分类： 物理学 >> 核物理学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： The key to large-scale parallel solutions of deterministic particle transport problem is single-node computation performance. Hence, single-node computation is often parallelized on multi-core or many-core computer architectures. However, the number of on-chip cores grows quickly with the scale-down of feature size in semiconductor technology. In this paper, we present a scalability investigation of one energy group time-independent deterministic discrete ordinates neutron transport in 3D Cartesian geometry (Sweep3D) on Intels Many Integrated Core (MIC) architecture, which can provide up to 62 cores with four hardware threads per core now and will own up to 72 in the future. The parallel programming model, OpenMP, and vector intrinsic functions are used to exploit thread parallelism and vector parallelism for the discrete ordinates method, respectively. The results on a 57-core MIC coprocessor show that the implementation of Sweep3D on MIC has good scalability in performance. In addition, the application of the Roofline model to assess the implementation and performance comparison between MIC and Tesla K20C Graphics Processing Unit (GPU) are also reported.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
ZHANG Zhan-Gang
LIU Jie
HOU Ming-Dong
SUN You-Mei
SU Hong
GU Song
GENG Chao
YAO Hui-Jun
LUO Jie
DUAN Jing-Lai
MO Dan
XI Kai
EN Yun-Fei
摘要： Experimental evidence is presented showing obvious azimuthal dependence of single event upsets (SEU) and multiple-bit upset (MBU) patterns in radiation hardened by design (RHBD) and MBU-sensitive static random access memories (SRAMs), due to the anisotropic device layouts. Depending on the test devices, a discrepancy from 24.5% to 50% in the SEU cross sections of dual interlock cell (DICE) SRAMs is shown between two perpendicular ion azimuths under the same tilt angle. Significant angular dependence of the SEU data in this kind of design is also observed, which does not fit the inverse-cosine law in the effective LET method. Ion trajectory-oriented MBU patterns are identified, which is also affected by the topological distribution of sensitive volumes. Due to that the sensitive volumes are periodically isolated by the BL/BLB contacts along the Y-axis direction, double-bit upsets along the X-axis become the predominant configuration under normal incidence. Predominant triple-bit upset and quadruple-bit upset patterns are the same under different ion azimuths (L-shaped and square-shaped configurations, respectively). Those results suggest that traditional RPP/IRPP model should be promoted to consider the azimuthal and angular dependence of single event effects in certain designs. During earth-based evaluation of SEE sensitivity, worst case beam direction, i.e., the worst case response, should be revealed to avoid underestimation of the on-orbit error rate.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
WANG Xiao-Hui
TONG Teng
SU Hong
LIU Jie
ZHANG Zhan-Gang
GU Song
LIU Tian-Qi
KONG Jie
ZHAO Xing-Wen
YANG Zhen-Lei
摘要： Single event effects (SEEs) induced by radiations become a significant reliability challenge for modern electronic systems. To evaluate SEEs susceptibility for microelectronic devices and integrated circuits (ICs), an SEE testing system with flexibility and robustness was developed at Heavy Ion Research Facility in Lanzhou (HIRFL). The system is compatible with various types of microelectronic devices and ICs, and supports plenty of complex and high-speed test schemes and plans for the irradiated devices under test (DUTs). Thanks to the combination of meticulous circuit design and the hardened logic design, the system has additional performances to avoid an overheated situation and irradiations by stray radiations. The system has been tested and verified by experiments for irradiating devices at HIRFL.
分类： 核科学技术 >> 核材料与工艺技术 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
SHANG Jian-Bo
SHI Quan-Lin
WANG Qun-Shu
ZHONG Zhen-Yuan
LEI Bei-Fang
LIU Jie
BAI Tao
DAI Yi-Hua
LI Mou
摘要： In this paper, a new model is proposed to calculate distribution of fission products in particles of different sizes. The model sensitivity to the effective volume and mass of vaporized soil particles is examined. Compared with other fractionation models, the new method has a much better performance in calculating r89,95, but the calculated cumulative activity fraction for particles in diameters over 100 m is in between the results using the F-T and G-X models. It is concluded that in a near surface nuclear explosion radioactivity is mainly distributed in soil particles which have not been vaporized, and according to the Henrys law and ideal gas law, r89,95 may vary in larger particles when effective volume of the fireball is changed.
分类： 核科学技术 >> 核探测技术与核电子学 提交时间： 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要： Single event upsets (SEUs) induced by heavy ions were observed in 65 nm SRAMs to quantitatively evaluate the applicability and effectiveness of single-bit error correcting code (ECC) utilizing Hamming Code. The results show that the ECC did improve the performance dramatically, with the SEU cross sections of SRAMs with ECC being at the order of 10-11 cm2/bit, two orders of magnitude higher than that without ECC (at the order of 10-9 cm2/bit). Also, ineffectiveness of ECC module, including 1-, 2- and 3-bits errors in single word (not Multiple Bit Upsets), was detected. The ECC modules in SRAMs utilizing (12, 8) Hamming code would lose work when 2-bits upset accumulates in one codeword. Finally, the probabilities of failure modes involving 1-, 2- and 3-bits errors, were calcaulated at 39.39%, 37.88% and 22.73%, respectively, which agree well with the experimental results.
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