DEVELOPMENT OF NEW TYPE NEUTRON BEAM PROFILER/monitor FOR Cancer TISSUE INVESTIGATIONS
Project Status: 3 Approved without Funding
Duration in months: 36 months
Objective
In accordance with the goals and tasks of the ISTC within the frameworks of the present Project it is suggested to create a research group from scientists and engineers mainly of YerPhI who previously were engaged in realization of defense programs, for research and development of new type neutron flux monitors/profilers based on vibrating wire. These profilers are cheap and easy making, operates at high background noise, have precise spatial resolution, high sensitivity, high performance speed, wide range, and robustness against radiation.
It is supposed that obtained results will be used for establishment of 252Cf neutron source based station in AIP-TSU aimed to investigate biological objects (cancer tissue, blue-green algae, cyanobacteriae etc) irradiated by different doses of neutrons. The neutron station will be equipped also with shielding, dosimetry instruments, safety devices and differential scanning calorimeter. The planned investigations of biological objects will be carried out with various modern methods of biophysics, which will give a possibility to evaluate the influence of neutron irradiation on changes of structural organization of biomacromolecules at level of cells, tissues and macromolecules.
Many research centers in the world use neutrons as probes to investigate diverse properties of a wide range of materials. Neutrons have found interesting uses in medicine, both in the treatment and in the development of ultra-sensitive analytical techniques. Neutron scattering gives detailed information about atomic level structure and dynamics. Neutrons used in the scattering experiments have wavelengths similar to the atomic spacing, allowing the structures of materials to be studied by diffraction on the length scales from atomic dimensions to macromolecular scales. There are few centers specialized in neutron therapy, where neutrons are particularly generated from low energy cyclotrons. Control of the spatial distribution of the beam and its intensity in this field of usage is vital. Therefore, there is need for devices, capable of real-time aquisition of the beam intensity.
Neutron monitors are commonly used to detect mineral resources in geophysical studies, as well as in aerospace research of composition and structure of planets and asteroids (the NASA Dawn Mission). Having superior sensitivity compare to the familiar tools for measuring the parameters of neutron beams, provided sensors can be used to expand the reliability and accuracy of the analyzed data.
Neutron beam’s flux intensity in the existing neutron sources reaches to 1013-1015 n/cm2/s. The new task is to increase the intensity of the neutron beams further. Instrumentation for the neutron beams needs a variety of detectors and monitors for measurements and controls.
In this proposal for neutron beam measurements we suggest new method where used heat release of neutrons in the wire. We intend to combine two unique opportunities – the unprecedented sensitivity of the natural frequency of a clamped vibrating wire to the wire temperature, and remarkable ability of some gadolinium isotopes to the neutron capture. The 157Gd has the highest thermal neutron capture cross section of all the stable isotopes in the periodic table. We propose to measure temperature increase of the wire containing gadolinium isotopes, which occurs when neutrons penetrate the wire and deposit some energy into the wire.
So, Vibrating Wire Neutron Monitor (VWNM) with composite wires and wide dynamic range aimed to high level spatial resolution profiling of high flux and large cross-section neutron beams of specialized neutron sources (research reactors and spallation source) on the inlet of neutron based instruments will be developed. We propose to develop two types of VWNM with different scales of wire length, which defines the resolution and response time. These types will cover different dynamic ranges of neutron flux intensities and can be used in different applications from high-flux neutron beam profiling to high-speed environmental monitoring in nuclear safety field.
In the second method, we propose to use vibrating wire as a target occupied different positions in the space during the oscillation process. If the measured beam flux density varies on distances about oscillations amplitude, the difference on scattering process in extreme positions can provide information on flux gradient. For neutron beam we intend to use the same gadolinium covered vibrating wires. Difference of measurements of prompt gamma-rays arise at neutron capture in gadolinium layer in synchronism with the wire’s oscillation frequency allow to obtain exclusively the signal of capture events and discriminate usually presented homogeneous background of gamma-rays with wide spectrum of energies. This takes opportunity to use simple nonselective gamma-ray detectors. Usage of sensitive gamma-ray detectors can improve the resolution of the neutron beam profiling compared with the measurements of vibrating wire frequency changes that need considerable heating of the wire. Response time of method is defined by vibrating wire frequency and estimated of order of 1-0.1 ms. This type of monitors we call Resonant Target Vibrating wire Neutron Profiler (RT-VWNP).
Proposed Resonant target vibrating wire neutron monitors (VWNM and RT-VWNP) should be a new modification of previously developed by us vibrating wire sensors with wide dynamic range, inherent long-term stability, high precision, and resolution, good reproducibility, minimum zero drift, and small hysteresis. Usage of few simultaneously operating vibrating wires allows correspondingly increase the response speed of monitor and exclude the complicated mechanical system of scanning.
Developed as a result of project fulfillment monitors can be widely used for all applications of neutron beams. Small sizes scale VWNM with 10-100 ms response time may be used in field of nuclear safety as a portable, high-speed environmental monitor. As a portable device, VWNM can be used as radiation robust detector at neutron weapon usage. Methods uses deep penetration of neutrons into the tissue may allow to solve one of the main problem of modern oncology - early diagnosis of cancer with the reliability that is not available to other methods. Probing wells with neutron beams allows to determine the presence of mineral resources. NASA uses neutron detectors for distance investigations of the structure and composition of dwarf planets and asteroids. Therefore, to get reliable data is essential to have easy-to-use and highly sensitive detectors of neutron beams. Furthermore, they must perform reliably in harsh environments. The proposed sensors meet all of these conditions; moreover, they can be easy manufactured with low cost. Sounding neutron beams wells allows us to determine the presence of minerals, and NASA uses neutron sensors for remote study the structure and composition of small planets and asteroids. In addition, to get reliable data is essential to have easy-to-use and highly sensitive detectors of neutron beams. Furthermore, they must perform reliably in harsh environments. The proposed sensors meet all of these conditions, moreover they are easy to make, lightweight and cheap.
RT-VWNP as a reliable instrument with also excellent spatial resolution can be applied for low flux neutron beam diagnostics (e.g. for centers of neutron therapy). Specialized multiwire monitors with possibility of rotation along the beam axis can be used to recovery of complicated 2D profiles of large cross-section neutron beams in neutron tomography, imaging and radiography.
On the basis of developed monitors/profilers we intend to establish 252Cf neutron source based station in AIP-TSU aimed to investigate biological objects (cancer tissue, cancer cells, cancer whole blood, cancer blood plasma/serum, blue-green algae, cyanobacteriae etc) irradiated by different doses of neutrons. The neutron station will be equipped with shielding, dosimetry instruments, safety devices and differential scanning calorimeter.
The main tasks of the Project are following:
· Development of composite wire model for estimations of VWNM technical characteristics;
· Development of two types vibrating wire resonators sensitive to neutron fluxes and development of corresponding monitors (VWNM) for neutron flux intensity measurement and low intensity neutron beam profiling (RT-VWNP);
· Establishment of 252Cf neutron source based station equipped with VWNM and RT-VWNM in AIP-TSU aimed to investigate biological objects;
· Investigations on biological objects with usage of wide range methods of biophysics as well as by measuring the structure of interacted with tissue neutron beams by developed neutron flux monitors/profilers.
Participating Institutions
LEADING
Cosmic Ray Division (Yerevan) of Yerevan Physics Institute
PARTICIPATING
Ivane Javakhishvili Tbilisi State University/ E. Andronikashvili Institute of Physics
COLLABORATOR
Ulsan National Institute of Science and Technology
