The method of numeral simulating the coincidence neutron detection is proposed with combining the neutron transportation and probabilistic calculation . the method is introduced and used to simulate the nuclear warhead induced fission by source neutrons with energy below 1 mev 推導(dǎo)并提出用中子輸運(yùn)計(jì)算與概率方法結(jié)合計(jì)算符合中子計(jì)數(shù),對(duì)能量低于1mev的外源中子照射核彈頭誘發(fā)裂變的符合中子測(cè)量作了數(shù)值模擬。
In analyzing the neutron active detection , the neutron multiplication in the nuclear warheads induced by outer neutron source with different neutron energys is studied with numeral simulation , and the feasibility of through counting neutrons to determine the presence of high enrichment uranium ( heu ) in nuclear warhead has been proved . the method of detecting the warhead which contains heu pit by counting the released neut rons whose energy is higher than that of source neutron is studied . the feasibility of this method has been studied 對(duì)幾種主動(dòng)探測(cè)核彈頭方法進(jìn)行的研究中,首先對(duì)不同能量各向同性外源中子照射核彈頭的中子增殖行為進(jìn)行了數(shù)值模擬,檢驗(yàn)了用外源中子照射核彈頭后,通過測(cè)量瞬發(fā)中子在核彈頭中的增殖量,來證明核彈頭中高濃鈾存在的可行性;研究了用能量低于1mev的外中子源照射核彈頭,用測(cè)量核彈頭中裂變產(chǎn)生的高于源中子能量中子數(shù)的方法探測(cè)核彈頭,通過數(shù)值模擬分析了可行性。
The measurement data is scarce in 8 - 13 mev region due to the lack of mono - energetic neutron sources ( in this region , there are breakup neutrons besides the mono - energetic neutrons in the often used neutron sources such as t ( p , n ) 3 he and d ( d , n ) 3he sources . the secondary neutrons induced by breakup source neutrons will seriously contaminate the secondary neutron spectra induced by mono - energetic source neutrons ) . therefore , precise measurement for some key nuclides is necessary to check the evaluations in this region 但在8 ? 13mev這一能區(qū),由于沒有合適的單能中子源(因?yàn)樵谶@一能區(qū),對(duì)于常規(guī)中子源如t ( p , n ) ~ 3he和d ( d , n ) ~ 3he中子源,除了單能中子以外,還有破裂中子成份,這部分源破裂中子在樣品上引起的次級(jí)中子,將嚴(yán)重影響測(cè)量結(jié)果) ,所以至今在8 ? 13mev能區(qū)這方面的測(cè)量數(shù)據(jù)極少。