Hexbyte Glen Cove Scientists invent lead-free composite shielding material for neutrons and gamma-rays

Hexbyte Glen Cove

Schematic diagram of shielding mechanism of modified nano composite shielding material. Credit: Huo Zhiping

Dr. Huo Zhipeng and his student Zhao Sheng from the Hefei Institutes of physical science (HFIPS) of the Chinese Academy of Sciences recently developed a lead-free neutron and gamma ray composite shielding material that has high shielding properties and is environmentally friendly. Their results were published in Nuclear Materials and Energy.

The composite, modified-gadolinium oxide// (Gd2O3/B4C/HDPE), was tested safe and effective to shield neutron and gamma rays through a series of intricate and comprehensive experiments.

Neutron, as an electrically neutral particle, has a strong penetrability and always emits secondary during particle collision process. The scientific and efficient scheme of shielding neutron is to select high Z (atomic number), low Z materials, and neutron absorbing materials simultaneously for combined shielding. However, lead-containing materials are restricted in application with biological toxicity.

Rare earth element gadolinium, usually exists in the form of non-toxic Gd2O3 in nature, has always shown high average thermal neutron absorption, high temperature resistance and good gamma shielding performance.   

The researchers studied the shielding mechanism first, and then adopted the coupling agents to modify the surface of Gd2O3 to improve the interfacial compatibility and dispersion of Gd2O3 in the matrix.

“It is lead-free and poses no threat to the environment or humans,” said Dr. Huo, who has been engaged in radiation and environmental protection for years. 

He further explained how this radiation shielding system worked. Fast neutrons collide with gadolinium (Gd) inelastically, and collide elastically with hydrogen until they become thermal neutrons, finally, absorbed by high Z element Gd and boron.

The show that the neutron shielding rate of the composite can reach 98% under the condition of 15 cm thickness in CF-252 environment. In cS-137 and CO-60 environments, the gamma shielding rates of the composite are 72% and 60%, respectively, at the same thickness.   

Its comprehensive shielding performance is better than conventional boron-polyethylene collimating shielding, and it is suitable for neutron spectrum and gamma spectrum diagnosis system of Experimental Advanced Superconducting Tokamak (EAST). It is expected to be a promising radiation shielding material for neutron-gamma mixed fields, according to the researchers.



More information:
Zhipeng Huo et al, Surface modified-gadolinium/boron/polyethylene composite with high shielding performance for neutron and gamma-ray, Nuclear Materials and Energy (2021). DOI: 10.1016/j.nme.2021.101095

Citation:
Scientists invent lead-free composite shielding material for neutrons and gamma-rays (2021, December 23)
retrieved 26 December 2021
from https://phys.org/news/2021-12-scientists-lead-free-composite-shielding-material.html

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Hexbyte Glen Cove Physicists invent printable superconducting device thumbnail

Hexbyte Glen Cove Physicists invent printable superconducting device

Hexbyte Glen Cove

Credit: Leiden Institute of Physics

Superconducting devices such as SQUIDS (Superconducting Quantum Interferometry Device) can perform ultra-sensitive measurements of magnetic fields. Leiden physicsts invented a method to 3-D-print these and other superconducting devices in minutes.

“Fabricating on a computer chip is a multi-step and demanding procedure, requiring dedicated facilities,” says Kaveh Lahabi, a physicist at Leiden Universty. “It usually takes days to complete,”

Lahabi and co-authors have developed a new approach, in which Josephson junctions, essential parts of SQUIDS, can be printed on almost any surface in mere minutes, within an electron microscope.

In this video, Lahabi and co-author Tycho Blom demonstrate their technique and discuss their recent article in ACS Nano.

Kaveh Lahabi explaining the 3D-printing process, and walking us through the lab steps Credit: Kaveh Lahabi


More information:
Tycho J. Blom et al. Direct-Write Printing of Josephson Junctions in a Scanning Electron Microscope, ACS Nano (2020). DOI: 10.1021/acsnano.0c03656

Citation:
Physicists invent printable superconducting device (2020, November 27)
retrieved 29 November 2020
from https://phys.org/news/2020-11-physicists-printable-superconducting-device.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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