11 research outputs found
A large area, high counting rate micromegas-based neutron detector for BNCT
Beam monitoring and evaluation are very important to boron neutron capture
therapy (BNCT), and a variety of detectors have been developed for these
applications. However, most of the detectors used in BNCT only have a small
detection area, leading to the inconvenience of the full-scale 2-D measurement
of the beam. Based on micromegas technology, we designed a neutron detector
with large detection area and high counting rate. This detector has a detection
area of 288 mm multiples 288 mm and can measure thermal, epithermal, and fast
neutrons with different detector settings. The BNCT experiments demonstrated
that this detector has a very good 2-D imaging performance for the thermal,
epithermal, fast neutron and gamma components, a highest counting rate of 94
kHz/channel, and a good linearity response to the beam power. Additionally, the
flux fraction of each component can be calculated based on the measurement
results. The Am-Be neutron source experiment indicates that this detector has a
spatial resolution of approximately 1.4 mm, meeting the requirements of
applications in BNCT. It is evident that this micromegas-based neutron detector
with a large area and high counting rate capability has great development
prospects in BNCT beam monitoring and evaluation applications
Precision Higgs physics at the CEPC
The discovery of the Higgs boson with its mass around 125 GeV by the ATLAS
and CMS Collaborations marked the beginning of a new era in high energy
physics. The Higgs boson will be the subject of extensive studies of the
ongoing LHC program. At the same time, lepton collider based Higgs factories
have been proposed as a possible next step beyond the LHC, with its main goal
to precisely measure the properties of the Higgs boson and probe potential new
physics associated with the Higgs boson. The Circular Electron Positron
Collider~(CEPC) is one of such proposed Higgs factories. The CEPC is an
circular collider proposed by and to be hosted in China. Located in a
tunnel of approximately 100~km in circumference, it will operate at a
center-of-mass energy of 240~GeV as the Higgs factory. In this paper, we
present the first estimates on the precision of the Higgs boson property
measurements achievable at the CEPC and discuss implications of these
measurements.Comment: 46 pages, 37 figure
Two-Dimensional SnSe Films on Paper Substrates for Flexible Broadband Photodetectors
Paper-based devices have aroused researchers’
enormous interest
due to the increasing need for disposable flexible optoelectronic
devices. Here, we used a straightforward painting method to integrate
semiconducting materials on an A4 paper substrate to create high-performance
photodetectors. A solvent-free 2D SnSe film painted on paper allowed
electrons to separate from holes more effectively, thereby reducing
the level of recombination between holes and electrons. The paper-based
SnSe photodetectors that we prepared demonstrated a robust, sensitive
response over a wide range of spectral ranges from ultraviolet (254
nm) to near-infrared (1550 nm). The devices were characterized by
fast response times (rise time of 0.066 s and fall time of 0.066 s).
A high-performance photodetector was achieved by combining a photoconductive
and pyroelectric effect. Additionally, we constructed the carbon nanotube
(CNTs) films as electrodes in order to form an ohmic contact between
the carbon nanotubes and the semiconductor, and the photogenerated
electrons were able to efficiently move through the carbon nanotubes.
Our research could contribute to the development of flexible photodetection
devices that are low-cost, eco-friendly, and disposable
3D Printing of Nacre-Inspired Structures with Exceptional Mechanical and Flame-Retardant Properties
Flame-retardant and thermal management structures have attracted great attention due to the requirement of high-temperature exposure in industrial, aerospace, and thermal power fields, but the development of protective fire-retardant structures with complex shapes to fit arbitrary surfaces is still challenging. Herein, we reported a rotation-blade casting-assisted 3D printing process to fabricate nacre-inspired structures with exceptional mechanical and flame-retardant properties, and the related fundamental mechanisms are studied. 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) modified boron nitride nanoplatelets (BNs) were aligned by rotation-blade casting during the 3D printing process to build the “brick and mortar” architecture. The 3D printed structures are more lightweight, while having higher fracture toughness than the natural nacre, which is attributed to the crack deflection, aligned BN (a-BNs) bridging, and pull-outs reinforced structures by the covalent bonding between TMSPMA grafted a-BNs and polymer matrix. Thermal conductivity is enhanced by 25.5 times compared with pure polymer and 5.8 times of anisotropy due to the interconnection of a-BNs. 3D printed heat-exchange structures with vertically aligned BNs in complex shapes were demonstrated for efficient thermal control of high-power light-emitting diodes. 3D printed helmet and armor with a-BNs show exceptional mechanical and fire-retardant properties, demonstrating integrated mechanical and thermal protection
CEPC Conceptual Design Report: Volume 2 - Physics & Detector
The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios
CEPC Conceptual Design Report: Volume 2 - Physics & Detector
The Circular Electron Positron Collider (CEPC) is a large international scientific facility proposed by the Chinese particle physics community to explore the Higgs boson and provide critical tests of the underlying fundamental physics principles of the Standard Model that might reveal new physics. The CEPC, to be hosted in China in a circular underground tunnel of approximately 100 km in circumference, is designed to operate as a Higgs factory producing electron-positron collisions with a center-of-mass energy of 240 GeV. The collider will also operate at around 91.2 GeV, as a Z factory, and at the WW production threshold (around 160 GeV). The CEPC will produce close to one trillion Z bosons, 100 million W bosons and over one million Higgs bosons. The vast amount of bottom quarks, charm quarks and tau-leptons produced in the decays of the Z bosons also makes the CEPC an effective B-factory and tau-charm factory. The CEPC will have two interaction points where two large detectors will be located. This document is the second volume of the CEPC Conceptual Design Report (CDR). It presents the physics case for the CEPC, describes conceptual designs of possible detectors and their technological options, highlights the expected detector and physics performance, and discusses future plans for detector R&D and physics investigations. The final CEPC detectors will be proposed and built by international collaborations but they are likely to be composed of the detector technologies included in the conceptual designs described in this document. A separate volume, Volume I, recently released, describes the design of the CEPC accelerator complex, its associated civil engineering, and strategic alternative scenarios