Researchers have made a breakthrough in the field of laser-driven neutron generation, achieving a significant increase in neutron yield and paving the way for a wide range of applications. The study, led by a team from the University of Szeged, Hungary, utilized few-cycle, relativistic laser pulses to accelerate deuterons, which then collided with a deuterated polyethylene (dPE) target to generate neutrons through the 2H(d,n)3He fusion reaction. The experiment, conducted at a repetition rate of 1 Hz, resulted in an average neutron yield of 1,142 ± 59 per laser shot, an order of magnitude higher than previously reported using kHz laser systems. This breakthrough could have significant implications in fields such as nuclear physics, medical research, material science, homeland security, and the nuclear industry.
Harnessing the Power of Few-Cycle Laser Pulses
The researchers from the University of Szeged, Hungary, have made a significant breakthrough in the field of laser-driven neutron generation. By utilizing few-cycle, relativistic laser pulses, they have achieved a remarkable increase in neutron yield, opening up new possibilities for a wide range of applications.
The Science Behind the Breakthrough
The experiment involved accelerating deuterons (heavy hydrogen nuclei) using 12-femtosecond, 21-millijoule laser pulses interacting with a 0.2-micrometer-thin deuterated polyethylene (dPE) foil. The laser was operated at a peak intensity of 1018 watts per square centimeter and a repetition rate of 1 Hz, in bursts of 75 shots.
The accelerated deuterons then collided with a secondary dPE target, generating neutrons through the 2H(d,n)3He fusion reaction. The energy and spatial distribution of the generated fast neutrons were characterized using a time-of-flight (ToF) neutron detector system.
Unprecedented Neutron Yield
The analysis of the experimental data, comprising more than 3,000 laser shots, revealed an average neutron yield of 1,142 ± 59 per laser shot. This is an order of magnitude higher than what was recently reported using kHz laser systems with pulse energies of a few millijoules.
The key factors contributing to this remarkable neutron yield include:
– The use of few-cycle, relativistic laser pulses, which can efficiently accelerate deuterons to energies suitable for fusion reactions.
– The high repetition rate of 1 Hz, enabled by the use of a rotating target wheel, allowing for a quasi-continuous source of neutrons.
– The careful design and optimization of the experimental setup, including the target configuration and the neutron detection system.
Potential Applications and Future Prospects
The high-flux, laser-driven neutron source demonstrated in this study has the potential to revolutionize various fields of research and industry. Some of the key applications include:
Nuclear Physics: The neutron source can be used for nuclear resonance spectroscopy and neutron imaging, providing valuable insights into the structure and properties of nuclei.
Medical Research: The moderation of the fast neutron spectrum to thermal and epithermal regimes can enable applications in medical research, such as neutron therapy and radioisotope production.
Material Science: The neutron source can be utilized for the study of materials under extreme conditions, including the investigation of radiation damage and the characterization of new materials.
Homeland Security: The laser-driven neutron source can be employed in the detection and identification of illicit materials, contributing to enhanced security measures.
Nuclear Industry: The neutron source has the potential to play a role in the transmutation of spent nuclear fuel and the production of medical radioisotopes, addressing important challenges in the nuclear industry.
Fig. 2
The researchers believe that their work paves the way for the development of a pulsed neutron source with a Joule-class, kHz repetition rate laser, producing an average neutron flux as high as 1010 per second. This would represent a significant advancement in the field of laser-driven neutron generation and open up even more exciting possibilities for scientific and industrial applications.
Overcoming Challenges and Advancing the Field
One of the key challenges in this field has been the availability of high-repetition-rate target systems. The researchers addressed this by using a rotating target wheel, which allowed them to conduct the experiment at a repetition rate of 1 Hz in bursts of 75 shots.
Fig. 3
Additionally, the team carefully characterized the accelerated ions and the generated neutrons, using calibrated Thomson ion spectrometers and time-of-flight neutron detectors. This detailed analysis enabled them to understand the underlying physics and optimize the experimental setup for maximum neutron yield.
Collaboration and Future Research Directions
The success of this study was the result of a collaborative effort involving researchers from various institutions, including the University of Szeged, the Institute for Basic Science in Korea, and the University of Santiago de Compostela in Spain.
Fig. 4
Going forward, the researchers plan to explore ways to further scale up the neutron yield and repetition rate, potentially reaching the goal of a 1010 neutrons per second source. This would involve the development of even more advanced laser systems and target delivery mechanisms, as well as continued refinement of the experimental setup and data analysis techniques.
Overall, this breakthrough in laser-driven neutron generation represents a significant step forward in the field of nuclear physics and its applications, with the potential to unlock new avenues of research and technological advancements across a wide range of disciplines.
Meta description: Researchers have achieved a breakthrough in laser-driven neutron generation, significantly increasing the neutron yield and opening up new possibilities for applications in nuclear physics, medical research, material science, and more.
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