- 作者： 江祥輝; 林有仁; 廖森彥
- 作者服務機構： 國立清華大學核子工程系; 國立清華大學原子科學研究所
- 中文摘要：
利用穿零脈形鑑別法的 NE-213 中子能譜儀測量了 1～21 MeV 快中子能譜，詳細研討穿零脈
形鑑別法的技術，以及影響上升時譜的因素。選擇上升時譜適當的中子鑑別水平，使得 10 MeV
以上高能量中子能被較精確地測量出來。為確證在長時間測量下，上升時譜的穩定，本實驗採用
了一套上升時譜自動監視記錄裝置。
測量所得脈高能譜利用 FORIST 程式，以及伊利諾大學中子響應矩陣加以展開，程式中之
幾個較敏感之參數亦加以敘述。
鈽-鈹和鉲-252 中子源被用來測試所建立 NE-213 中子能譜儀之正確性。測得的鈽-鈹能譜
有 1.3、3.2、4.8、6.7、7.8 和 9.8 MeV 等能?，與已發表的數據很吻合；鉲-252 的分裂中子能
譜在 1.6 和 20 MeV 之間，可用馬克斯威爾分佈擬合，其中子溫度為 1.407 MeV。
以上建立之 NE-213 能譜儀被用來測量清華水池式反應器 E-1 中子束道在 2 瓩運轉時之快
中子能譜，所測得的結果與以往用 Li-6 和 He-3 三明治形半導體能譜儀所測結果相較，高能部
份相當吻合，但大約 4 MeV 以下，後者所得結果大約低了三倍，與 Clifford 等人用相同尺寸之
NE-213 能譜儀對一類似反應器所測之能譜相較，在整個能量範圍都非常吻合。
e - 英文摘要： An Ne-213 spectrometry system using zero-crossing pulse-shape discrimination has been usedto measure fast neutron spectra in the energyrange of 1-21 MeV. Some factors influencingrise-time spectra were discussed in detail. Bychoosing adequate discrimination level of arise-time spectrum, the high energy neutronsabove 10 MeV have been measured more accura-tely. The rise-time spectrum has been monitoredduring the long-time measurement so as to verifythe stability of the spectrometry system. The FORIST code in coupled with theIllinois neutron response matrix was used tounfold the measured pulse-height spectra. Somesensitive parameters in FORIST code were men-tioned. The energy spectra of Pu-Be and C -neutron sources were measured to test the re-liability of the spectrometry system. The Pu-Bufast-neutron spectrum was found to have peaksat 1.3, 3.2, 4.8, 6.7, 7.8, and 9.8 MeV whichagrees very well with the published data. The C -fast-neutron spectrum was found to beadequately described by a single Maxwelliandistribution fitted between 1.6 and 20 MeV witha temperature of 1.407 MeV. Finally, the established NE-213 spectro-metry system was used to measure the fast-neutron spectrum at E-1 beam port in THOR.The measured spectrum has been comparedwith those of former measurements using Li-and He-sandwich-type semiconductor spectro-meters. The spectra agree very well at highenergies. Below about 4 MeV, however, thelatters are lower by an order of about three.Compared with the result of clifford et al. usingNE-213 of the same size at a similar reactor,the agreement is very well in the whole energyrange.
- 中文關鍵字： --
- 英文關鍵字： --
