Budker INP & NSU, Novosibirsk, Russia
NSU, Novosibirsk, Russia
BINP SB RAS, Novosibirsk, Russia
BINP & NSTU, Novosibirsk, Russia
At Budker Institute of Nuclear Physics it was proposed and developed a source of epithermal neutrons based on a tandem accelerator with vacuum insulation and a lithium target for the development of boron neutron capture therapy, a promising method for treating malignant tumors. To measure the "boron" dose due to the boron-lithium reaction, a small-sized detector has been developed. It consists of two polystyrene scintillators, one of which is enriched with boron. Using the detector, the spatial distribution of boron dose and dose of gamma radiation in a 330x330x315 mm water phantom was measured and the results obtained were compared with the results of numerical simulation of the absorbed dose components in such a tissue-equivalent phantom. It is shown that the results obtained are in good agreement with the calculated ones. It was found that the use of a 72 mm Plexiglas moderator provides an acceptable quality of the neutron beam for in vitro and in vivo studies, namely: 1 mA 2.05 MeV proton beam on a lithium target provides a dose rate of 30 Gy-Eq/h in cells containing boron at a concentration of 40 ppm, and 6 Gy-Eq/h in cells without boron. The developed technique for on-line measurement of boron dose and dose of gamma radiation makes it possible to carry out a similar verification of a neutron beam prepared for clinical trials of BNCT after placing a neutron beam shaping assembly with a magnesium fluoride moderator in a bunker adjacent to the accelerator.
BINP SB RAS, Novosibirsk, Russia
Epithermal neutron source based on an electrostatic tandem accelerator of a new type - Vacuum Insulation Tandem Accelerator, and lithium neutron target has been proposed and developed at BINP* for Boron Neutron Capture Therapy** - promising method for treatment of tumors. 2 MeV proton beam was obtained in the accelerator, the neutron generation carried out with bombardment of a lithium target by protons, successful experiments on irradiation of cell cultures incubated in boron medium have been carried out, human glioblastoma grafted mice were cured. It is necessary to increase proton energy from 2 to 2.3 MeV to form a neutron beam suitable for the treatment of deep-seated tumors. It is necessary to provide the high-voltage strength of the accelerator at the potential of 1.2 MV in order to suppress dark currents to an acceptably small value. Two upgrades to obtain the required potential were consistently implemented. At first, the glass rings of the feedthrough insulator were replaced by ceramic ones doubled in height which made it possible to refuse placing the resistive divider inside. Then the smooth ceramic rings were replaced by the new ceramic rings with a ribbed outer surface. Modernization made it possible to obtain the required voltage of 1.15 MV and the proton beam current of 9 mA in the accelerator without breakdowns. The report describes in detail the modernizations carried out, presents the results of the studies, and declares the research plans.
* S. Taskaev. Phys. Part. Nucl. 46 (2015) 956-990. doi: 10.1134/S1063779615060064
** Neutron Capture Therapy: Principles and Applications. Eds.: W. Sauerwein et al. Springer, 2012.
BINP SB RAS, Novosibirsk, Russia
BINP, Novosibirsk, Russia
For the development of a promising method for the treatment of malignant tumors - boron neutron capture therapy - the accelerator-based epithermal neutron source has been proposed and created in the Budker Institute of Nuclear Physics. Argon ions formed during stripping of a beam of negative hydrogen ions to protons are accelerated and, in parallel with the proton beam, are transported along the high-energy beam line of the facility. Depending on the relative number of argon ions, their effect can vary from negligible to significant, requiring their suppression. In this work, the current of argon ions reaching the beam receiver in the horizontal high-energy beam line of the accelerator was measured. It was determined that the argon beam current accompanying the proton beam is 2000 times less than the proton beam current. This makes it possible not to apply the proposed methods of its suppression.
BINP SB RAS, Novosibirsk, Russia
Budker INP & NSU, Novosibirsk, Russia
The accelerator-based epithermal neutrons source, proposed and created in the Budker Institute of Nuclear Physics, provides the generation and formation of a neutron flux suitable for testing the boron neutron capture therapy of malignant tumors. The paper presents and discusses the results of studies using activation techniques. Using activation foils from the SWX-1552 kit (Shieldwerx, USA), an iterative grid method for reconstructing the neutron spectrum was tested. It was found that the use of activation foils for determining the spectrum of epithermal neutrons is questionable, since the main part of the interaction falls on the high-energy part of the spectrum, instead of the resonance of the foil. The number of neutrons is equal to the number of activated beryllium-7 nuclei (it has been proven by measurements that beryllium-7 is not sputtered from the lithium layer). The neutron yield was monitored by registering gamma quanta from the 7Li(p, n)7Be reaction. Depending on the number of registered gamma quanta, recalculation was made for the amount of activated beryllium. In this paper it was measured the number of neutrons depending on different geometries, different parameters of the proton beam and target material, there is a good agreement with the theory.
Budker INP & NSU, Novosibirsk, Russia
NSU, Novosibirsk, Russia
BINP SB RAS, Novosibirsk, Russia
BINP, Novosibirsk, Russia
For the development of boron neutron capture therapy - an accelerator source of epithermal neutrons has been proposed and created at the Budker Institute of Nuclear Physics (Novosibirsk, Russia). For future therapy it is necessary to ensure the transportation of a proton beam in a high-energy beam line at a distance of 10 meters. For this purpose, using a movable diaphragm with a diameter of 1 mm, mounted on a three-dimensional vacuum manipulator, and a wire scanner, the phase portrait of the proton beam was measured. The software for remote control of the movable diaphragm and data processing of the wire scanner was developed. An algorithm for processing a series of measurements was developed to reconstruct the image of the phase portrait of the beam and calculate the emittance. This work describes in detail the features of the measuring devices, control algorithms and data processing. An experiment was carried out to measure the phase portrait and emittance of a proton beam with an energy of 2 MeV and a current of up to 3 mA. A beam of neutral particles was also measured. The effect of a bending magnet on the focusing and emittance of the beam is studied. The invariant normalized emittances calculated from the measured phase portraits make it possible to assert that the beam can be transported over distances of about 10 meters without changes in the current geometry of the high-energy beam line.
BINP SB RAS, Novosibirsk, Russia
BINP, Novosibirsk, Russia
For the development of a promising method for the treatment of malignant tumors - boron neutron capture therapy - the accelerator-based epithermal neutron source has been proposed and created in the Budker Institute of Nuclear Physics. If the parameters of the proton beam change (energy and current of the beam, the parameters of the ion-optical system, the parameters of the ion source) - accordingly the conditions for the beam transportation change (its size, angular divergence, and position relative to the axis of the accelerator). For optimal conduction of the beam along the beam line, two-dimensional tomography of the beam can be used: using a cooled diaphragm with a diameter of several millimeters installed on a vacuum three-dimensional motion input and a Faraday cup, fast chord measurements are carried out, on the basis of which the beam profile is restored. The beam profile obtained by this way is somewhat different from the profile obtained by measuring the phase portrait of the beam using a wire scanner*. The advantage of this method is a relatively short time to restore the profile, depending on the diameter of the cooled diaphragm.
* M. Bikchurina, at al. Measurement of the phase portrait and emittance of the proton beam and neutral atoms in the accelerator based epithermal neutrons source. These proceedings.
BINP SB RAS, Novosibirsk, Russia
Budker INP & NSU, Novosibirsk, Russia
BINP, Novosibirsk, Russia
For the development of a promising method for the treatment of malignant tumors - boron neutron capture therapy - the accelerator-based epithermal neutron source has been proposed and created in the Budker Institute of Nuclear Physics. After the acceleration phase, a proton beam with an energy of up to 2.3 MeV and a current of up to 10 mA is transported in a high-energy beam line. With a beam size of 1 cm2, its power density can reach tens of kW/cm2. Diagnostics of the size of such a powerful beam is a nontrivial task aimed at increasing the reliability of the accelerator. The paper presents such diagnostics as: 1) the use of the blister formation boundary during the implantation of protons into the metal; 2) the use of thermocouples inserted into the lithium target; 3) the use of the melting boundary of the lithium layer when it is irradiated with a beam; 4) the use of the activation of the lithium target by protons; 5) the use of video cameras; 6) the use of an infrared camera; 7) the use of the luminescence effect of lithium when it is irradiated with protons; 8) the use of collimators with a small diameter of 1-2 mm; 9) the use of the method of two-dimensional tomography*.
* M. Bikchurina, et al 2D tomography of the proton beam in the vacuum-insulated tandem accelerator. These proceedings.
BINP SB RAS, Novosibirsk, Russia
Budker INP & NSU, Novosibirsk, Russia
NSU, Novosibirsk, Russia
Epithermal neutron source based on an electrostatic tandem accelerator of a new type - Vacuum Insulation Tandem Accelerator, and lithium neutron target has been proposed and developed at Budker Institute of Nuclear Physics for Boron Neutron Capture Therapy - promising method for treatment of tumors and for other applications. The paper proposes and implements a flexible and customizable method of operational data processing, allowing researchers to obtain and analyze information directly in the experiment without the need for post-processing data. Its use accelerates the process of obtaining informative data during experimental research and automates the analysis process. Also proposed and implemented a process of automatic distributed journaling of the results of the experiment. As a result of the implementation of the proposed tools increased the productivity of the analysis of experimental data and the detailing of the experimental journal. The developed and implemented system of real-time data processing has shown its effectiveness and has become an integral part of the control system, data collection and data storage of the epithermal neutron source.
BINP SB RAS, Novosibirsk, Russia
Budker INP & NSU, Novosibirsk, Russia
NSU, Novosibirsk, Russia
Budker Institute of Nuclear Physics, Novosibirsk, Russia
A compact accelerator-based neutron source has been proposed and created at the Budker Institute of Nuclear Physics in Novosibirsk, Russia. An original vacuum insulated tandem accelerator (VITA) is used to provide a proton/deuteron beam. As a result of scientific research and modernization, the power of the ion beam was increased, an operation mode without high-voltage breakdowns was achieved, and the operation of the accelerator in a wide range of changes in the energy and current of ions was ensured. The proton/deuteron beam energy can be varied within a range of 0.6-2.3 MeV, keeping a high-energy stability of 0.1%. The beam current can also be varied in a wide range (from 0.3 mA to 10 mA) with high current stability (0.4%). VITA is used to obtain epithermal neutrons for the development of boron neutron capture therapy, thermal neutrons for the determination of impurities in ITER materials by activation analysis method; fast neutrons for radiation testing of materials; 478 keV photons to measure the 7Li(p, p’g)7Li reaction cross section, etc. VITA is planned to be used for boron imaging with monoenergetic neutron beam, for characterizing of neutron detectors designed for fusion studies, for in-depth investigation of the promising 11B(p, alfa)alfa alfa neutronless fusion reaction, for studying the crystal structure of materials by neutron diffraction, etc.
