本文選題：波形采樣　切入點(diǎn)：數(shù)字波形分析　出處：《中國科學(xué)院研究生院(近代物理研究所)》2016年博士論文

【摘要】：正電子發(fā)射斷層成像(Positron Emission Tomography,PET)可以實(shí)現(xiàn)對(duì)重離子束輻照劑量分布與定位的監(jiān)測(cè),在PET中引入飛行時(shí)間信息(Time of Flight,TOF)可以減少圖像重建時(shí)的數(shù)據(jù)處理時(shí)間,改善影像質(zhì)量。在研制應(yīng)用于重離子治癌監(jiān)測(cè)的TOF-PET系統(tǒng)時(shí),傳統(tǒng)的分立式的電子學(xué)讀出系統(tǒng)因規(guī)模龐大、電路復(fù)雜、功耗高、測(cè)量精度低以及可靠性差等問題,無法滿足TOF-PET系統(tǒng)的需求。因此,需要設(shè)計(jì)開發(fā)新的低成本,高集成度的讀出電子學(xué)系統(tǒng)�；谶@一需求,我們與核電子學(xué)研究組合作開發(fā)了以基于SCA(Switched Capacitor Array)的DRS4芯片(Dumino Ring Sampler version 4)為核心的數(shù)字化波形采樣系統(tǒng),在級(jí)聯(lián)工作模式下可以同時(shí)對(duì)16路信號(hào)進(jìn)行采樣,具有On-Board符合測(cè)量的功能,可以實(shí)現(xiàn)TOF信息的測(cè)量以及能量的測(cè)量。本文通過對(duì)基于LaBr3晶體的TOF-PET定時(shí)校準(zhǔn)系統(tǒng)輸出脈沖進(jìn)行數(shù)字化波形采樣以及數(shù)據(jù)采集,開展了基于DRS4芯片的數(shù)字化波形采樣系統(tǒng)的應(yīng)用以及后續(xù)數(shù)據(jù)處理方法的研究。實(shí)驗(yàn)結(jié)果表明,利用DRS4系統(tǒng)以及數(shù)字化波形分析算法,TOF-PET定時(shí)校準(zhǔn)系統(tǒng)獲得了很好的符合時(shí)間分辨(178 ps)和能量分辨(3.42%@511 keV),優(yōu)于進(jìn)行對(duì)比測(cè)試的CAMAC系統(tǒng)獲得的符合時(shí)間分辨(250ps)以及能量分辨(4.2%@511 keV)。成功研制了由LaBr3晶體陣列、位置靈敏型的光電倍增管及簡化的讀出電路組成的TOF-PET單元樣機(jī)。在國內(nèi)首次利用DRS4系統(tǒng)對(duì)樣機(jī)進(jìn)行了On-Board符合測(cè)試,使用數(shù)字化算法對(duì)采樣數(shù)據(jù)進(jìn)行分析。相比CAMAC系統(tǒng),使用DRS4系統(tǒng)得到的晶體位置映射圖更加清晰且易于分割,信噪比更高。DRS4系統(tǒng)獲得了較好的能量分辨(14.9%)位置分辨(0.74mm)和符合時(shí)間分辨(750 ps),驗(yàn)證了DRS4系統(tǒng)在TOF-PET中應(yīng)用的可行性,實(shí)現(xiàn)了預(yù)期目標(biāo)。我們?cè)趪鴥?nèi)首次利用DRS4系統(tǒng)在原子核能級(jí)壽命測(cè)量以及在束粒子鑒別的實(shí)驗(yàn)中進(jìn)行了應(yīng)用和研究。在原子核能級(jí)壽命測(cè)量實(shí)驗(yàn)中成功利用快定時(shí)法測(cè)量了能級(jí)壽命,獲得的結(jié)果與NNDC發(fā)布的評(píng)估壽命相符合。在束粒子鑒別實(shí)驗(yàn)中對(duì)不同能量的質(zhì)子束,α,12C束以及28Si產(chǎn)生的次級(jí)束粒子進(jìn)行了測(cè)量,可以對(duì)不同的粒子進(jìn)行鑒別。本文對(duì)DRS4數(shù)字化波形采樣系統(tǒng)以及數(shù)字化波形分析算法進(jìn)行了多種應(yīng)用研究。實(shí)驗(yàn)結(jié)果表明DRS4系統(tǒng)以及數(shù)字化波形分析算法在能量和時(shí)間測(cè)量上相比傳統(tǒng)的CAMAC系統(tǒng)具有更高的測(cè)量精度。同時(shí)該系統(tǒng)還具有通道密度高、電路簡單,集成度高、體積小、傳輸噪聲小、成本低、易調(diào)試以及信息集總分析的優(yōu)點(diǎn),滿足了我們對(duì)TOF-PET讀出電子學(xué)的設(shè)計(jì)需求。
[Abstract]:Positron Emission tomography (PET) can monitor the dose distribution and location of heavy ion beam irradiation. The introduction of time of flight time into PET can reduce the data processing time and improve the image quality.In the development of TOF-PET system for heavy ion cancer monitoring, the traditional discrete electronic readout system can not meet the needs of TOF-PET system because of its large scale, complex circuit, high power consumption, low measurement accuracy and poor reliability.Therefore, it is necessary to design and develop a new low-cost, high-integrated readout electronics system.Based on this requirement, we have developed a digital waveform sampling system based on SCA(Switched Capacitor Array-based DRS4 chip Dumino Ring Sampler version 4, which can sample 16 signals simultaneously in cascade mode.It has the function of On-Board conformance measurement, and can realize the measurement of TOF information and energy.In this paper, the output pulse of TOF-PET timing calibration system based on LaBr3 crystal is sampled by digital waveform sampling and data acquisition. The application of digital waveform sampling system based on DRS4 chip and the research of subsequent data processing method are carried out.The experimental results show that,Using DRS4 system and TOF-PET timing calibration system, good coincidence time resolution (178pss) and energy resolution (3.4222r 511keV) are obtained, which is better than that obtained from CAMAC system (250pss) and energy resolution (4.2keV).A TOF-PET cell prototype composed of a LaBr3 crystal array, a position sensitive photomultiplier tube and a simplified readout circuit has been successfully developed.For the first time, the DRS4 system is used to test the On-Board conformance of the prototype in China, and the digital algorithm is used to analyze the sampling data.Compared with CAMAC system, the crystal position map obtained by using DRS4 system is clearer and easier to partition.The higher SNR. DRS4 system obtained better energy resolution (14.9) position resolution (0.74mm) and coincidence time resolution (750psN). The feasibility of the application of DRS4 system in TOF-PET was verified and the expected goal was achieved.We have used DRS4 system for the first time in the measurement of nuclear energy level lifetime and in the experiments of beam particle identification.In the experiment of nuclear energy level life measurement, the fast timing method is successfully used to measure the energy level lifetime. The obtained results are in agreement with the estimated lifetime released by NNDC.In the beam particle identification experiment, the proton beam with different energy, the 偽 ~ (12) C beam and the secondary beam produced by 28Si were measured, which can be used to identify different particles.In this paper, DRS4 digital waveform sampling system and digital waveform analysis algorithm are studied.The experimental results show that the DRS4 system and the digital waveform analysis algorithm have higher measurement accuracy than the traditional CAMAC system in energy and time measurement.At the same time, the system has the advantages of high channel density, simple circuit, high integration, small volume, low transmission noise, low cost, easy debugging and information lumped analysis, which meets the design requirements of TOF-PET readout electronics.
【學(xué)位授予單位】：中國科學(xué)院研究生院(近代物理研究所)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：O571.6

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本文編號(hào)：1699411