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公开(公告)号：US4734579A
公开(公告)日：1988-03-29
申请号：US882508
申请日：1986-07-07
IPC分类号： B01D59/44
CPC分类号： B01D59/44
摘要： An ultrasensitive mass spectrometry method based on multiphoton sub-Doppler resonance ionization to measure abundance sensitivities. The method preferentially ionizes a selected isotope in a sample by using Doppler-free resonant multiphoton ionization to produce an enhanced ratio of selected isotopes. Background species are separately ionized and rejected. As necessary or desired, selected isotope ions are preferentially ionized by using a second Doppler-free resonant multiphoton ionization to provide an additional isotope enhancement. The ions produced are injected into a mass spectrometer. Isotopic spectrum analysis of the ions is performed by the spectrometer and the ions are then detected by a detector such as a particular photon multiplier capable of observing a single ion. In one embodiment, at least one of the steps of preferentially ionizing the selected isotope is accomplished by two counter propagating laser beams of slightly different frequencies. Further improved sensitivity is achieved by: (1) using a frequency offset of the laser frequency in an amount proportional to the laser intensity to overcome AC Stark shifts, and (2) withdrawing ions for mass separation from only the central portion of the laser interaction volume.
摘要翻译： 基于多光子亚多普勒共振电离的超灵敏质谱法测量丰度灵敏度。 该方法优选通过使用无多普勒多谐振多光子电离来选择样品中的所选同位素，以产生所选同位素的增强比例。 背景物种被单独离子化并被拒绝。 根据需要或需要，通过使用第二无多普勒共振多光子电离来提供选择的同位素离子以提供另外的同位素增强。 将产生的离子注入质谱仪中。 离子的同位素谱分析由光谱仪进行，然后通过能够观察单个离子的特定光子倍增器的检测器检测离子。 在一个实施例中，优选电离所选择的同位素的步骤中的至少一个是通过两个频率稍微不同的反向传播激光束实现的。 通过以下方式实现进一步提高的灵敏度：（1）使用与激光强度成比例的量的激光频率的频率偏移来克服AC Stark偏移，和（2）仅从激光相互作用的中心部分取出用于质量分离的离子 卷。
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公开(公告)号：US4634864A
公开(公告)日：1987-01-06
申请号：US546052
申请日：1983-10-27
IPC分类号： B01D59/44
CPC分类号： B01D59/44
摘要： An ultrasensitive mass spectrometry method based on multiphoton sub-Doppler resonance ionization is used to measure abundance sensitivities. The method preferentially ionizes a selected isotope in a sample by using Doppler-free resonant multiphoton ionization to produce an enhanced ratio of selected isotopes. As necessary or desired, selected isotope ions are preferentially ionized by using a second Doppler-free resonant multiphoton ionization to provide an additional isotope enhancement. The ions produced are injected into a mass spectrometer (24). Isotopic spectrum analysis of the ions is performed by the spectrometer (24) and the ions are then detected by a detector (26) such as a particular photon multiplier capable of observing a single ion. In one embodiment, at least one of the steps of preferentially ionizing the selected isotope is accomplished by two counter propagating laser beams of slightly different frequencies.
摘要翻译： 使用基于多光子亚多普勒共振电离的超灵敏质谱方法来测量丰度灵敏度。 该方法优选通过使用无多普勒多谐振多光子电离来选择样品中的所选同位素，以产生所选同位素的增强比例。 根据需要或需要，通过使用第二无多普勒共振多光子电离来提供选择的同位素离子以提供另外的同位素增强。 将产生的离子注入质谱仪（24）。 离子的同位素谱分析由光谱仪（24）进行，然后通过能够观察单个离子的特定光子倍增器的检测器（26）检测离子。 在一个实施例中，优选电离所选择的同位素的步骤中的至少一个是通过两个频率稍微不同的反向传播激光束来实现的。
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公开(公告)号：US4699751A
公开(公告)日：1987-10-13
申请号：US544531
申请日：1983-10-24
摘要： A dosimeter which incorporates new methods for determining neutron dose. Less than one millirad of dose due to neutrons of all energies down to approximately 10.sup.3 eV can be measured, and the response can be adjusted by design of the dosimeter. The dosimeter utilizes the sputtering of material from a target due to the action of the neutrons and measuring of the amount of sputtered material to determine the dose. The sputtered material may be, for example, a noble gas or an inert solid. Various radiator materials can be included to interact with the neutrons so that the resulting charged particles control the sputtering process and hereby increase the sensitivity of the dosimeter. The target material can be, for example, noble-gas-impregnated polycrystalline or amorphous metals. The sputtered material is analyzed using resonance ionization spectroscopy, sputter-initiated resonance ionization spectroscopy or other methods to determine its quantity and hence the neutron dose. Applications include, but are not limited to, personnel neutron dosimetry and stationary neutron monitors.
摘要翻译： 一种剂量计，其包含用于确定中子剂量的新方法。 可以测量由于所有能量的中子降至约103eV的剂量小于1毫升，并且响应可以通过剂量计的设计来调节。 剂量计利用来自靶的材料的溅射，由于中子的作用并且测量溅射的材料的量以确定剂量。 溅射的材料可以是例如惰性气体或惰性固体。 可以包括各种散热器材料以与中子相互作用，使得所得的带电粒子控制溅射工艺，从而增加剂量计的灵敏度。 目标材料可以是例如贵金属气体浸渍的多晶或非晶金属。 使用共振电离光谱法，溅射引发的共振电离光谱法或其他方法分析溅射的材料以确定其量并因此确定中子剂量。 应用包括但不限于人员中子剂量测定法和固定中子监测仪。
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