Vladimir Bashkirov

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Determination of the Bragg peak position in proton therapy requires accurate knowledge of the electron density and ratio of effective atomic number and mass (Z/A) of the body tissues traversed. While the Z/A ratio is fairly constant for human tissues, the density of tissues varies significantly. One possibility to obtain accurate electron density(More)
—Proton computed tomography (pCT) has the potential to improve the accuracy of dose calculations for proton treatment planning, and will also be useful for pretreatment verification of patient positioning relative to the proton beam. A design study was performed to define the optimal approach to a pCT system based on specifications for applications in(More)
Conformal proton radiation therapy requires accurate prediction of the Bragg peak position. Protons may be more suitable than conventional x-rays for this task since the relative electron density distribution can be measured directly with proton computed tomography (CT). However, proton CT has its own limitations, which need to be carefully studied before(More)
PURPOSE The authors present a calibration method for a prototype proton computed tomography (pCT) scanner. The accuracy of these measurements depends upon careful calibration of the energy detector used to measure the residual energy of the protons that passed through the object. METHODS A prototype pCT scanner with a cesium iodide (CsI(Tl)) crystal(More)
–As part of a program to investigate the feasibility of proton computed tomography, the most likely path (MLP) of protons inside an absorber was measured in a beam experiment using a silicon strip detector setup with high position and angular resolution. The locations of 200 MeV protons were measured at three different absorber depth of PMMA (3.75, 6.25 and(More)
  • Zeus Collaboration, J Breitweg, +415 authors W B Schmidke
  • 2007
Exclusive production of 0 and J== mesons in e + p collisions has been studied with the ZEUS detector in the kinematic range 0:25 < Q 2 < 50 GeV 2 , 20 < W < 167 GeV for the 0 data and 2 < Q 2 < 40 GeV 2 , 50 < W < 150 GeV for the J== data. Cross sections for exclusive 0 and J== production have been measured as a function of Q 2 , W and t. The spin-density(More)
Assuming that the number of ionizations events within short segments of DNA-size volumes is a major factor of the biological effectiveness of ionizing radiation, we have designed and manufactured a new nanodosimetric detector counting ionization events in small wall-less gas volumes, which simulate such DNA segments. The detector measures individual(More)
Using the ZEUS detector at HERA, we have studied the reaction e + p ! e + X for Q 2 > 5000 GeV 2 with a 20:1 pb ?1 data sample collected during the years 1994 to 1996. For Q 2 below 15000GeV 2 , the data are in good agreement with Standard Model expectations. For Q 2 > 35000 GeV 2 , two events are observed while 0:145 0:013 events are expected. A(More)
In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample(More)
  • Zeus Collaboration, J Breitweg, +407 authors W B Schmidke
  • 2007
The e + p neutral-current deep inelastic scattering diierential cross-sections dd=dQ 2 , for Q 2 > 400 GeV 2 , dd=dx and dd=dy, for Q 2 > 400, 2500 and 10000 GeV 2 , have been measured with the ZEUS detector at HERA. The data sample of 47.7 pb ?1 was collected at a center-of-mass energy of 300 GeV. The cross-section, dd=dQ 2 , falls by six orders of(More)