bases of formation of profit. Considered features of the formation and taxation of gains in residential construction the example of OOO "Profi TDSK"

Оценка аварийных рисков при эксплуатации гидротехнического сооружения

Гидротехнические сооружения являются объектами повышенного риска, аварии на них могут привести к катастрофическим последствиям. Предприятия, имеющие на балансе гидротехнические сооружения, обязаны учитывать аварийные риски, связанные с их эксплуатацией.Hydraulic engineering structures are objects of increased risk, accidents on them can lead to catastrophic consequences. Enterprises that have hydraulic facilities on their balance sheets are obliged to take into account the emergency risks associated with their operation

Millimeter-Wave Superconducting Quantum Devices

To continue achieving ever faster computation speeds, future computer processors may need to increase their operating frequency to achieve clock speeds beyond several GHz. Quantum computing offers an alternate approach by leveraging quantum mechanical superposition to make each clock operation more efficient, allowing the processor to solve certain problems much more efficiently. Current quantum processors operate slower than their classical counterparts, with the fastest quantum operations at microwave frequencies and utilizing superconducting artificial atoms (qubits)— a promising platform for quantum experiments studying light-matter interactions in the strong coupling regime. Increasing qubit frequency to the millimeter-wave range (∼100 GHz) offers a straightforward way to increase quantum computing speed for any qubit design. Crucially, millimeter-wave frequencies also have greatly reduced sensitivity to thermal noise. Whereas microwave qubits require extremely low temperatures (< 50 mK) through isotopic enrichment of 3He and 4He in order to reduce sources of decoherence, millimeter-wave qubits can operate at significantly higher temperatures near 1 K. These temperatures are achievable using simpler methods such as 4He evaporation, which translates to orders of magnitude higher cooling power. This is transformative for scaling up superconducting quantum processors by significantly increasing the number of qubit control channels possible in a single cryostat, enabling direct integration of qubits with superconducting digital processors, and allowing for more energy efficient possibilities for quantum communication between cryostats. In this thesis, we introduce millimeter-wave superconducting devices as a platform for quantum experiments. We develop a robust niobium trilayer Josephson junction with improved quantum coherence properties capable of operating at higher frequencies and temperatures than conventional aluminum junctions. Based on this technology we explore the thermal resilience of qubits with higher and higher frequency, finally demonstrating a 72 GHz millimeter-wave qubit cooled entirely with helium-4

Type-3 snakes in high energy accelerators

Several pairs of Siberian snakes are usually required to preserve the beam polarization in a high energy proton ring. It is found that installing additional type-3 snakes in the arcs of a high energy accelerator could significantly reduce local spin perturbation between snakes and thus improve overall spin stability in the ring. The best results could be obtained when a type-3 snake is installed 1/4 of the way into each arc