201040570 六、發明說明: 【發明所屬之技術領域】 一種使用精準時序計測技術,集合環境加馬輻射等效 劑量率與能譜核種分析同步報知功能於一身之連續監測儀 器之設計方法與實施裝置。 【先前技術】 至目前為止,應用於極低強度之環境輻射測量(0.01 // 〇 Sv/h〜100 /2 Sv/h),政府輕射防護管制單位對游離輻射作業 場所周圍之環境加馬輻射連續監測與記錄,大多使用高壓 游離腔、蓋革管或半導體矽二極體,作為偵檢器,在施以 適當之電壓下,以電流大小或脈衝計數率來測量環境加馬 輻射強.度。其優點為裝置輕巧、精準度高而且具備全向性 測量能力,適合廣區域多點布置。缺點為受限於材質低原 子序及密度特性,無法吸收一般人造核種加馬射線全部能 量,僅有劑量率測量功能,不能即時報知環境輻射核種分 〇 布變化情報。因此,遇到核子事故導致劑量率異常昇高時, 現有之作業方式均須派遣人員或環境偵測車冒險進入現場 偵測數據、採集空氣、土壤、或排水等樣品送回實驗室分 析,無法即時掌握環境輻射核種分布變化狀況。 " 若欲建立即時報知環境輻射核種分布變化情報能力, 依照原子能委員會公布之『環境輻射偵測規範』,則必須 使用可作加馬射線全部能量吸收、高原子序及密度之閃爍 計數器偵檢頭(例如:直徑2〜3吋厚度2〜3吋之圓柱體碘化 4 201040570 納配上光電倍增管),另外建立獨立之偵測站。其工作原 理乃乂偵k器接叉放射線撞擊,收集其能量吸收產生之 游離電荷後,轉為高度與能量相關之脈衝,再將脈衝以主 動慮波je_ i為近似咼斯分佈shape)之外 型後’抓取其峰值維持於一低漏電率之電容上,或直接以 向速類比/數位轉換态加以鏗別(Successive Approximation ADC) ’或採用定電流釋放電荷再對釋放時間作精準計時 (Wilkinson ADC)測量脈衝峰值,最後統計輻射脈衝高度分 〇 佈情形,進而判讀放射性同位素核種。電路設計方面,大 多需要經精確校調之低雜訊前置放大器、整型放大器、高 速類比/數位轉換器等高精密等級標準電子裝備模組,如 NIM(Nuclear Instrumentation Module)或 CAMAC (Computer201040570 VI. Description of the invention: [Technical field to which the invention pertains] A design method and implementation apparatus for a continuous monitoring instrument using a precise time-series measurement technique, a combined environment, a radiation dose equivalent dose rate, and an energy spectrum nuclear analysis synchronization notification function. [Prior Art] Up to now, it has been applied to extremely low-intensity environmental radiation measurement (0.01 // 〇Sv/h~100 /2 Sv/h), and the government light-light protection control unit has added to the environment around the free-radiation workplace. Continuous monitoring and recording of radiation, mostly using high-pressure free cavity, Geiger tube or semiconductor 矽 diode, as a detector, under the appropriate voltage, the current magnitude or pulse count rate to measure the environmental gamma radiation. degree. Its advantages are light weight, high precision and omnidirectional measurement capability, suitable for wide-area multi-point layout. The disadvantage is that it is limited by the low atomic order and density characteristics of the material, and can not absorb the total energy of the common artificial nuclear species plus the horse ray. Only the dose rate measurement function can not immediately inform the environmental radiation nuclear seed 变化 cloth change information. Therefore, in the event of a nuclear accident causing an abnormally high dose rate, existing methods of operation must dispatch personnel or environmental detection vehicles to venture into the field to detect data, collect air, soil, or drainage samples and send them back to the laboratory for analysis. Instantly grasp the changes in the distribution of environmental radiation nuclear species. " If you want to establish an immediate notification of the environmental radiation nuclear distribution change intelligence capabilities, in accordance with the "Environmental Radiation Detection Specification" published by the Atomic Energy Commission, you must use a scintillation counter that can be used for all energy absorption, high atomic order and density of the Jiama ray. Head (for example: 2~3吋 diameter 2~3吋 cylinder iodine 4 201040570 nano with photomultiplier tube), and establish an independent detection station. The working principle is that the detector detects the interference of the radiation, collects the free charge generated by the energy absorption, and then converts it into a pulse of height and energy, and then takes the pulse with the active wave je_ i as the approximate shape of the Muse. After the type, 'grab the peak at a low leakage rate capacitor, or directly in the speed analog/digital conversion state (Successive Approximation ADC)' or use a constant current to discharge the charge and then accurately time the release time ( Wilkinson ADC) measures the peak value of the pulse, and finally counts the height of the radiation pulse, and then reads the radioactive isotope. In terms of circuit design, many high-precision standard electronic equipment modules such as NIM (Nuclear Instrumentation Module) or CAMAC (Computer), such as low noise preamplifiers, integer amplifiers, and high-speed analog/digital converters, which are precisely calibrated, are required.
Automatic Measurement and Control)規格產品搭配工作站 電腦軟體程式工作。不但成本驚人,其耐候性與持續工作 能力差、工作條件要求嚴酷、系統笨重、組裝與維護麻煩 等特性,使其戶外環境偵測應用時,必須安放於具備良好 〇 空調之建築物内,對偵測對象以空氣或水取樣送入偵測站 内固定之裝備使用,因此無法廣區域多點布置。若人口稠 後、地區遭逢突發核子事故,欲實施大規模人員疏散或發放 ' 蛾片等應變決策,必須增加環境輻射監視布點與即時快速 - 精確掌控環境輻射核種分布變化資訊之早期警報需求,上 述環境加馬輻射連續監測及事後人工取樣方式已完全無法 應付。 為彌補以上缺失,市場上亦有一些用最少能譜解析度 以簡化電子設計、以輕巧為訴求之兼具環境輻射能譜與空 201040570 氣克馬劑量率偵測產品推出’例如加拿大Expl〇rani靡公 司之GR-150早期警報系統或美國〇乂加廿公司之 NanoSpec等等。由於仍然採用傳統類比/數位轉換器專用設 計方式處理脈衝信號,電路特殊性與複雜度無法根本改 善。雖然已無專有建築物遮蔽之需要,這些產品單價仍然 遠超過以蓋革管或矽二極體作為偵檢器之環境輻射監測 儀,阻礙大規模布點之實現可能性。 μ 【發明内容】 本發明所提出之設計方法,主要是應用近代量產低成 本、低耗電之微電腦控制器與高速數位積體電路技術,_將 先前技術之類比數位轉換式輻射脈衝信號能譜分析方法] -改為以全數位高頻時鐘計數之連續計時電路陣列處理。本 發明之設計重點如附圖1所示,對於做為量測對象之環产 .輻射放射線使用一只或多只標準量產之2” χ2”或更二兄 寸峨化納閃燦計數器⑽⑼)作為债檢元件,依場所^ 方式排列,以確保有效測量區域完全涵蓋放射性釋出二 範圍。閃爍計數器以高壓供應器提供工作電壓後,因吸立 ~ 放射線粒子能量而產生高度為Vp之類比脈衝信號,先^訊 定低限為Vth之脈高鑑別電路轉換為含有輻射粒子能量= .· 收與閃爍發光事件特性寬度為W之邏輯脈衝。隨後The Automatic Measurement and Control) product works with a workstation software program. Not only the cost is amazing, its weather resistance and continuous work ability are poor, the working conditions are harsh, the system is cumbersome, and the assembly and maintenance troubles make it suitable for outdoor environment detection applications. It must be placed in a building with good air conditioning. The object to be detected is sampled by air or water and sent to the fixed equipment in the detection station, so it is not possible to arrange multiple points in a wide area. If the population is thick and the area is experiencing a sudden nuclear accident, and you want to implement large-scale evacuation or issue a 'moth-strain response, you must increase the environmental warning monitoring and immediate and rapid-accurate control of the early warning requirements of environmental radiation nuclear distribution changes. The above-mentioned environmental Jiama radiation continuous monitoring and post-sampling manual sampling methods have been completely unable to cope. In order to make up for the above shortcomings, there are also some products in the market that use the minimum energy spectrum resolution to simplify electronic design, and the lightness of the demand for both environmental radiant energy spectrum and the air 201040570 gas gram mass rate detection products launched, for example, Expl〇rani靡 of Canada The company's GR-150 early warning system or NanoSpec from the United States and Canada. Since the pulse signal is still processed by the conventional analog/digital converter design, the circuit specificity and complexity cannot be fundamentally improved. Although there is no need for proprietary building shelter, the unit price of these products far exceeds the environmental radiation monitors that use Geiger tubes or tantalum diodes as detectors, hindering the possibility of large-scale deployment. μ [Summary of the Invention] The design method proposed by the present invention mainly uses a microcomputer controller and a high-speed digital integrated circuit technology for mass production of low-cost, low-power consumption in recent years, and the analog digital conversion radiation pulse signal of the prior art can be used. Spectral analysis method] - Change to continuous timing circuit array processing with full digital high frequency clock counting. The design focus of the present invention is as shown in Fig. 1. For the ring-shaped radiation radiation used as the measurement object, one or more standard production quantities of 2" χ 2" or two brothers are used. (10) (9) As a component of the debt inspection, they are arranged according to the location of the site to ensure that the effective measurement area completely covers the scope of radioactivity release. After the flashing counter supplies the working voltage with the high voltage supply, the pulse signal with a height of Vp is generated by the energy of the absorbing and radiant particles, and the pulse height of the Vth pulse is determined to be converted into the radiant particle energy = . A logic pulse with a characteristic width W of the flickering event event is received. Subsequently
輯脈衝送到同步脈衝時序記錄器電路,以精準時鐘脈衝S 用缓衝半週期(Bu f f ered Semi -Per i od)連續記錄法做時序 記錄。 τ 在使用相同之偵檢器/電路陣列下,以時序記錄資料掏 6 201040570 . 取與演算分析處理裝置(108)透過多只偵檢頭同時計時與 連續記錄之解讀,可以得到多只偵檢頭輻射脈衝時間符合 性(Coincidence)、間距、與寬度之資訊。透過簡單之資料 -處理與演算步驟,就可獲得造成環境輻射核種比例與劑量 . 率偵測結果。 在一實施例中,本發明提供一種全功能環境輻射偵測 裝置,其係即時測量分析環境加馬輻射與輻射作業場所排 放内含加馬放射性物質,該裝置包括:一輻射偵檢元件, 0 其係用於吸收放射粒子產生電子脈衝信號;一電路元件, 其係用於偵檢元件工作電壓供應與脈衝信號整理;一時序 記錄元件,其係用於脈衝信號發生與寬窄計測;以及一顯 示控制元件,其係用於放射性分析與偵檢程序。 【實施方式】 為使貴審查委員能對本發明之特徵、目的及功能有 更進一步的認知與瞭解,下文特將本發明之裝置的相關細 ❹ 部結構以及設計的理念原由進行說明,以使得審查委員可 以了解本發明之特點,詳細說明陳述如下: 本發明所提出之設計方法,主要是應用近代量產低成 本、低耗電之微電腦控制器與南速數位積體電路技術’將 〜 先前技術之類比數位轉換式輻射脈衝信號能譜分析方法, 改為以全數位高頻時鐘計數之連續計時電路陣列處理。本 發明之設計重點如圖1所示,對於做為量測對象之環境輻 射放射線使用一只或多只標準量產之2”x2”或更大尺寸碘 化鈉閃爍計數器(Nal(Tl))作為偵檢元件,依場所需要方式 7 201040570 • 排列(101),以確保有效測量區域完全涵蓋放射性釋出方位 範圍。閃螺计數器以南壓供應器(102)提供工作電壓後,因 吸收放射線粒子能量而產生高度為Vp之類比脈衝信號 (103) ’先經§又疋低限為Vth之脈馬鐘別電路(1 )轉換為 含有輕射粒子能I吸收與閃爍發光事件特性寬度為W之邏 輯脈衝(105)。隨後再將邏輯脈衝送到同步脈衝時序記錄器 電路(106) ’以精準時鐘脈衝(1 〇7)採用緩衝半週期(BufferS Semi-Period)連續記錄法做時序記錄。 〇 在使用相同之偵檢态/電路陣列下,以時序記錄資料擷The pulse is sent to the synchronous pulse timing recorder circuit, and the timing recording is performed by the buffer clock half-cycle (Bu f ered Semi - Per od) continuous recording method with the accurate clock pulse S. τ Under the same detector/circuit array, the data is recorded in time series 掏6 201040570. The calculus analysis processing device (108) can obtain multiple detections through simultaneous interpretation of multiple detection heads and continuous recording. Head radiation pulse time compliance (Coincidence), spacing, and width information. Through simple data-processing and calculation steps, the ratio of environmental radiation to nuclear radiation and the rate of detection can be obtained. In one embodiment, the present invention provides a full-featured environmental radiation detecting device for instantaneously measuring and analyzing an environment, a radiation-radiating and a radiation-emitting work site, including a radioactive substance, including: a radiation detecting component, 0 It is used to absorb radiation particles to generate electronic pulse signals; a circuit component for detecting component operating voltage supply and pulse signal alignment; a time recording component for pulse signal generation and width measurement; and a display Control element, which is used for radiological analysis and detection procedures. [Embodiment] In order to enable the reviewing committee to have a further understanding and understanding of the features, objects and functions of the present invention, the following is a detailed description of the related details of the device and the design concept of the device of the present invention. The members can understand the characteristics of the present invention, and the detailed description is as follows: The design method proposed by the present invention mainly applies the low-cost, low-power microcomputer controller and the south-speed digital integrated circuit technology in the modern production. The analog-digital conversion type radiation pulse signal energy spectrum analysis method is changed to a continuous timing circuit array with full digital high-frequency clock counting. The design focus of the present invention is shown in Figure 1. One or more standard quantities of 2"x2" or larger sodium iodide scintillation counters (Nal(Tl)) are used for the ambient radiation radiation used as the measurement object. As a detection component, depending on the location required 7 201040570 • Arrange (101) to ensure that the effective measurement area fully covers the radioactive release range. After the flash voltage counter supplies the working voltage with the south voltage supply (102), it generates an analog pulse signal with a height of Vp due to the absorption of the radiation particle energy. (103) 'The pulse is first § and the lower limit is Vth. The circuit (1) is converted to a logic pulse (105) having a characteristic width W of the absorption and scintillation event of the light-emitting particles. The logic pulse is then sent to the sync pulse timing recorder circuit (106) to perform timing recording with a precision clock pulse (1 〇 7) using a BufferS Semi-Period continuous recording method.记录 Record data in time series using the same detection state/circuit array撷
取與演异分析處理裝置(108)透過多只偵撿頭同時計時與 連續記錄之解讀,本發明可以得到多只偵檢頭輻射脈衝時 間符合性(Coincidence)、間距、與寬度之資訊。透過簡單 之資料處理與演算步驟’本發明就可獲得造成環境輻射核 種比例與劑量率偵測結果。茲參照所圖示,詳細描述本發 明之原理與實施裝置系統重要組件設計。 X 首先說明本發明之閃爍體輻射偵檢頭設計。適用於本 Q 發明之輻射偵檢頭其構造如圖2所示,為一含有少量鉈雜 質之圓柱碘化鈉(Nal(Tl))閃爍體(201)搭配光電倍增管(2〇2) 所構成’其對輻射粒子彳貞檢機制須為.一對一脈衝轉換方 - 式’其直徑與厚度須能配合環境排放核種之最高能量有效 - 涵蓋需要,其閃爍體材質、光電倍增管光譜效率特性、表 面反射覆蓋處理、與體積效率,須能對輻射偵測對象(加 馬、X等射線)之種類與能量範圍執行有效之吸收與轉換, 還具有屏蔽阻隔非偵測對象(例:阿伐,貝他等射線)之放射 線與電磁輻射之干擾者。該偵檢頭其工作原理在於吸收加 201040570 • 馬射線(203)能量後,轉移為其共價鍵電子之動能,跳渡 鉈雜質造成之高能受激態再回到穩態放射出短促之脈^ 子(204) ’當脈衝光子被光電倍增管之光陰極收集,經由来 電效應打出約1〇7-1〇⑴顆光電子(2〇5),再透過十數級,各 • 級以高壓加速,撞擊其次陽極(2〇6)產生二次電子之乘數 大效果,最後可將光電子增加至1〇6倍。此可觀而短促( 20-50nsec)之光電子電流在外電路產生正比於輻射粒子被 吸收能量大小之電壓脈衝。再根據電壓脈衝之形狀、大1 〇 及發生頻次,對游離輻射場之輻射線種類與強度進行計〜 與辨識。典型輻射偵檢頭包括尺寸為直徑丨_3吋對背景^ 射反應效率超過50 cpS之閃爍體偵檢器,搭配之光電倍^ 管為日本濱松(Hamamatsu)株式會社出品型號R268或^ 等級之產品。如前述圖1所示,為將NaI(T1)閃爍體光電倍 增管所產生之輻射粒午類比信號自背景電子雜訊抽離出來 進行分析,偵測系統先使用設定低限為Vth之脈高鑑別電 路(105)將超過Vth、高度為Vp之類比脈衝信號(1〇4)轉換 〇 為含有輻射粒子能量吸收與閃爍發光事件特性、寬度為Tw 之邏輯脈衝(106)。設定低限為Vth之脈高鑑別電路,其作 用為在背景雜訊中將信號脈衝抽離。因Vp與Tw存在特定 " 之依存關係’利用其原理’對於邏輯脈衝可以用時序記錄 〜 器電路加以處理,下節說明設計原理與方法。 接下來說明,邏輯脈衝信號寬度與類比脈衝信號高度 之相關性。由圖1所示’光電倍增管搭配之信號處理電路 將光電倍增管因接受閃爍體吸收游離輻射粒子能量產生之 光脈衝所產生之類比電壓脈衝信號放大與定型,經低限鑑 9 201040570 別電路轉換為含有輻射粒子能量吸收與閃爍發光事件特性 之邏輯脈衝。本發明使用數位示波器同時量測記錄低限鑑 別電路輸入端之定型光電倍增管類比電壓脈衝信號波形與 輸出邏輯信號寬度。對於類比電壓脈衝信號波形,本發明 可以透過數值分析獲得以下列擬合公式: F(〇 = F0x(^-)(e^-e-^) (1) τ\ ~~ τ2 其中,v(t)是指類比電壓脈衝信號隨時間t變化之波 形函數,出現在等式右側之V〇、r 1 、r 2等符號均為擬 合參數。圖3所示為將Nal(Tl)閃爍體光電倍增管輸出經圖 1電路所產出之類比電壓脈衝信號使用擬合公式(1)代入適 當參數所計算出來之波形(粗黑實線)與實際以數位示波器 所測量出來之波形(細小黑點)比較。在證明公式(1)對不同 振幅之電壓脈衝波形完全符合後,本發明可以使用此公式 加上擬合參數計算出以下類比電壓脈衝高度(Vp)對鑑別器 輸出邏輯電壓脈衝寬度(Tw)之數學關係,如以下公式:The present invention can obtain information on the coincidence (Coincidence), spacing, and width of the plurality of detection heads by the simultaneous interpretation and continuous recording interpretation by the multiple analysis processing device (108). Through the simple data processing and calculation steps, the present invention can obtain the results of environmental radiation nuclear ratio and dose rate detection. The principles of the present invention and the design of important components of the implementation device system are described in detail with reference to the drawings. X First, the design of the scintillator radiation detecting head of the present invention will be described. The radiation detection head suitable for the invention of the present invention has the structure shown in Fig. 2, which is a cylindrical sodium iodide (Nal(Tl)) scintillator (201) with a small amount of antimony impurity and a photomultiplier tube (2〇2). It constitutes 'the radiation particle detection mechanism must be one-to-one pulse conversion method--the diameter and thickness must be compatible with the highest energy of the environmental emission nuclear species - covering the needs, its scintillator material, photomultiplier tube spectral efficiency Characteristics, surface reflection coverage processing, and volumetric efficiency must be able to perform effective absorption and conversion on the types and energy ranges of radiation detection objects (gamma, X, etc.), as well as shielding against non-detected objects (eg: Radiation and electromagnetic radiation interfere with cutting, beta and other rays. The detection head works by absorbing the energy of the 201040570 • horse ray (203), transferring it to the kinetic energy of its covalent bond electrons, jumping into the high-energy excited state caused by impurities, and then returning to the steady state to emit a short pulse. ^ 子(204) 'When the pulse photons are collected by the photocathode of the photomultiplier tube, about 1〇7-1〇(1) photoelectrons (2〇5) are emitted via the call-in effect, and then through ten levels, each level is high voltage Acceleration, impacting the secondary anode (2〇6) produces a multiplier effect of the secondary electrons, and finally increases the photoelectron to 1〇6 times. This appreciable and short (20-50 nsec) photoelectron current produces a voltage pulse in the external circuit proportional to the amount of energy absorbed by the radiating particles. According to the shape of the voltage pulse, the size of the large 〇 and the frequency of occurrence, the type and intensity of the radiation of the free radiation field are counted and identified. A typical radiation detection head consists of a scintillator detector with a diameter of 丨_3吋 and a background reaction efficiency of more than 50 cpS. The photo-electric tube is a model of the Japanese version of Hamamatsu Co., Ltd. R268 or ^ product. As shown in FIG. 1 above, in order to analyze the radiation grain-to-noise ratio signal generated by the NaI (T1) scintillator photomultiplier tube from the background electronic noise, the detection system first uses the pulse height set to the lower limit of Vth. The discrimination circuit (105) converts the pulse signal (1〇4), which exceeds Vth and has a height of Vp, into a logic pulse (106) having a characteristic of radiation particle energy absorption and scintillation event and having a width Tw. A pulse height discrimination circuit with a low limit of Vth is set, which acts to extract the signal pulses in the background noise. Because of the specific "dependence relationship between Vp and Tw, the principle can be used for the logic pulse to be processed by the timing record. The following section explains the design principle and method. Next, the correlation between the logical pulse signal width and the analog pulse signal height will be described. The signal processing circuit of the photomultiplier tube shown in Fig. 1 amplifies and stereotypes the analog voltage pulse signal generated by the photomultiplier tube by receiving the light pulse generated by the scintillator absorbing free radiation particle energy, and the low limit detection 9 201040570 Converted to a logic pulse containing the characteristics of the energy absorption and scintillation events of the radiant particles. The invention uses a digital oscilloscope to simultaneously measure the waveform of the analog voltage multiplier analog voltage pulse signal and the output logic signal at the input end of the low limit discrimination circuit. For the analog voltage pulse signal waveform, the present invention can obtain the following fitting formula through numerical analysis: F(〇= F0x(^-)(e^-e-^) (1) τ\ ~~ τ2 where v(t It refers to the waveform function of the analog voltage pulse signal as a function of time t. The symbols such as V〇, r 1 and r 2 appearing on the right side of the equation are fitting parameters. Figure 3 shows the photon of Nal(Tl) scintillator. The multiplier output is analogous to the voltage pulse signal produced by the circuit of Figure 1. The waveform calculated by the appropriate parameters (the thick black solid line) and the waveform actually measured by the digital oscilloscope (small black) are obtained by fitting the formula (1). Point) comparison. After demonstrating that formula (1) fully matches the voltage pulse waveforms of different amplitudes, the present invention can use this formula plus the fitting parameters to calculate the following analog voltage pulse height (Vp) to the discriminator output logic voltage pulse width. The mathematical relationship of (Tw), such as the following formula:
Vp = V〇xeT^/T +V, (2) 其中,出現在等式右側之V0、Vi 、r等符號均為擬 合參數。圖4所示為使用擬合公式(2)代入適當參數所計算 出來之類比電壓脈衝高度對鑑別器輸出邏輯電壓脈衝寬度 之轉換特性(粗黑實線)與實際以數位示波器所測量出來之 轉換特性(細小黑點)比較,可以證明彼此間存在固定之對 數函數關係。根據圖4,本發明是用精準高頻時鐘來測量 邏輯電壓脈衝寬度。若高頻時鐘之週期是Tdk,則利用公 式(2)做脈衝高度換算時,如公式(3)所示,本發明會發現使 201040570 用脈衝寬度測量換算脈衝高度時,僅有由士 、 與波型時間常數(τ )相關之固定之相對^里之週期(Tclk) 仰耵精確度,與佶用值 統類比/數位轉換之絕對精確度(例如不論脈衝含、從用得 何,一律是lmV)大不相同。此種特性與大部=大小如 之閃爍體/光電倍增管偵檢器解析度特性頗為°相=至溫運作 dV Ύ~Vp = V〇xeT^/T +V, (2) where the symbols such as V0, Vi, and r appearing on the right side of the equation are all fitting parameters. Figure 4 shows the conversion characteristic of the voltage pulse width of the discriminator output logic voltage (thick black solid line) calculated by the fitting equation (2) substituted with the appropriate parameters and the actual conversion measured by the digital oscilloscope. A comparison of characteristics (fine black dots) can prove that there is a fixed logarithmic function relationship between each other. According to Figure 4, the present invention measures the logic voltage pulse width with a precision high frequency clock. If the period of the high-frequency clock is Tdk, when the pulse height conversion is performed by the formula (2), as shown in the formula (3), the present invention finds that when the pulse width is measured by the pulse width measurement of 201040570, only the line, The fixed time period (Tclk) of the wave type time constant (τ) is related to the absolute accuracy of the analogy/digital conversion (for example, regardless of the pulse, whether it is used or not) lmV) is very different. This characteristic is quite different from the resolution of the majority of the size of the scintillator/photomultiplier detector. ° phase = temperature operation dV Ύ~
dT τ 丁 elk τ (3) ❹ Ο 至逾時序記錄ϋ之設計的部份,時序記錄器之 理係採取緩衝半職連續時序崎法解讀脈高鑑別電路轉 換輸出之邏輯脈衝信號。高頻計時脈衝計數器如圖5所 示,本發明以穩定之高頻(例:80ΜΗζ )時鐘(5〇2°)做為θ計數器 (503)汁數信號源輸入’將輪射偵測信號處理電路產出之^ 輯脈衝信號(501)做為閘控信號輸入,同時對所有陣列 Nal(Tl)閃爍體光電倍增管啟動時距計數,每半週期將計數 值依序存入預設之緩衝記憶體(504)之内,下半週期將計數 器歸零再重新計數並將結果儲存’完成一定時間或相當數 目邏輯脈衝信號記錄後’再將結果送入電腦(5〇5)做資料運 算分析。假設輻射事件所產生之脈衝為負向邏輯設計,則 圖5中緩衝記憶體記錄扣除啟動後第一筆錯誤記錄不計, 卓二、五、八…筆資料即為以時鐘量得之邏輯脈衝信號寬 度,而二加三、四加五、七加八…筆資料之和則是連續輕 射事件之間距。而比較所有閃燦體轄射偵檢頭每一負向邏 輯之始點時序即成為兩輻射事件符合性(Coincidence)之 判斷依據。對於某些具有雙光子同時放射之裂變特性放射 π 201040570 力如C:60母一次裂變放射兩顆M7MeV及1.33MeV ^ 5 #,i^^^^«^^(Coincidence),.l* 他射偵檢頭絕對效率不明情況下,獲得較其 他技術更為精確之活廑辞士 (ΙΤμ7)Τ^ , “本各 檢器之功能。 」建用以上貝枓,提昇閃爍體伯 ❹ 半週射事件之間距與計數率之相關性。由緩衝 衝寬法本:::到可推算出脈衝高度之脈 射脈衝事件之間距“ΐ:明:::=相鄰繼 機型態之輕射事件脈衝均可貞檢器’對隨 事件平均間L下之擬合公式(4)來推算量測到之輕射 I{{t)dt = (t)x ⑷ 日其中,I州是間距介於t和蘭之間輻射 二時序記錄法獲得之賴射脈 衝数目、,先》十刀佈特性。由圖上本發明可 件間距樣本數量為1_筆或5000筆,都麵^輪射事 松分布理論相當吻合。圖6 2 么式(4)波 輕射事件平均間距隨樣本數===實= -實驗點均標識出其1%之精確度 ^兄,圖中母 12 201040570 _ 僅需1000筆,自此以上,即使增加樣本數量,亦無益於精 確度之改善。 接下來說明,脈寬分佈能峰搜尋、核種辨識與活度量 測特性計算方法。由圖3、4及公式(2)可知,邏輯脈衝寬 度與輻射偵檢頭輸出之類比脈衝高度具有一定之數學關 係。由於類比脈衝高度與放射線粒子能量相關,因此本發 明亦可推論邏輯脈衝寬度之分布特性亦可獲得放射線粒子 能量分布特性資料。圖7-10即為以本發明方法,以80MHz ❹ 時鐘脈衝(Teik=12.5nsec)測量鋇一三三(Ba-133)、铯一三七 (Cs-137)、鈷六十(Co-60)以及銪一五二(Eu-152)等人造放 射性核種,經由2吋直徑x2吋厚圓柱體Nal(Tl)閃爍體輻 射偵檢頭測量一定時間,所得到之脈衝寬度分布結果。在 這些圖中,X轴數字(以下稱為控道編號j,Channel Number) 代表邏輯脈衝之寬度,例如20表示脈衝寬度為20xTclk, 即是250nsec,依此類推。Y軸數字(以下稱為控道之計數 值yj,Channel Counts)則代表對應控道編號j之邏輯脈衝寬 Q 度出現之次數。本發明為提高脈寬分布解析能力,在轉換 類比為邏輯脈衝時,採用兩組不同設定低限之脈高鑑別電 路,產生兩組不同之脈衝:使用較小低限電壓設定者為低 - 能脈衝(LoE),較高設定者為高能脈衝(HiE)。兩組脈衝 .. 同時產生且同步實施時序記錄,因此每一圖均有高低能量 兩種寬度分布結果。 與傳統之類比脈高解析式能譜分析儀相同,不同核種 之脈寬分布呈現不同能峰特性,每一能峰均代表特定核種 之專有衰變放射線。本發明可以透過不同之標準射源校正 13 201040570 程序’利用能峰特性々 辨識與活度運算功能=’毛展出放射性核種自動 圖1之全功能it +1為貫用之放射性監測系統。兹就 體輕射偵檢頭光:增率本:::何以_ 能量與等效劑量率二含有之加馬射線 相下段落分職明之。 ❹ Ο 及大::性加二::所觀察到之脈寬分布能峰位置、形狀 以求取放射性核種白叙亚與其放射光子能量及活度對照, 出一套能峰演算步驟,詳述如下: 月發展 分析=二數f平滑處理。為了建立後續的能峰搜尋與 /二A工,本發明必須先使用平滑方式來處理測量g 的平诉方獲 ㉝線。這裡本發明所使用 π:為攻小平方誤差法。不論是簡單之移動平均法 i疋:!:法’都是直覺式的並未考慮曲線本身的趨 錢r ^法可財慮到賴,湘放射性衰變 1之’陡來作平滑處理,也就是將其視為具有簡單指數 哀減(Slmple exponential decay)的特性曲線以減少因平滑處 理所造成之誤差。本發明所使用的最小平方誤差法平滑公 式如下: y 2jjV2>12yH+17y. +12y -3y. 35 (5) ,中j代表控道編號’ yj代表控道編號j所對應之計數 值y』代表經過鈾後五點平滑處理過之,結果如圖7_ 1 〇, 14 201040570 圖上散佈之實心點為由時序記錄器所測量出之脈寬分布數 據,而其連續實線即是由此公式所得到的能譜曲線,參考 圖9銘六十(Co-60)之低能分布特性,若未實施數據平滑處 理,數據將會過於雜亂而難以解析。 揭著進行步驟2、自動能峰位置搜尋。本發明所用之 自動能峰搜尋方法為二次微分法,其原理是利用能譜二次 微分後的值作判斷,若存在極大的負數,則表示該區域可 能有能峰出現。二次微分法最大優點為:(1)可將直線型的 〇 背景計數去除,(2)使得類似高斯函數的能峰更尖銳化,易 於數學處理。本專利所使用之峰值搜尋法即為二次微分 法,由於該能譜為數位化能譜,因此在這裡本發明稱之為 二次差分法。以下為二次差分法之公式 能譜一次差分公式·· ysj’ = ysj - ysj-i 能譜二次差分公式:ySj” = ySj’- ysj-i’ 依上一步驟得到一連續平滑曲線後,本發明將此能譜 曲線作一次與二次差分。由於二次差分結果出現最低負值 ❹ 的話,表示能譜曲線有可能在此範圍含有一能峰。且二次 差分值越負,則能峰越陡。因此本發明將二次差分值由低 而高排列,以便於作下一步的運算分析。為了確定此二次 、 差分最低處確實出現能峰,本發明將其前後區段(±5範圍之 " 一次差分值一併作比較,以確定能譜在此位置上球實出現 能峰。由於能岭的左半部為一向上斜坡,因此在一次差分 上會出現正值,能峰越陡,一次差分正值越高。能岭的右 半部為一向下斜坡,因此在一次差分上則會出現負值,能 ♦越陡,一次差分值越低(負)。 15 201040570 -根據以上的特性,本發明將一次差分值作排序,排序 方式為由高而低,其最高值與最低值都會利用來輔助判斷 負值一次差分能峰的真偽。由於高低能範圍僅有控 遏’考慮每-能譜能峰至少佔有約1G控道,本發明根據經 驗法則取能譜上二次差分最低負值的前二十名作為能峰判 斷標的’再以能譜中-次差分最低與最高值的前二十名, 來篩選與確認能譜能峰位置。 隨後進行步驟3、能峰全寬半高值(FWHM)計算。在搜 〇 尋到能♦位置後,為了更進一步確定此能峰為真,本發明 需要尋找能譜上此一能峰之左右控道半高點是否存在,如 果於能峰所在控道±10之範圍内無法尋得左右半高點控道 位置,則判定該能峰不符合能峰形狀,必須加以剔除。如 果左半高值與右半高值皆能找到的話,就可以較此能峰 為真。以圖9之C〇-60能譜為例,在低能段由於康普吞光 子分布的關係,會造成上-自動搜尋步驟上的判斷錯誤, 從而產生出許多偽能缘。在經過半高點控道筛選步驟後, ❹低此#又的偽能峰由於無法找到,因此全部被剔除。至於高 能段的結果也僅保留Co-60的兩個真實能峰。在確定能峰 左右半咼點控道位置存在後,本發明可以計算二者之$道 - 位置距離,此距離於能譜分析學名稱全寬半高值(Fu^ -Width Half Maximum,FWHM) ’為能譜能峰解析度之衡量 指標,可以應用於下一步驟能峰淨計數率之叶管。 步驟3之後’緊接著進行㈣4、能峰有效^(Regi〇n of Interests, ROI)計算。為計算能譜能峰淨計 統破化納偵檢頭活度娜率校準之基礎,十 16 201040570 /〇7。王由見半咼後,本發明會更進一步計算每個能峰的 大致噂,i依放射線粒子隨機性偵測理論,能譜能峰形狀 能峰分布模型,因此若“ 99.9%信賴區間來定義 FWHM。’不會超過能峰位置向左右各散開Μ倍之 向/右4發明於散開1.5倍之顺Μ範圍内沿能峰位置 做:能Γ二二存有最低點(峰谷),則以左右峰谷之範圍 Ο Ο 圍。料存有峰谷,則以左右L5倍之 做為旎峰有效範圍。 由於驟5、能峰淨計數率與活度效率因數計算。 兑b»日犯峰分布通常為一獨立的全能 =連續區之上,因此本發明必須利用 梯形面積代表背景值,因此能峰二心,其下方的 ,月不值後,即可獲得能峰值的淨計數值。 置測時間後便可制能峰料數率。數值除乂 九I 千古度攻率因數之物理 思義為峨化納偵檢頭對放射性核種高能糙 分^例如Co-60活度UBq,代表每秒: :::蜆變放射出^與1勒各一顆加馬粒子, ϋ加馬粒子之產率(Yield)分別為1Ό()%。 r=;7Mev能Γ爭計數率為。.lcps,則該能峰之活:效 率因數為㈣。在進行活度效率因數校正工作 標準射源緊貼蛾化納偵檢頭表面,形成2π量測, 壤其此時若總活度已知’對於標準射源能 ^數率除以-半總活度而獲得其料之特有活度^ 數0 17 201040570 接著,以步驟6對能峰能量校正與進行核種識別。在 核輻射偵測領域,任何放射性核種均可由其蜆變特性與放 射粒子之種類加以識別,典型範例表如表一所示。其中本 發明以半衰期來代表放射性核種之蜆變特性’以能量及產 率來代表放射粒子之種類。由公式(2)可知脈寬與粒子能量 之自然對數函數呈現直線相關性,因此於脈寬能譜圖上, 每一控道編號j均對應一能量值E,其對應關係可以由標 定不同標準射源之各種特性能峰位置後,依下列公式(6)以 〇 最小平方法擬合取得。其中’ A為擬合所得之斜率參數,B 為擬合所得之戴距參數: ln(E)= Axj + B (6) 表二所示即為本發明全功能環境輻射監測裝置所使用 之碘化鈉偵檢頭以各種標準射源能譜(圖7_10)為例,依照 前述演算步驟所獲得之校正結果。圖U為高低能段使用公 式(6)對上述標準射源能譜量測結果擬合後之比較。當本發 明以該碘化鈉偵檢頭進行環境核種活度偵測時,在能譜取 〇 得以後,本發明便可依步驟一〜四搜尋能峰與進行淨計數率 計算。對能峰位置可以利用校正所得之擬合'參數按公式(6) 回推其能峰能量,再根據能峰能量查表一以辨別可能之核 、種。實務上,本發明通常對環境所可能含有之放射性核種 、均已限縮至十數種或更少,而且絕大比例可有如表二所示 之完整參數提供換算,因㈣_作正確度足以滿足法規 要求。 表一、放射性核種蜆變特性與光子種類典型範例表 18 201040570dT τ □ elk τ (3) ❹ 至 To the part of the design of the time-series recording, the timing recorder uses a buffered half-time continuous time series to interpret the logic pulse signal of the pulse height discrimination circuit conversion output. The high-frequency timing pulse counter is shown in FIG. 5. The present invention uses a stable high-frequency (eg: 80 ΜΗζ) clock (5 〇 2 °) as the θ counter (503) juice number source input 'to process the shot detection signal The pulse signal (501) of the circuit output is used as the gate signal input, and the time interval of all the array Nal(Tl) scintillator photomultipliers is counted, and the count value is sequentially stored in the preset buffer every half cycle. Within the memory (504), the counter is reset to zero in the second half of the cycle and then re-counted and the result is stored 'completed for a certain period of time or a considerable number of logical pulse signals recorded' and then sent to the computer (5〇5) for data analysis . Assuming that the pulse generated by the radiation event is a negative logic design, the first error record after the buffer memory record deduction is started in Figure 5, the second, fifth, and eighth pen data is the logical pulse signal width obtained by the clock amount. And two plus three, four plus five, seven plus eight ... the sum of the data is the distance between consecutive light shot events. Comparing the starting point timing of each negative logic of all the flash detection heads becomes the basis for the judgment of the two radiation events (Coincidence). For some fission characteristics with two-photon simultaneous emission, π 201040570 force such as C: 60 female primary fission radiation two M7MeV and 1.33MeV ^ 5 #,i^^^^«^^(Coincidence), .l* If the detection head is absolutely unclear, it will be more accurate than other technologies. (ΙΤμ7)Τ^, “The function of each detector.” Use the above bellows to enhance the scintillator. The correlation between the distance between events and the count rate. From the buffering widening method::: to the pulse pulse event that can be inferred from the pulse height, the distance between the pulse events of the pulse height: "ΐ:明:::=the adjacent relay type can be detected by the detector" The fitting formula (4) under the average interval L is used to estimate the light shot I{{t)dt = (t)x (4) day, where I state is the interval between t and blue. The number of the ray-receiving pulses obtained, first, the ten-knife characteristics. From the figure, the number of samples of the detachable parts of the invention is 1_pen or 5000, and the theory of the plane-and-rolling loose distribution is quite consistent. Figure 6 2 (4) The average distance of wave light incidents with the number of samples === real = - the experimental points all indicate the accuracy of 1% ^ brother, the picture in the mother 12 201040570 _ only need 1000 pens, since then, even if the sample is increased The quantity is also not conducive to the improvement of accuracy. Next, the pulse width distribution energy peak search, nuclear identification and live measurement characteristics calculation method. From Fig. 3, 4 and formula (2), the logic pulse width and radiation detection The analog output has a mathematical relationship with the pulse height. Since the analog pulse height is related to the radiation particle energy, The present invention can also infer that the distribution characteristics of the logical pulse width can also obtain the data of the radiation particle energy distribution characteristics. Figure 7-10 shows the method of the present invention, using a 80 MHz 时钟 clock pulse (Teik = 12.5 nsec) to measure the 钡一三三(Ba -133), 铯一三七(Cs-137), cobalt sixty (Co-60), and 铕152 (Eu-152) and other artificial radioactive nucleus, through 2吋 diameter x2 圆柱 thick cylinder Nal (Tl) The scintillator radiation detecting head measures the result of the pulse width distribution obtained for a certain period of time. In these figures, the X-axis number (hereinafter referred to as the channel number, Channel Number) represents the width of the logic pulse, for example, 20 indicates that the pulse width is 20xTclk, that is, 250nsec, etc. The Y-axis number (hereinafter referred to as the track count value yj, Channel Counts) represents the number of times the logical pulse width Q of the corresponding track number j appears. The present invention is to increase the pulse width. Distribution resolution capability, when the conversion analogy is a logic pulse, two sets of different low-limit pulse height discrimination circuits are used to generate two different pulses: the lower-lower voltage setting is low-energy pulse (LoE). High setting is high Pulse (HiE). Two sets of pulses: simultaneous generation and simultaneous timing recording, so each graph has two width and width distribution results. Same as the traditional analog high-resolution analytical spectrum analyzer, different nuclear species The pulse width distribution exhibits different energy peak characteristics, each of which represents a specific decay radiation of a particular nuclear species. The present invention can be calibrated by different standard sources 13 201040570 Procedure 'Using energy peak characteristics 々 Identification and activity calculation function = ' The hair exhibits a radioactive nuclear species. The full-featured it +1 of Figure 1 is a pervasive radioactive monitoring system. In the case of light detection, the light is increased: Ben::: Why _ Energy and equivalent dose rate II contain the Jiama ray. ❹ Ο and large:: Sex plus two:: The observed pulse width distribution peak position and shape to obtain the radioactive nuclear species Baisiya and its radiation photon energy and activity comparison, a set of energy peak calculation steps, detailed As follows: Monthly development analysis = two-number f smoothing. In order to establish a subsequent energy peak search and /A work, the present invention must first use the smoothing method to process the level of the measure g to obtain 33 lines. Here, the π used in the present invention is a small square error method. Whether it is a simple moving average method, i疋:!: The law is an intuitive one. It does not consider the trend of the curve itself. The method can be used to smooth the smoothing of the radioactive decay 1 Think of it as a characteristic curve with a simple exponential decay to reduce the error caused by the smoothing process. The least square error method smoothing formula used in the present invention is as follows: y 2jjV2 > 12yH + 17y. +12y -3y. 35 (5) , where j represents the track number ' yj represents the count value y corresponding to the track number j 』 The representative is smoothed by five points after uranium. The result is shown in Fig. 7_ 1 〇, 14 201040570 The solid point scattered on the graph is the pulse width distribution data measured by the time series recorder, and the continuous solid line is the formula The obtained energy spectrum curve refers to the low energy distribution characteristic of Fig. 9 (Co-60). If data smoothing is not implemented, the data will be too messy and difficult to analyze. Step 2, automatic peak position search. The automatic energy peak searching method used in the present invention is a quadratic differential method, and the principle is to use the value after the second derivative of the energy spectrum for judgment. If there is a large negative number, it indicates that the region may have a peak. The main advantages of the second derivative method are: (1) the linear 〇 background count can be removed, and (2) the energy peak similar to the Gaussian function is sharpened and is easy to be mathematically processed. The peak search method used in this patent is the second derivative method. Since the energy spectrum is a digital energy spectrum, the present invention is referred to herein as the second difference method. The following is the formula for the second difference method. The first difference formula is · ysj' = ysj - ysj-i The second difference formula of the energy spectrum: ySj" = ySj'- ysj-i'. After obtaining a continuous smooth curve according to the previous step. According to the present invention, the energy spectrum curve is subjected to primary and secondary differences. Since the second differential result has the lowest negative value ❹, it indicates that the energy spectrum curve may have a peak in this range, and the secondary difference value is negative, The steeper the energy peak is. Therefore, the present invention arranges the second difference values from low to high for the next step of operation analysis. In order to determine the secondary peak, the energy peak appears at the lowest point, the present invention has its front and rear sections ( The ±5 range " one difference value is compared together to determine the energy peak of the spectrum at this position. Since the left half of the energy is an upward slope, a positive value will appear on the difference. The steeper the energy peak is, the higher the positive difference is. The right half of the energy is a downward slope, so there will be a negative value on one difference, and the steeper the energy, the lower the differential value (negative). 15 201040570 - according to the above characteristics, the present invention The first difference value is sorted, the ordering method is high and low, and the highest value and the lowest value are used to assist in judging the authenticity of the negative differential energy peak. Since the high and low energy ranges are only controlled, the per-energy spectrum is considered. The energy peak occupies at least about 1G control track. According to the rule of thumb, the present invention takes the top 20 of the lowest difference of the second difference of the energy spectrum as the energy peak criterion, and then the first two of the lowest and highest values of the energy spectrum. Ten, to screen and confirm the energy peak position. Then proceed to step 3, the full width and width of the peak (FWHM) calculation. After searching for the position of the ♦, in order to further determine this energy peak is true, The invention needs to find out whether the half-high point of the left and right control tracks of the energy peak is present, and if the position of the left and right high-level control tracks cannot be found within the range of ±10 of the control peak, it is determined that the energy peak does not meet The peak shape must be removed. If the left half-height value and the right half-height value can be found, the peak can be true. The C〇-60 spectrum of Figure 9 is taken as an example. The relationship between the distribution of photons and the photons will cause The judgment error in the search step is generated, and a lot of pseudo-energy edges are generated. After the half-high point control channel screening step, the pseudo-energy peaks that depreciate this # are not found because they cannot be found. Therefore, the results of the high energy segment are eliminated. Only the two true energy peaks of Co-60 are retained. After determining the position of the left and right half-point control tracks of the energy peak, the present invention can calculate the $way-position distance of the two, which is the full width of the energy spectrum analysis name. The semi-high value (Fu^-Width Half Maximum, FWHM) is a measure of the spectral peak resolution, which can be applied to the leaf tube with the net peak count rate in the next step. After step 3, 'following (4) 4, can The peak is valid ^ (Regi〇n of Interests, ROI) calculation. In order to calculate the spectrum of energy spectrum peaks, the basis of the calibration of the detection head activity rate, 10 16 201040570 /〇7. After Wang You sees a half-turn, the present invention will further calculate the approximate 噂 of each energy peak, i according to the radiation particle randomness detection theory, the energy spectrum peak shape energy peak distribution model, so if "99.9% confidence interval to define FWHM. 'Do not exceed the peak position of the peak to the left and right. / 之 / / 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明 发明The range of the peaks and valleys is Ο 。. When there are peaks and valleys in the material, the left and right L5 times is used as the peak effective range. Because of the peak 5, the peak peak rate and the activity efficiency factor are calculated. The peak distribution is usually an independent omnipotent = continuous area. Therefore, the present invention must utilize the trapezoidal area to represent the background value, so that the peak can be peaked, and below it, after the month is not worth, the net count value of the peak value can be obtained. After the time is set, the peak rate can be determined. The value of the factor is the physics of the nine-year-old attack rate factor, which is the high-energy roughness of the radioactive nuclear species, such as the Co-60 activity UBq. Per second: ::: 蚬 放射 emit ^ and 1 勒 each plus horse particles, ϋ 加The yield of the particles (Yield) is 1Ό()%, respectively. r=; 7Mev can compete for the counting rate. .lcps, then the energy of the energy peak: the efficiency factor is (4). In the activity efficiency factor correction work standard source Close to the surface of the moth-detecting head, forming a 2π measurement, and if the total activity is known at this time, the specific activity of the material is obtained by dividing the standard source energy rate by the --half total activity^ Number 0 17 201040570 Next, energy peak correction and nuclear identification are performed in step 6. In the field of nuclear radiation detection, any radioactive nuclear species can be identified by its enthalpy characteristics and the type of radiation particles. The typical example table is shown in Table 1. In the present invention, the half-life is used to represent the enthalpy characteristic of the radioactive nucleus, and the type of the radiating particle is represented by energy and productivity. From the formula (2), the natural logarithm function of the pulse width and the particle energy exhibits a linear correlation, so On the pulse width spectrum, each control number j corresponds to an energy value E, and the corresponding relationship can be determined by calibrating various characteristic peak positions of different standard sources according to the following formula (6). Acquired. Among them 'A Fitting the obtained slope parameter, B is the fitting distance parameter: ln(E)= Axj + B (6) Table 2 shows the sodium iodide detection used in the full-function environmental radiation monitoring device of the present invention. The head uses various standard source energy spectra (Fig. 7_10) as an example, according to the calibration results obtained by the above calculation steps. Figure U is the high and low energy segment using the formula (6) to fit the above standard source energy spectrum measurement results. When the present invention uses the sodium iodide detection head to perform environmental nuclear activity detection, the present invention can calculate the energy peak and perform the net count rate according to steps 1 to 4 after the energy spectrum is obtained. The energy peak position can be corrected by the corrected fitting parameter according to formula (6), and then the energy peak energy can be checked according to the energy peak energy to identify the possible nuclear and species. In practice, the present invention generally limits the amount of radioactive nuclear species that may be contained in the environment to a dozen or less, and the vast majority may provide conversions for the complete parameters as shown in Table 2, because (4) _ is correct enough Meet regulatory requirements. Table 1. Table of typical examples of radioactive nuclear species' enthalpy characteristics and photon species 18 201040570
核種 半衰期 光子能量 (keV) 光子產率 (%) Co-57 271.77 天 122 85.5 136.5 10.7 Co-60 5.271 年 1332.5 99.98 1173.2 99.9 34 123 Ba-133 10.54 年 81 34 356 80 Cs-137 30.0 年 30 7 662 85 45 75 122 28 344 27 Eu-152 13.33 年 779 13 964 15 1112 14 1408 21 1-131 8.04 天 364.5 81.2 637 7.27 284.3 6 80.2 2.6 19 201040570 722.9 1.8 29-34 4.9 Mn-54 312.2 天 834.8 99.98 Am-241 432.7 年 59.5 35.7 12-21 39.5 1099 56.5 Fe-59 44.5 天 1291 43.2 192.3 3.1 表二、蛾化鈉偵檢頭能譜與核種校正結果一覽表 偵檢頭 -序號 工作電 壓 時鐘頻 率 LoE HiE 校正曰 期 2x2 鈉 SAG552 820V 80MHz 25mV 540mV 06/03/08 校正核種 (活度) 光子 能量/產率 keV(%) 低能段 能峰 (控道編 號) 南能段 能峰 (控道編 號) 能峰 淨計數率 (cps) 效率因 素 (淨計數· 率/活度) Ba-133 (5870Bq) 34(123%) 74 氺 1294 0.22 81(34%) 123 氺 501 0.086 356(80%) 201 氺 1481 0.252 Cs-137 30(7%) 75 氺 20 201040570 (9915Bq) 662(85%) 232 氺 1148 0.116 47 1197 0.121 Eu-152 (7895Bq) 45(75%) 85 氺 1275 0.161 122(28%) 142 氺 575 0.072 344(27%) 197 氺 333 0.042 779(13%) 本 58 77 0,01 964(15%) 氺 71 126 0.016 1112(14%) 氺 78 92 0.012 1408(21%) 氺 91 46 0.006 Co-60 (158Bq) 1173(100%) 氺 80 5.5 0.035 1332(100%) 氺 87 4.12 0.026 低能段 能量<> 控道 換算係數 A斜率值 0.0186 B截距值 2.15 - 低能段 能量<> 控道 換算係數 A斜率值 氺 0.0176 B截距值 氺 5.65 接著說明多只偵檢頭辨識輻射排放方位方法。本發明 對於環境排放之陣列碘化鈉光電倍增管脈衝信號,除了透 過個別計數率與脈寬能譜之來測量等效劑量率、加馬輻射 核種與活度外,還可以利用各個偵檢頭指向性與排列方 式,按彼此時序分佈統計特性尋求放射性物質排放方位之 可能性。例如將偵檢頭依放射狀排列,比較偵檢頭量測值 21 201040570 隨時間變化相互闕係即可 μ 知技術,此處不做贅述。工易推估方位賢料。因為此為習 接下來說明利用能蹲計傘 納閃爍體偵檢頭量謂環境箄二巧=羊方法。使用碘化 體高密度與高原子序=率時’她^ 率與人體組織差異越大二除子之吸收效 ο 統均將核種量測盘等之環境輕射測量系 用於等效劑量率測量之偵檢頭,大多 ,組織之低密度、低原子序之材質構成,如充氣式= =矣盍袼管或石夕二極管等。改採用這些低偵測效率偵檢 二率測量最重要之缺點為不但增加系統硬 射:C: ’而且精準度會大幅降低’提高了環境輻 射監測糸統之作業成本。 〇 曰本發明採用能譜與劑量率一次量測之方法解決光子能 量對等效劑量率測量效率之影響問題。其主要之工作原理 在於依碘化鈉閃爍體之平均吸收能量變化採用不同之效率 係數,自動修正碘化鈉閃爍體對人體組織之吸收效率差 異。此處基於運算便利,本發明以平均控道編號(脈寬)勺> 來代表平均吸收能量,其計算公式為: 256 = — (7) 公式(7)中,j代表控道編號,yj代表脈寬能譜中對應 22 201040570 所-量之計數次數。本發明採用不同能量之射 校:所求得效率係數對光子能量之變化特性,圖12為 ^出之效率織對平均控道編號(脈寬)結果。 以下任貞檢系統實施裝置,電腦主控制器必須負責 Ο Ο L,射脈衝資料擷取:電腦在與輻射偵檢頭完成硬體 j線及測試後,域作者透過電腦雜界面依陣列 ,檢頭序號輸人各自Μ校正之賴率、脈寬分佈 倉畺、核種、效率因數、劑量率換算等對照 卢\^些數值如附表二所示,均為賴射偵檢頭與信號 =電路,以離線狀況下,用指定之標準輻射校測 =後,由工作站電腦演算獲得。此外,輻射防護 =制參數如核種、活度與劑量率預警及警報限值 專等。上述參數於確認無謓後,存入非 :記憶體之中。接著程式啟動由電腦執行透過數: 類比轉換界面完檢頭卫作參數值之設定,缺 =用轄射偵檢頭,同步進人連續時序記錄資料二 2.:身料t析:當完成陣列光電倍增管同步緩衝半週 =連續時序記錄資料組測量至足約數目與時間 二’即可命令電腦應用時序記錄資料組執行受測 每所環境劑量率與其内污染射源之種類、活度及 位^。等演算作業。其目的在於對計數資料ς, 从-表及多4比對方法’得到有關受測環 π染輻射之種類及方位之最可能之評估。 23 201040570 3. 電腦輻射場強劑量率值、推估核種、可能位置顯 示與警報:當所計測輻射等效劑量率資料被確認 可信並完成確認後,程式即可命令電腦依人員輻 射防護管制作業之要求,執行輻射場強劑量率 值、推估核種、活度、可能位置顯示與警報,設 計上也可做特定資料存錄之功能。 4. 數值資料傳錄:為配合輻射偵測系統資料庫之建 立與疑難計測資料之再處理,電腦必須能執行與 0 他種電腦主機數據連線與資料傳錄等功能。典型 之軟體程式流程圖參見圖13。 惟以上所述者,僅為本發明之實施例,當不能以之限 制本發明範圍。即大凡依本發明申請專利範圍所做之均等 變化及修飾,仍將不失本發明之要義所在,亦不脫離本發 ' 明之精神和範圍,故都應視為本發明的進一步實施狀況。 〇 24 201040570 【圖式簡單說明】 圖1為本發明之全功能環境加馬輻射監測儀設計圖。 圖2為輪射偵檢頭構造不意圖。 圖3係為將閃爍體光電倍增管輸出經圖1電路所產出之 類比電壓脈衝信號使用擬合公式(1)代入適當參 數所計算出來之波形(粗黑實線)與實際以數位示 波器所測量出來之波形(細小黑點)比較圖。 〇 圖4係為使用擬合公式(2)代入適當參數所計算出來之 類比電壓脈衝高度對鑑別器輸出邏輯電壓脈衝寬 度之轉換特性(粗黑實線)與實際以數位示波器所 測量出來之轉換特性(細小黑點)比較圖。 圖5係為脈衝時序記錄器電路圖。 圖6係為使用缓衝半週期連續時序記錄法獲得之輻射脈 衝數目統計分佈特性示意圖。 ◎ 圖7係為本發明設計脈衝時序記錄器電路,以80MHz時 鐘脈衝(Tclk=l 2.5nsec)測量鋇一三三(Ba-133)人 造放射性核種,經由2吋直徑x2吋厚圓柱體Nal(Tl) 閃爍體輻射偵檢頭測量一定時間,所得到之脈衝 寬度分布結果。 圖8係為本發明設計脈衝時序記錄器電路,以80MHz時 鐘脈衝(Tclk=12.5nsec)測量铯一三七(Cs-137)人 造放射性核種,經由2吋直徑x2吋厚圓柱體Nal(T1) 25 201040570 閃爍體輻射偵檢頭測量一定時間,所得到之脈衝 寬度分布結果。 圖9係為本發明設計脈衝時序記錄器電路,以80MHz時 鐘脈衝(Tclk=12.5nsec)測量鈷六十(Co-60)人造 放射性核種,經由2吋直徑x2吋厚圓柱體Na[(Tl) 閃爍體輻射偵檢頭測量一定時間,所得到之脈 衝寬度分布結果。 〇 圖10係為本發明設計脈衝時序記錄裔電路,以80MHz 時鐘脈衝(Tclk=12.5nsec)測量銪一五二(Eu-152) 人造放射性核種,經由2对直徑x2忖厚圓柱體 Nal(Tl)閃爍體輻射偵檢頭測量一定時間,所得 到之脈衝寬度分布結果。 ' 圖11係為高低能段脈寬頻譜使用公式(6)對圖7-10各種 標準射源能譜量測結果擬合後之比較。 ❹ 圖12係為利用Am-241、Co-57、Cs-137與Co-60等標準 射源校正所得出之效率係數對平均控道編號(脈 .. 寬)結果。 .. 圖13係為本發明之全功能環境輻射監測實施裝置,微電 腦主控制器必須負責典型之軟體程式流程圖。 【主要元件符號說明】 101-閃爍體輻射偵檢器 26 201040570 102- 輻射偵檢器工作所需之高壓供應器 103- 高度為Vp之輻射偵測類比脈衝串列 104- 設定低限為Vth之脈高鑑別電路 105- 鑑別後轉換成寬度為Tw之輻射偵測邏輯脈衝串列 106- 進行時序記錄所需之精準時鐘脈衝 107- 同步脈衝時序記錄器 10 8 -時序記錄資料擷取與演算分析處理裝置 201- 碘化鈉閃爍體 〇 202- 搭配碘化鈉閃爍體之光電倍增管 203- 入射放射線粒子 204- 閃爍體分子吸收粒子能量受激發射之短促光子脈衝 205- 脈衝光子被光電倍增管之光陰極收集打出之光電子 206- 以高壓加速產生二次電子之乘數放大效果之次陽極 501- 做為計數器閘控信號輸入之輻射偵測邏輯脈衝信號 502- 做為計數器計數信號源輸入穩定之高頻時鐘 q 5 0 3 -由雙向閘控信號控制之半週期脈寬時鐘計數器 504-每半週期將計數值依序存入預設之緩衝記憶體 • 505-將結果做資料運算分析之處理裝置 27Nuclear half-life photon energy (keV) photon yield (%) Co-57 271.77 day 122 85.5 136.5 10.7 Co-60 5.271 year 1332.5 99.98 1173.2 99.9 34 123 Ba-133 10.54 year 81 34 356 80 Cs-137 30.0 year 30 7 662 85 45 75 122 28 344 27 Eu-152 13.33 year 779 13 964 15 1112 14 1408 21 1-131 8.04 day 364.5 81.2 637 7.27 284.3 6 80.2 2.6 19 201040570 722.9 1.8 29-34 4.9 Mn-54 312.2 days 834.8 99.98 Am- 241 432.7 59.5 35.7 12-21 39.5 1099 56.5 Fe-59 44.5 days 1291 43.2 192.3 3.1 Table 2, moth sodium detection head energy spectrum and nuclear species calibration results list detection head - serial operating voltage clock frequency LoE HiE calibration period 2x2 sodium SAG552 820V 80MHz 25mV 540mV 06/03/08 Calibration nuclear species (activity) Photon energy / yield keV (%) Low energy segment energy peak (control track number) South energy segment energy peak (control channel number) Energy peak net count rate (cps) Efficiency factor (net count·rate/activity) Ba-133 (5870Bq) 34(123%) 74 氺1294 0.22 81(34%) 123 氺501 0.086 356(80%) 201 氺1481 0.252 Cs-137 30(7 %) 7 5 氺20 201040570 (9915Bq) 662(85%) 232 氺1148 0.116 47 1197 0.121 Eu-152 (7895Bq) 45(75%) 85 氺1275 0.161 122(28%) 142 氺575 0.072 344(27%) 197 氺333 0.042 779 (13%) 58 77 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ) 氺80 5.5 0.035 1332(100%) 氺87 4.12 0.026 Low energy energy <> Control channel conversion coefficient A slope value 0.016 B intercept value 2.15 - low energy energy <> Control channel conversion coefficient A slope value 氺0.0176 B intercept value 氺 5.65 Next, the method of identifying the radiation discharge azimuth by multiple detection heads will be described. The invention provides an array of sodium iodide photomultiplier pulse signals for environmental discharge, in addition to measuring the equivalent dose rate, the gamma radiation nucleus and activity through individual counting rate and pulse width spectrum, and also utilizing various detection heads. Directionality and arrangement, the possibility of seeking radioactive material emission orientation according to the statistical characteristics of time series distribution. For example, the detection heads are arranged in a radial manner, and the detection head measurement values are compared. 21 201040570 It is possible to change the relationship with time, so that the technology is not described here. Work Yi estimated the position and good prospects. Because this is a habit, the next step is to use the energy meter to detect the amount of the smear. When using high-density and high atomic order of the iodide, the difference between the rate of her and the human tissue is greater. The absorption efficiency of the diploid is used for the equivalent dose rate of the nuclear measurement instrument. The detection heads of the measurement are mostly composed of low-density, low-atomic materials of the structure, such as inflatable == 矣盍袼 tube or Shi Xi diode. The most important shortcoming of using these low-detection efficiency detections is that not only the system hardening is increased: C: ' and the accuracy is greatly reduced', which increases the operating cost of the environmental radiation monitoring system. 〇 曰 The invention uses the method of energy spectrum and dose rate measurement to solve the problem of the effect of photon energy on the measurement efficiency of the equivalent dose rate. The main working principle is to automatically correct the difference in absorption efficiency of sodium iodide scintillator to human tissue by using different efficiency coefficients according to the average absorption energy of sodium iodide scintillator. Here, based on the convenience of operation, the present invention represents the average absorbed energy by the average track number (pulse width) scoop >, and the calculation formula is: 256 = - (7) In the formula (7), j represents the track number, yj Represents the number of counts in the pulse width spectrum corresponding to 22 201040570. The present invention employs different energy stimuli: the obtained efficiency coefficient versus photon energy variation characteristics, and Fig. 12 is the efficiency woven pair average track number (pulse width) result. The following equipment is used to implement the inspection system. The main controller of the computer must be responsible for Ο , L, and the pulse data is captured: after the computer completes the hardware j-line and test with the radiation detection head, the domain author checks the array through the computer interface. The first serial number is input to the respective correction rate, the pulse width distribution, the nuclear species, the efficiency factor, the dose rate conversion, etc. The values are as shown in the attached table, and both are the detection head and the signal = circuit. In the offline condition, the radiation test with the specified standard = after the calculation by the workstation computer. In addition, radiation protection = system parameters such as nuclear species, activity and dose rate warnings and alarm limits. The above parameters are stored in non-memory after confirmation of innocence. Then the program starts by the computer to execute the number of transmission: analog conversion interface to complete the setting of the parameter value of the head guard, lack of = use the detection head, synchronize into the continuous time record data 2. 2. Photomultiplier tube synchronous buffer half cycle = continuous time series recording data set measurement to the number of times and time two ' can command the computer application time series record data group to perform the measured environmental dose rate and the type and activity of the internal pollution source Bit ^. And other calculations. The purpose is to obtain the most probable assessment of the type and orientation of the π-stained radiation of the ring under test for the count data 从, from the - and multiple 4 comparison methods. 23 201040570 3. Computer radiation field strength dose rate value, estimated nuclear species, possible position display and alarm: When the measured radiation equivalent dose rate data is confirmed and confirmed, the program can command the computer to comply with the personnel radiation protection control The requirements of the operation, the radiation field strength dose rate value, the estimated nuclear species, activity, possible position display and alarm, can also be designed to record the specific data. 4. Numerical data transmission: In order to cooperate with the establishment of the radiation detection system database and the re-processing of the difficult measurement data, the computer must be able to perform functions such as data connection and data transmission with the computer host. See Figure 13 for a typical software program flow diagram. However, the above is only an embodiment of the present invention, and the scope of the present invention is not limited thereto. It is to be understood that the scope of the present invention is not limited by the spirit and scope of the present invention, and should be considered as further implementation of the present invention. 〇 24 201040570 [Simple description of the diagram] Figure 1 is a design diagram of the full-function environment plus horse radiation monitor of the present invention. Figure 2 is a schematic view of the construction of the wheel detection head. Figure 3 is a waveform (bold black solid line) calculated by substituting the fitting equation (1) into the appropriate parameter by the output of the scintillator photomultiplier tube through the circuit of Fig. 1 and the actual digital oscilloscope The measured waveform (small black dots) is compared. Figure 4 is the conversion characteristic of the voltage pulse width of the discriminator output logic voltage width (the thick black solid line) calculated by using the fitting formula (2) into the appropriate parameters and the actual conversion measured by the digital oscilloscope. Characteristic (small black dots) comparison chart. Figure 5 is a circuit diagram of a pulse timing recorder. Fig. 6 is a diagram showing the statistical distribution characteristics of the number of radiation pulses obtained by the buffer half-cycle continuous time series recording method. ◎ Figure 7 is a pulse timing recorder circuit designed according to the present invention, which measures the artificial radioactive nucleus of Ba-133 by a clock pulse of 80 MHz (Tclk=l 2.5nsec) through a 2吋 diameter x2 thick cylinder Nal ( Tl) The scintillation radiation detection head measures the result of the pulse width distribution obtained for a certain period of time. 8 is a pulse timing recorder circuit designed according to the present invention, which measures an artificial radioactive nucleus of C37-137 with a clock pulse of 20 MHz (Tclk=12.5 nsec), via a 2吋 diameter x2 thick cylinder Nal (T1). 25 201040570 The scintillation radiation detection head measures the result of the pulse width distribution obtained for a certain period of time. 9 is a pulse timing recorder circuit designed according to the present invention, measuring a cobalt sixty (Co-60) artificial radioactive nucleus with an 80 MHz clock pulse (Tclk=12.5 nsec), via a 2 吋 diameter x2 吋 thick cylinder Na[(Tl) The scintillator radiation detection head measures the result of the pulse width distribution obtained for a certain period of time. FIG. 10 is a circuit diagram of a pulse timing recording circuit of the present invention, which measures an artificial radioactive nucleus of Eu-152 (Eu-152) with an 80-MHz clock pulse (Tclk=12.5nsec), via two pairs of diameter x2 thick cylinders Nal (Tl The scintillator radiation detection head measures the result of the pulse width distribution obtained for a certain period of time. Figure 11 is a comparison of the high- and low-energy pulse width spectrum using equation (6) to the various standard source spectrum measurements of Figure 7-10. ❹ Figure 12 shows the results of the average control channel number (pulse .. width) obtained by using the standard source corrections such as Am-241, Co-57, Cs-137, and Co-60. Fig. 13 is a full-featured environmental radiation monitoring implementation device of the present invention, and the micro-computer main controller must be responsible for a typical software program flow chart. [Main component symbol description] 101-Scintillator radiation detector 26 201040570 102- High-voltage supply required for radiation detector operation 103- Radiation detection analog pulse train with height Vp 104- Set low limit to Vth Pulse height discrimination circuit 105- After conversion, it is converted into radiation detection logic pulse train with width Tw 106- Precision clock pulse required for timing recording 107- Synchronous pulse timing recorder 10 8 - Time series recording data acquisition and calculation analysis Treatment device 201 - Sodium iodide scintillator 〇 202 - Photomultiplier tube 203 with sodium iodide scintillator - Incident radiation particles 204 - Scintillator molecule absorbing particle energy Short-acting photon pulse 205 - Pulse photon is photomultiplier The photocathode collects the photoelectron 206 - the secondary anode 501 that accelerates the multiplier by the high voltage to generate the secondary electron. The radiation detection logic pulse signal 502 as the counter gate signal input is stable as the counter counter signal source input. The high frequency clock q 5 0 3 - the half cycle pulse width clock counter 504 controlled by the bidirectional gate control signal - the count value is sequentially stored into the preset every half cycle Buffer memory • 505- results do arithmetic processing data analysis of the device 27