中子活化■(R)矩阵元的新表达方式

A NEW EXPRESSION FOR NEUTRON ACTIVATION (?) (R)-MATRIX ELEMENTS

继文献[1]后,又提出了一种中子活化R矩阵元的新表达方式.以175Yb（i或j）-160Yb（j或i）,153Gd（i或j）-159Gd（j或i）,103Ru（i或j）-97Ru（j或i）或95Zr（i或j）-97Zr（j或i）为中子能谱监测器,j为标准Rij为中子能谱指针.定义相对偏离热化系数x=(Rij-1)/(Q0i-Q0j)《1,Q0i和Q（0j）分别为i和j的母核的无限稀释共振积分截面与热中子俘获截面之比值,则Rij=1+aijx,RRj=1+（?）akmxm,k代表i和j以外诸核素,Rkj级数迅速收敛.Rkj的准确度不受Q0i用Q0j的误差的影响.用高精度实验测定诸akm值,可同时用4种中子能谱监测器（兼作标准）,以Rij定x。

This paper gives a new expression for neutron activation R-matrix dements.Use ^(175)Yb (i or j)-^(169)Yb(j or i),^(153)Cd(i or j)-^(159)Cd(j or i),^(103)Ru (i or j)-^(97)Ru(j or i),or ^(95)Zr(i or j)-^(97)Zr(j or i) as neutron energy spectra monitor,j as standard,and R_(ij) as neutron spectra indicator.Define relative deviation from thermalization:x=(R_(ij)-1)/(Q_(0i)-Q_(0j))《1,where Q_(0i) and Q_(0j) are the ratios of resonance integral and thermal neutron capture cross sec- tion of the parents of i and j respectively.Then,R_(ij)=1+a_1~ix,R_(kj)=1+(?) a_m^kx^m,where k represents nuclides other than i and j.R_(kj) series converge rapidly for all k.The accuracy of R_(kj) will not be affected by the errors of Q_(0i) and Q_(0j).The a_m^(k′)s may be determined by experiments of high precision. The author may use simultaneously four kinds of neutron energy spectra monitor (also used as standards),use R_(ij) to determine x,and use x and a_m^(k′)s to calculate R_(kj),R_(kj),and B_k^0.Then,very reliable results may be obtained. This is the mono-standard or small-number-standards method in the neutron activation analysis.