The neutron total cross section of iron ( natFe) plays an important role in the basic science of nuclear physics, nuclear technology and nuclear energy application. A new measurement of the total cross section of iron from 0.3 eV to 150 MeV was carried out in single and double bunch modes by transmission method and time of flight method with multi-cell fast fission ionization chamber (FIC) with 235U and 238U coating materials at the China Spallation Neutron Source (CSNS). Normalized fission counts-neutron energy spectra for sample-in and sample-out states were obtained and superimposed. The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV. The transmissions obtained in single bunch and unfolded in double bunch coincided well. From 0.3 eV to 150 MeV, the ratio of most energy points of cross section in single bunch and in double bunch fluctuates within 10 %. In the energy range of 0.3 eV to 10 keV, the experimental results using 20 mm and 40 mm thickness iron samples both agree very well with the evaluated data of JEFF-3.3 and ENDF/B-VIII.0 at most energy points, fluctuating within 3 %. In the energy range of 10 keV to 150 MeV, the results agree well with the evaluated data in terms of values and trends. The main resonance peaks of the total cross section of iron at the energies of 3.94 keV, 6.24 keV, 7.76 keV, 27.9 keV, 52.1 keV, 74.1 keV, 83.9 keV, 141 keV, 170 keV, 188 keV and 386 keV are well represented in our results. The relative uncertainties of the total cross sections using the 40 mm iron sample by FIC- 235U are within 2 % at most energy points. In 1.5 MeV-140 MeV region, the relative uncertainties of the total cross section using the 20 mm iron and 40 mm iron samples by FIC- 238U are around 2 % and 1 %, respectively. The total cross section results can be used as a reference for nuclear data evaluation.

China

Jiangbo Bai

Jingyu Tang

Liqun Shi

Yonghao Chen

Han Yi

Guohui Zhang

Haofan Bai

Jie Bao

Ping Cao

Zhen Chen

Zengqi Cui

Anchuan Fan

Ruirui Fan

Changqing Feng

Fanzhen Feng

Keqing Gao

MinHao Gu

Changcai Han

Guozhu He

Yongcheng He

Yang Hong

Yiwei Hu

Hanxiong Huang

Weihua Jia

Haoyu Jiang

Wei Jiang

Zhijie Jiang

Zhengyao Jin

Ling Kang

Bo Li

Chao Li

Gong Li

Jiawen Li

Qiang Li

Xiao Li

Yang Li

Jie Liu

Shubin Liu

Guangyuan Luan

Changjun Ning

Binbin Qi

Jie Ren

Xichao Ruan

Zhaohui Song

Kang Sun

Zhixin Tan

Shengda Tang

Lijiao Wang

Pengcheng Wang

Zhaohui Wang

Xiaoguang Wu

Xuan Wu

Likun Xie

Yongji Yu

Linhao Zhang

Mohan Zhang

Qiwei Zhang

Xianpeng Zhang

Yuliang Zhang

Yue Zhang

Zhiyong Zhang

Maoyuan Zhao

Luping Zhou

Zhihao Zhou

Kejun Zhu

Measurement of the neutron total cross section of Iron at the Back-n white neutron source of CSNS

Scattering amplitudes in planar <math> <mi>N</mi> </math> $$ \mathcal{N} $$ = 4 super Yang-Mills theory exhibit singularities which reflect various aspects of the cluster algebras associated to the Grassmannians Gr(4, n) and their tropical counterparts. Here we investigate the potential origins of such structures and examine the extent to which they can be recovered from the Gröbner structure of the underlying Plücker ideals, focussing on the Grassmannians corresponding to finite cluster algebras.

Mexico

L. Bossinger

United Kingdom

J. Drummond

R. Glew

Adjacency for scattering amplitudes from the Gröbner fan

$^{232}$Th/$^{233}$U fuel cycle is an alternate candidate for future nuclear energy. Neutron-induced fission cross section of $^{232}$Th is one of the important nuclear data if using thorium as the fuel in the future. $^{232}$Th(n, f) cross sections from 1 to 300 MeV were measured at China Spallation Neutron Source (CSNS) Back-streaming neutron facility (Back-n) relative to $^{235}$U(n, f) and n-p scattering. A fast ionization chamber for fission cross section measurement (FIXM) and a proton recoil telescope (PRT) were used to perform the measurement. The neutron energy in this measurement reaches up to 300 MeV which is supposed to be the highest among the current Experimental Nuclear Reaction Data (EXFOR) library. It stands as the only experimental data in the region of 200-300 MeV in EXFOR as well. The experimental and evaluated data of $^{232}$Th(n, f) cross section above 60 MeV are scarce, the measurement data of this work will be valuable references for future evaluation in high energy. For the data below 60 MeV, most of our data are more consistent with ENDF/B-VIII.0, excepting in the region of 1-2 MeV where our data are more in favor of CENDL-3.2.

Yiwei Yang

Zhizhou Ren

Rong Liu

Hantao Jing

Qi An

Yu Bao

Haolei Chen

Qiping Chen

Xiaolong Gao

Minhao Gu

Zijie Han

Xiru Huang

Xingyan Liu

Ze Long

Mengchen Niu

Zhijia Sun

Xinyi Tang

Binbin Tian

Zhongwei Wen

Xiaoyun Yang

Li Yu

Tao Yu

Measurement of neutron-induced fission cross sections of Th from 1 to 300 MeV at CSNS Back-n

Within QCD reggeon field theory we study the formation of two subsequent triple pomeron vertices in the process P→PP→PPP. We make use of an earlier investigation [1] of the six-reggeon amplitude in deep inelastic scattering and show that in the large-N  c  limit pomeron fan diagrams emerge with the same triple pomeron vertex in all places. We thus confirm the BK-equation, but we also find additional terms related to the reggeization of the gluon, and we discuss their potential significance. Our analysis also includes the general pomeron → two odderon vertex: a particular version of this vertex has been included into earlier generalizations the BK equation.