WO2019029161A1 - 脉冲式电子顺磁共振谱仪 - Google Patents

脉冲式电子顺磁共振谱仪 Download PDF

Info

Publication number
WO2019029161A1
WO2019029161A1 PCT/CN2018/078392 CN2018078392W WO2019029161A1 WO 2019029161 A1 WO2019029161 A1 WO 2019029161A1 CN 2018078392 W CN2018078392 W CN 2018078392W WO 2019029161 A1 WO2019029161 A1 WO 2019029161A1
Authority
WO
WIPO (PCT)
Prior art keywords
microwave
refrigerator
resonant cavity
transmission line
magnet
Prior art date
Application number
PCT/CN2018/078392
Other languages
English (en)
French (fr)
Inventor
周宗权
李佩耘
刘超
刘肖
李传锋
郭光灿
Original Assignee
中国科学技术大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 中国科学技术大学 filed Critical 中国科学技术大学
Priority to US16/331,457 priority Critical patent/US10802102B2/en
Priority to DE112018000097.4T priority patent/DE112018000097T5/de
Priority to GB1902245.8A priority patent/GB2567397B/en
Priority to JP2019509501A priority patent/JP2020504286A/ja
Publication of WO2019029161A1 publication Critical patent/WO2019029161A1/zh

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/60—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using electron paramagnetic resonance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/30—Sample handling arrangements, e.g. sample cells, spinning mechanisms
    • G01R33/31—Temperature control thereof

Definitions

  • the present disclosure relates to the field of magnetic resonance spectrometers, and more particularly to a pulsed electron paramagnetic resonance spectrometer that can operate at ultra-low temperatures.
  • EPR is a highly sensitive, non-invasive detection method with a wide range of applications in physical, chemical, biological, medical, and engineering fields. Some typical uses include engineering and safety applications for material impurities, or defect detection, chemical reactions for specific elemental quantitative analysis, biological imaging for tissue imaging, medical fields for quantitative analysis of radiation doses, and condensed states. It is used in physics for multi-body correlation, phase change problems, and functions in the field of quantum information for quantum computing and quantum storage.
  • the standard EPR system mainly includes the following modules: microwave source, microwave pulse modulation and demodulation module, microwave amplifier, microwave bridge, sample rod, three-dimensional microwave resonant cavity, super-uniform magnet.
  • microwave source microwave pulse modulation and demodulation module
  • microwave amplifier microwave bridge
  • sample rod three-dimensional microwave resonant cavity
  • super-uniform magnet When the incident microwave of the EPR system is a continuous wave, this continuous wave EPR system can only be used for transition resonance signal detection.
  • the incident microwave of the EPR system can also be set as a complex microwave pulse train.
  • This pulsed EPR system can be more abundant and can be used for other spin dynamics analysis such as spin population life and coherence life.
  • the prior art often requires a pulsed EPR system to realize spin quantum state manipulation, controlled quantum logic gate, microwave quantum state storage and the like.
  • an object of the present disclosure to provide an electron paramagnetic resonance spectrometer having a sample temperature on the order of 0.1 K and having various test functions of a conventional electron paramagnetic resonance spectrometer.
  • the present disclosure provides a pulsed electron paramagnetic resonance spectrometer comprising:
  • a microwave excitation generating unit that generates at least one microwave pulse
  • a microwave conducting unit comprising a resonant cavity and a microwave transmission line for transmitting microwaves, the microwave transmission line being connected between the microwave excitation generating unit and the resonant cavity, wherein the resonant cavity is configured to place a sample;
  • a refrigerator and a magnet unit comprising a refrigerator that achieves a 0.1 Kelvin ultra-low temperature cooling of the microwave cavity, the resonant cavity being disposed in the refrigerator, the microwave transmission line being disposed to penetrate the refrigerator and connected to the refrigerator
  • the resonant cavity; the chiller and the magnet unit further includes a magnet that provides a magnetic field for the magnetic resonance test of the sample, the resonant cavity being disposed in a room temperature gap of the magnet.
  • the microwave conducting unit comprises a sample plunger having one end mounted with the resonant cavity and the other end secured to the refrigerator.
  • the refrigerator includes a plurality of cold plates disposed along a direction of passage of the microwave transmission line to cool the microwave transmission lines step by step.
  • the microwave cavity is a microwave cavity comprising a plurality of L, S, X operating bands and electron and nuclear double resonance.
  • the conductive medium of the microwave transmission line is silver plated stainless steel, silver plated CuNi, and NbTi superconductor.
  • the refrigerator and magnet unit further comprise:
  • An electric rail for carrying and positioning the magnet An electric rail for carrying and positioning the magnet.
  • the refrigerator end is cylindrical and the outer diameter is compatible with the magnet gap, the refrigerator tail inner diameter being compatible with the resonant cavity.
  • the microwave transmission line mounts heat sinks and adapters at each of the cold plates to sufficiently cool the outer casing and inner core of the microwave transmission line cable.
  • the sample plunger comprises a thermally conductive metallic material.
  • a thermal radiation shield can be mounted outside the cold plate of each stage.
  • the EPR system can be combined with the setting mode of the refrigerator and the microwave transmission line to obtain a sample temperature of the order of 0.1 K, thereby realizing EPR detection in the ultra-low temperature zone.
  • the electric rail can conveniently realize the docking and assembly operation of the EPR system and the refrigeration system; the equipment used in the above process is easy to operate and has high stability, and the sample temperature is low and compatible with all functions of the conventional EPR system.
  • FIG. 1 is a block diagram of a pulsed electron paramagnetic resonance spectrometer according to an embodiment of the present disclosure
  • FIG. 2 is a schematic partial assembly diagram of a pulsed electron paramagnetic resonance spectrometer according to an embodiment of the present disclosure
  • FIG. 3 is a schematic diagram of a field electron spin echo (ESE) of Nd 3+ ions in a YSO crystal at a temperature of 6.5 K using the resonance spectrometer shown in FIG. 2 according to an embodiment of the present disclosure;
  • ESE field electron spin echo
  • FIG. 4A and FIG. 4B are diagrams showing electron spin echo (ESE) versus temperature dependence of Nd 3+ ions in the YSO crystal under the ultra-low temperature region using the resonance spectrometer shown in FIG. 2 according to an embodiment of the present disclosure.
  • 4A shows the time domain signal of the measured electron spin echo at different sample temperatures;
  • FIG. 4B shows the relationship between the relative magnitude of the electron spin echo and the sample temperature.
  • Ultra-low temperature refers to a temperature on the order of 0.1 K (Kelvin).
  • the EPR spectrometer in the ultra-low temperature zone is a major basic instrument urgently needed in the field of quantum information and quantum storage.
  • the population of electron spins in the X-band EPR spectrometer can achieve an initialization level of more than 95%, which directly makes the signal-to-noise ratio of the electron spin echo (that is, the signal-to-noise ratio of the instrument).
  • One to two orders of magnitude are enhanced compared to the 3K temperature test conditions.
  • the improvement of signal-to-noise ratio is the fundamental indicator of all measuring instruments, so the ultra-low temperature EPR system is expected to find more applications in other fields.
  • a pulsed electron paramagnetic resonance spectrometer comprising:
  • the microwave conducting unit includes a resonant cavity and a microwave transmission line for transmitting microwaves, the microwave transmission line is connected between the microwave excitation generating unit and the resonant cavity, and the resonant cavity is configured to be placed a chiller and a magnet unit, comprising a chiller for achieving ultra-low temperature cooling of the microwave cavity, the microwave transmission line being disposed to pass through the chiller and connecting the microwave cavity; the chiller and the magnet unit further comprising providing The sample magnetic resonance test magnet of the magnetic field, the resonant cavity being disposed in a room temperature gap of the magnet. It may also include a microwave detecting unit that collects and analyzes the microwave conducting unit to emit microwaves. With the above arrangement, the EPR system can be combined with a refrigerator to obtain an ultra-low sample temperature of the order of 0.1K.
  • FIG. 1 is a schematic diagram of a system framework according to Embodiment 1 of the present disclosure. As shown in Figure 1, the device mainly includes:
  • the microwave excitation generating unit 11 is configured to generate various high-energy microwave pulses
  • the microwave conducting unit 12 is configured for directional transmission of microwave pulses, mounting samples and realizing microwave emission and collection;
  • the microwave detecting unit 13 is configured to collect and analyze microwave signals
  • the microwave excitation generating unit 11, the microwave conducting unit 12 and the microwave detecting unit 13 are provided with complete test functions such as sweeping paramagnetic resonance detection, electron spin echo, electron and nuclear double resonance.
  • the refrigerator and the magnet unit 14 are configured to achieve ultra-low temperature cooling of the microwave cavity and provide a high uniformity magnetic field to achieve magnetic resonance test conditions.
  • the microwave excitation generating unit 11 includes: a microwave source 111, a microwave modulation module 112, a microwave frequency conversion module 113, and a microwave amplifier 114;
  • the microwave source 111 is configured to generate a single-frequency microwave signal of a specific frequency
  • the microwave modulation module 112 is configured to generate microwave pulses of various sizes, phases, and frequencies from a single-frequency continuous microwave;
  • the microwave frequency conversion module 113 is configured to extend a test frequency band of the microwave
  • the microwave amplifier 114 is configured to perform amplification on the microwave pulses to achieve the high energy pulses required for the pulsed EPR.
  • the microwave conducting unit 12 includes: a microwave circulator 121, a microwave transmission line 122, and a microwave resonant cavity 123;
  • the microwave circulator 121 is used for directional transmission of microwaves, guiding microwaves of the microwave excitation unit 11 into the sample, and transmitting sample signals into the microwave detecting unit 13;
  • the microwave transmission line 122 is used for microwave conduction between the microwave circulator 121 and the microwave cavity 123; unlike the conventional microwave transmission cable, considering the ultra-low temperature cooling requirement of the device, the material selection of the microwave transmission line should be balanced.
  • typical conductive media can be silver plated stainless steel, silver plated CuNi, and NbTi superconductors.
  • the microwave resonant cavity 123 is used for mounting a sample and realizing the emission and collection of microwaves.
  • the microwave resonant cavity 123 of the present disclosure is a three-dimensional resonant cavity, and the three-dimensional resonant cavity generates an alternating magnetic field distribution and can test large-sized samples with more Rich testing capabilities.
  • the orbital microwave detecting unit 13 includes: a protection gate 131, a mixer 132, a low pass filter and amplifier 133, and an oscilloscope 134;
  • the protection gate 131 is configured to turn off the detection system when the high-energy microwave pulse is incident; when the signal is detected, the detection system is turned on;
  • the mixer 132 is configured to extract the microwave signal collected by the microwave conduction module and the local oscillator microwave; the local oscillator microwave is from the microwave excitation generating unit 11
  • the low-pass filter and amplifier 133 is configured to perform low-pass filtering and amplification on the mixed signal output by the mixer 132 to implement pulse demodulation; and for amplifying the demodulated pulse signal;
  • the oscilloscope 134 is used for storing and displaying signals.
  • the refrigerator unit 14 includes: a refrigerator 141, a refrigerator cavity 142 and a super-uniform magnet 143, an electric rail 144;
  • the refrigerator 141 is configured to provide a cooling capacity and cool the target system; the temperature of the sample of the instrument can reach 0.1K by the refrigerator;
  • the refrigerator cavity 142 is used for mounting the microwave transmission line 122 and the microwave resonant cavity 123, and isolating external heat radiation;
  • the super-uniform magnet 143 is used to generate a high-uniformity and high-stability magnetic field; it may be a room temperature electromagnet or a superconducting magnet.
  • the electric rail 144 is used for carrying and positioning the magnet when performing sample exchange; the electric rail has a jack that is operated up and down for carrying and positioning the magnet, and the horizontal stroke exceeds the outer dimension of the magnet.
  • the embodiment of the present disclosure combines a refrigerator and a conventional EPR system to realize an ultra-low temperature EPR test and contributes to a significant improvement in the signal-to-noise ratio of the test; the apparatus used in the above process is easy to operate, and the system has high stability. And perfect testing capabilities.
  • FIG. 1 can be purchased and assembled separately, or a multi-module assembled subsystem can be provided from the prior art, and a pulsed electron paramagnetic resonance spectrometer can be easily constructed based on such a subsystem.
  • a commercial EPR spectrometer can provide a microwave excitation unit, a circulator in the microwave conduction unit, a microwave cavity, a microwave detection unit, and a super-uniform magnet in the refrigerator and the magnet unit.
  • FIG. 2 is a schematic diagram of system assembly of an EPR spectrometer according to an embodiment of the present disclosure.
  • the multi-layer radiation shield in the low temperature chamber and the matching compressor unit in the low temperature chamber are omitted in the figure, which only shows the important details of the system docking.
  • Pulsed multi-band EPR system (here the EPR system includes a microwave excitation generating unit, a microwave circulator in the microwave conducting unit, a microwave resonant cavity, a microwave detecting unit, and a magnet in the refrigerator and the magnet unit)
  • L/S/X band microwave bridge L/S/X band microwave amplifier
  • microwave modulator based on arbitrary waveform generator
  • L/S/X band microwave cavity L/S/X band microwave cavity
  • X-band microwave detection system electronics and Nuclear double resonance (ENDOR) module and super-uniform magnet.
  • ENDOR Nuclear double resonance
  • the parameters of the X-band microwave bridge may be: a frequency range of 9.0 to 10.0 GHz.
  • the L/S band microwave bridge mainly realizes the function of frequency conversion. It is based on the mixer with fixed local oscillator frequency to realize the signal frequency conversion of X-band and L/S bands. This type of frequency conversion achieves frequency band expansion and is the most economical way. Multiple bands can share the X-band microwave detection module. Microwave circulators are built into the microwave bridges of the three bands to realize directional transmission of microwaves.
  • the X-band microwave amplifier is a 300W solid-state amplifier, and the output power of the L/S-band amplifier is about 100W.
  • the parameters of the microwave modulator based on the arbitrary waveform generator may be: a sampling rate of 5 GS/s, a modulation bandwidth of 500 MHz, and arbitrary waveform modulation for frequency, phase, and amplitude.
  • the L/S/X-band microwave cavity parameter can be: the effective aperture of the internal cavity of each band is 5 mm, the outer diameter is 20 mm, and the SMB or MMCX type quick connector is used to realize convenient band replacement.
  • the Q value of each band resonator can be about 50 to 500, and the required Q value is determined according to a specific experiment.
  • the parameters of the coil type super-uniform superconducting magnet may be: magnetic field uniformity of 10 ppm @ 40 mm DSV, maximum field strength of 1.8 T, and air gap of 100 mm.
  • the parameters of the refrigerator may be: a dilution refrigerator without liquid helium consumption, the lowest temperature is 10 mK, the cooling power is 400 uW at 100 mK, and the cooling power is 1 W at 4K.
  • the preferred refrigerator cavity 201 parameters may include: 50K cold plate 2055, 3K cold plate 2054, 1K cold plate 2053, 100mK cold plate 2052, and 10mK cold plate 2051.
  • 50K cold plate 2055, 3K cold plate 2054, 1K cold plate 2053 are required to be equipped with a heat radiation shielding cover (not shown).
  • the outer diameter of the tail of the refrigerator is 95mm, and the effective inner diameter of the tail sample space is 40mm.
  • the refrigeration system is inserted into the magnet air gap of the electron paramagnetic resonance system from above. .
  • the resonant cavity 203 is mounted on a sample rod 207 of a thermally conductive metal material, and the other end of the sample plunger 207 is fixed to the lowest temperature cold plate 2051 of 10 mK, and other cold plates (2052, 2053, 2054, and 2055). There is no connection between them.
  • the parameters of the microwave transmission line may be: a semi-rigid coaxial transmission line, and the outer diameter of the wire may be 3.5 mm; the outer casing and the inner core of the wire may be silver-plated stainless steel, superconducting materials, etc., which are not easily conductive and conductive. .
  • a plurality of heat sinks 206 are disposed on the lines of the microwave transmission line 208.
  • the parameters of the electric rail 204 may be: a load capacity of more than 3 tons, a working stroke of 1.5 meters, and a positioning accuracy of 0.1 mm.
  • the size of the rail working panel is 550mm*550mm.
  • the height of the legs on both sides may be 230 mm, and the distance between the legs on both sides is 600 mm.
  • the guide rail is equipped with a 20mm height stroke jack for supporting or positioning and then lowering the magnet. After the rail jack is raised, the working panel is 240 mm away from the total height of the ground. At this time, the rail working panel directly supports the magnet 202 and carries the positioning. After the rail jack is dropped, the magnet 202 is separated from the rail surface and directly supported on the ground.
  • the tail end of the refrigerator is cylindrical, the outer diameter is compatible with the gap of the magnet, and the inner diameter of the tail end of the refrigerator is compatible with the resonant cavity.
  • thermometer and the auxiliary spin polarization calibration method may be used to measure the actual operating temperature of the system and the sample.
  • the spin-polarization level of the rare earth ions can be used to accurately determine the actual working temperature of the sample.
  • the X-band ENDOR resonator is installed in the system.
  • the cavity is filled with 20ppm 143 Nd isotope-doped YSO crystal.
  • the crystal also contains about 1ppm of even mass isotope (including 142 Nd, 164 Nd, 148 Nd).
  • the external test magnetic field is parallel to the D1 axis of the crystal.
  • Figure 3 shows the test results of the sweep electron spin echo at 6.5K, which includes 16 lines of 143 Nd and two lines of even mass Nd isotope.
  • Figure 4A shows the spin echo signals obtained when changing the different cold plate temperatures under the 4581G magnetic field.
  • the magnetic resonance signals acquired under the test magnetic field are derived from even-numbered Nd isotopes.
  • the experimental evolution of spin was 2us, which is much lower than the electron spin coherence lifetime (20us ⁇ 200us) at all test temperatures.
  • the even-mass Nd isotope has an electron spin of 1/2 and a nuclear spin of zero, which is a simple two-level system under magnetic field.
  • the relative magnitude of the spin echo is proportional to the difference in the population of the target transition. According to the Boltzmann distribution, the difference in the two-level population at different temperatures can be strictly calculated:
  • h is the Planck constant
  • h*v is the energy of the resonant microwave photon
  • k is the Boltzmann constant
  • T is the sample temperature.
  • Figure 4B shows that as the cold disk temperature drops, the sample echo signal increases gradually.
  • the signal-to-noise ratio can be increased by more than 20 times compared to a commercial instrument with a 4.5K operating temperature at 0.1K operating temperature.
  • the experimental results are in full compliance with the spin polarization levels predicted by the Boltzmann distribution, so it is rigorously proven that the sample operating temperature reaches 0.1K.
  • an original pulsed electron paramagnetic resonance spectrometer is developed, and the thermometer shows that the sample chamber has a no-load temperature of less than 10 mK.
  • the ultra-low temperature spin echo test of Nd 3+ ions in YSO crystal is completed. According to the size of the spin echo signal, the actual working temperature of the sample can reach 0.1K.
  • This is the three-dimensional cavity pulsed electron paramagnetic resonance spectrometer that reports the lowest temperature in the world. Its various components are general-purpose electrical devices, and the device is stable and fully functional, and has broad application prospects.

Landscapes

  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)

Abstract

一种脉冲式电子顺磁共振谱仪，包括：产生至少一种微波脉冲的微波激励产生单元(11)；微波传导单元(12)，包括微波谐振腔(123)和传输微波的微波传输线(122)，微波传输线(122)连接于微波激励产生单元(11)和微波谐振腔(123)之间，微波谐振腔(123)配置为置放样品；制冷机及磁体单元(14)，包括对微波谐振腔(123)实现超低温冷却的制冷机(141)，微波传输线(122)设置为穿过制冷机(141)并连接微波谐振腔(123)；制冷机及磁体单元(14)还包括提供达到样品磁共振测试磁场的磁体(143)，微波谐振腔(123)设置于磁体(143)的室温间隙中。本装置可获得0.1开尔文量级的超低样品温度，并且仪器功能齐全，易于操作。

Description

脉冲式电子顺磁共振谱仪 技术领域
本公开涉及磁共振谱仪领域，尤其涉及一种可以在超低温度下工作的脉冲式电子顺磁共振谱仪。
背景技术
电子顺磁共振谱仪(electron paramagnetic resonance,EPR)是一种研究物质内未配对电子的装置。它的基本原理是为配对电子自旋的塞曼效应：单个电子具有s＝1/2的自旋量子数，故可以处于m s＝+1/2或m s＝-1/2的自旋量子态，当存在外磁场时，这两种自旋状态的能量将产生劈裂。进一步施加微波场探测该能级劈裂的共振信号，即可获取物质系统的内部信息，包括电子周围的核种类、磁场环境、电子自旋间距等等。
EPR是一种高灵敏度、非侵入式的检测方法，在物理、化学、生物、医学、工程等多种领域具有广泛的应用。一些典型的用途包括，工程及安全领域用于材料的杂质、或缺陷检测、化学反应中用于特定元素定量分析、生物领域中用于组织成像、医学领域用于辐射剂量的定量分析、凝聚态物理中用于多体关联、相变问题的研究以及量子信息领域中用于实现量子计算和量子存储等功能。
标准EPR系统主要包括以下模块：微波源、微波脉冲调制及解调模块、微波放大器、微波桥、样品杆、三维微波谐振腔、超均匀磁体。当EPR系统的入射微波为连续波时，这种连续波EPR系统只能用于跃迁谐振信号探测。EPR系统的入射微波也可以设置为复杂微波脉冲序列，这种脉冲式EPR系统功能能更为丰富，可用于自旋布居数寿命以及相干寿命等其它自旋动力学分析。以量子信息领域的应用为例，现有技术往往一般需要脉冲式EPR系统，从而实现自旋量子态操控、受控量子逻辑门、微波量子态存储等等功能。
目前国际上能够生产脉冲式EPR系统的厂家主要有德国的 BRUKER公司。考虑固体材料的EPR分析，为了冷却物质内部电子-声子相互作用，一般都需要低温环境。目前商用EPR系统能够到达的最低样品温度约为3K。但这个温度无法满足量子信息领域对固体长相干寿命的需求。举一个典型的例子，近年来稀土离子掺杂晶体实现了对单个光子量子态的高保真度存储，是具有实用化潜力的量子存储系统。它的存储寿命最终限制是离子的电子自旋以及核自旋的相干寿命。一种现有技术的脉冲式EPR系统，对其分析结果显示随着温度的下降，样品电子自旋以及核自旋相干寿命均随着温度下降，显著上升。当到达该系统最低温度5K时，样品电子自旋核核自旋相干寿命分别达到0.1ms和1ms量级[Phys.Rev.Lett.114.170503(2015)]。然而实用化的量子存储器一般需要秒量级的存储寿命。继续降低该实验中的样品温度显然可以获得更长的相干寿命，然而该研究组没有办法做进一步的数据，原因就是目前所有商用EPR系统无法到达3K以下温区。国际学术界甚至存在一种普遍的看法，认为三维谐振器的EPR系统不可能到达3K以下样品温度。比如文献[Appl.Phys.Lett.106.193505(2015)]在第一页第二段中明确指出了这一点。如果采用传输线型的谐振腔则容易实现降温，但这种谐振腔产生的交流磁场只分布在传输线附近几十至几百微米量级的尺度范围，该磁场随着距离变化剧烈衰减，其缺点是样品尺度受限并且磁场均匀度很差。
发明内容
有鉴于此，本公开的目的是在于提供一种电子顺磁共振谱仪，其样品温度达0.1K量级并且具备常规电子顺磁共振谱仪的各种测试功能。
本公开提供一种脉冲式电子顺磁共振谱仪，包括：
产生至少一种微波脉冲的微波激励产生单元；
微波传导单元，包括谐振腔和传输微波的微波传输线，所述微波传输线连接于微波激励产生单元和谐振腔之间，所述谐振腔配置为置放样品；
制冷机及磁体单元，包括对微波谐振腔实现0.1开尔文量级超低温冷却的制冷机，所述谐振腔设置于所述制冷机内，所微波传输线设置为穿入所述制冷机并连接至所述谐振腔；制冷机及磁体单元还包括提供达到所述样品磁共振测试磁场的磁体，所述谐振腔设置于磁体的室温间隙中。
在进一步的实施方案中，所述微波传导单元包括样品插杆，所述样品插杆一端安装有所述谐振腔，另一端与所述制冷机固定。
在进一步的实施方案中，所述制冷机包括沿微波传输线穿过方向设置的多层冷盘，以逐级冷却微波传输线。
在进一步的实施方案中，所述微波谐振腔为包括L,S,X多种工作波段以及电子与核双共振的微波谐振腔。
在进一步的实施方案中，所述微波传输线的导电介质为镀银不锈钢、镀银CuNi以及NbTi超导体。
在进一步的实施方案中，所述制冷机及磁体单元还包括：
电动导轨，所述导轨用于搬运和定位所述磁体。
在进一步的实施方案中，所述制冷机尾端为圆柱形，外径兼容所述磁体间隙，所述制冷机尾端内径兼容所述谐振腔。
在进一步的实施方案中，所述微波传输线在各级冷盘处安装热沉及转接头以充分冷却微波传输线线缆的外壳及内芯。
在进一步的实施方案中，所述样品插杆包含导热金属材料。
在进一步的实施方案中，各级所述冷盘外安装有热辐射屏蔽罩壳。
由上述本公开提供的技术方案可以看出，将EPR系统配合制冷机和微波传输线的设置方式，可以获得0.1K量级的样品温度，从而实现超低温区的EPR检测。利用电动导轨可以方便地实现EPR系统与制冷系统的对接及组装运行；该上述过程所采用的设备易于操作且稳定性高，其样品的温度低且兼容常规EPR系统的所有功能。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本公开的一些实施例，对于本领域的普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他附图。
图1为本公开实施例提供的脉冲式电子顺磁共振谱仪框架图；
图2为本公开实施例提供的脉冲式电子顺磁共振谱仪局部组装示意图；
图3为本公开实施例提供的应用图2所示共振谱仪在6.5K温度下YSO晶体中Nd 3+离子的扫场电子自旋回波(ESE)示意图；
图4A和图4B为本公开实施例提供的应用图2所示共振谱仪在超低温区下YSO晶体中Nd 3+离子的电子自旋回波(ESE)与温度依赖关系图。其中，图4A给出不同样品温度下实测电子自旋回波的时间域信号；图4B给出电子自旋回波的相对大小与样品温度的关系。
具体实施方式
下面结合本公开实施例中的附图，对本公开实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本公开一部分实施例，而不是全部的实施例。基于本公开的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本公开的保护范围。
本公开所述的“超低温”是指0.1K(开尔文)量级的温度。
如上所述，超低温区的EPR谱仪是量子信息、量子存储领域急需的重大基础仪器。例如考虑0.1K的超低温下，X波段EPR谱仪中电子自旋的布居数可以实现95％以上的初始化水平，这直接使得电子自旋回波的信噪比(也就是仪器的信噪比)相比3K温度的测试条件，增强一到两个量级。信噪比的提升是一切测量仪器的根本指标，故超低温EPR系统也有望在其他领域取得更多的应用。
根据本公开的基本构思，提供一种脉冲式电子顺磁共振谱仪，包括：
产生至少一种微波脉冲的微波激励产生单元；微波传导单元，包括谐振腔和传输微波的微波传输线，所述微波传输线连接于微波激励产生单元和谐振腔之间，所述谐振腔配置为置放样品；制冷机及磁体单元，包括对微波谐振腔实现超低温冷却的制冷机，所微波传输线设置为穿过所述制冷机并连接所述微波谐振腔；制冷机及磁体单元还包括提供达到所述样品磁共振测试磁场的磁体，所述谐振腔设置于磁体的室温间隙中。还可以包括采集以及分析微波传导单元发射微波的微波探测单元。通过上述设置，将EPR系统配合制冷机，可以获得0.1K量级的超低样品温度。
图1为本公开实施例一提供的系统框架的示意图。如图1所示，该装置主要包括：
微波激励产生单元11，微波传导单元12，微波探测单元13以及制冷机及磁体单元14。
其中，所述微波激励产生单元11，用于产生各种高能微波脉冲；
所述微波传导单元12，用于微波脉冲的定向传输，安装样品并实现微波的发射及收集；
所述微波探测单元13，用于微波信号的采集以及分析；
所述微波激励产生单元11，微波传导单元12及微波探测单元13具备扫场顺磁共振检测、电子自旋回波、电子与核双共振等完备测试功能。
所述制冷机及磁体单元14，用于对微波谐振腔实现超低温冷却并提供高均匀度的磁场，达到磁共振测试条件。
进一步的，所述微波激励产生单元11包括：微波源111、微波调制模块112，微波变频模块113、微波放大器114；
其中，所述微波源111，用于产生特定频率的单频微波信号；
所述微波调制模块112，用于从单频连续微波产生各种大小、相位、频率的微波脉冲；
所述微波变频模块113，用于扩展微波的测试频段；
所述微波放大器114，用于对微波脉冲执行放大，达到脉冲EPR所 需要的高能量脉冲。
进一步的，所述微波传导单元12包括：微波环形器121、微波传输线122以及微波谐振腔123；
其中，所述微波环形器121，用于微波的定向传输，引导微波激励单元11的微波进入样品，并传输样品信号进入微波探测单元13；
所述微波传输线122，用于在微波环形器121以及微波谐振腔123之间的微波传导；与常规微波传输线缆不同，考虑到本装置的超低温冷却需求，所述微波传输线的材质选择应兼顾导电及隔热需求，典型的导电介质可以是镀银不锈钢、镀银CuNi以及NbTi超导体。
所述微波谐振腔123，用于安装样品并实现微波的发射及收集；本公开的微波谐振腔123为三维谐振腔，该三维谐振腔产生的交流磁场分布均匀且可以测试大尺寸样品，具备更丰富的测试功能。
进一步的，所述轨道微波探测单元13包括：保护门131,混频器132、低通滤波及放大器133及示波器134；
其中，所述保护门131，用于在高能微波脉冲入射时，关闭探测系统；信号探测时，打开探测系统；
所述混频器132，用于对微波传导模块收集到的微波信号与本振微波混频提取信号；其本振微波来自微波激励产生单元11
所述低通滤波及放大器133，用于将混频器132输出的混频信号执行低通滤波及放大，实现脉冲解调；用于对解调后脉冲信号的放大；
所述示波器134，用于对信号的存储及显示。
进一步的，所述制冷机单元14包括：制冷机141,制冷机腔体142以及超均匀磁体143,电动导轨144；
其中，所述制冷机141，用于提供制冷量，冷却目标系统；通过该制冷机所述仪器的样品温度可以到达0.1K量级；
所述制冷机腔体142，用于微波传输线122以及微波谐振腔123的安装，并隔离外界热辐射；
所述超均匀磁体143，用于产生高均匀度高稳定的磁场；可以是室温电磁铁或者是超导磁体。
所述电动导轨144，在执行样品更换时，用于对磁体的搬运及定位；所述电动导轨具备上下运行的千斤顶用于搬运及定位放置磁体，且水平方向行程超过磁体外形尺寸。
本公开实施例将制冷机和常规EPR系统结合起来，实现了超低温的EPR测试，并有助于显著提高测试的信噪比；该上述过程所采用的设备易于操作，系统具有较高的稳定性及完善的测试功能。
为了进一步介绍本公开，本公开实施例将列举具体的数值，对该装置中的元件参数进行介绍；需要说明的是，所列举的元件参数数值仅为便于理解本公开，并非构成限制；在实际应用中，用户可以根据需求或经验采用不同参数的元件。
图1中的各部分模块既可以单独购置并组装，也可以从现有技术中提供多模块组装后的子系统，基于这样的子系统更容易搭建出脉冲式电子顺磁共振谱仪。比如商用EPR谱仪可以提供微波激励单元、微波传导单元中的环形器及微波腔、微波探测单元以及制冷机及磁体单元中的超均匀磁体。如图2所示，为本公开实施例提供的一种EPR谱仪的系统组装示意图。图中省略了低温腔内的多层防辐射罩壳及低温腔的配套压缩机组等，仅展现了系统对接的重要细节。
其主要包括：
1)脉冲式多波段EPR系统(此处的EPR系统包含了微波激励产生单元、微波传导单元中的微波环形器以及微波谐振腔、微波探测单元，和制冷机与磁体单元中的磁体)
它主要包括：L/S/X波段微波桥，L/S/X波段微波放大器，基于任意波形发生器的微波调制器，L/S/X波段微波谐振腔，X波段微波检测系统，电子与核双共振(ENDOR)模块以及超均匀磁体。
本实施例中，X波段微波桥的参数可以为：频率范围9.0～10.0GHz。L/S波段的微波桥主要实现频率变换的功能,它基于固定本振频率的混频器实现X波段与L/S两种波段信号频率变换。这种变频的方式实现频段扩展，是最经济的一种方式，多种波段可以共用X波段的微波探测模块。三种波段的微波桥都内置了微波环形器，实现微波的定向传输。
本实施例中，X波段微波放大器是300W的固体放大器，L/S波段放大器的输出功率约100W。
本实施例中，基于任意波形发生器的微波调制器的参数可以为：采样率5GS/s，调制带宽500MHz，对频率、相位、幅度实现任意波形调制。
本实施例中，L/S/X波段微波谐振腔参数可以为：各波段谐振腔内部有效孔径5mm，外径20mm，采用SMB或MMCX型快接头，实现方便地波段更换。各波段谐振腔的Q值可以是50到500左右，根据具体实验决定所需要的Q值。
本实施例中，线圈型超均匀超导磁体的参数可以为：磁场均匀度10ppm@40mm DSV，最大场强1.8T，空气间隙100mm。
2)稀释制冷机系统(由于该部分作为本公开实施例的主要改进点，因此，单独列举进行说明，其对应图1中的制冷机)
本实施例中，制冷机的参数可以为：无液氦消耗的稀释制冷机，最低温度10mK，100mK下制冷功率400uW，4K下制冷功率1W。
本实施例中，优选的制冷机腔体201参数可以为：包含50K冷盘2055，3K冷盘2054,1K冷盘2053，100mK冷盘2052以及10mK冷盘2051。其中50K冷盘2055，3K冷盘2054,1K冷盘2053均需配套安装热辐射屏蔽罩壳(图中未示出)。制冷机尾部外径95mm，尾部样品空间有效内径40mm。
所述制冷系统由上方插入电子顺磁共振系统的磁体空气间隙中。。
3)特制的系统衔接件
其主要包括样品插杆207、微波传输线208。
本实施例中，谐振腔203安装在一个导热金属材质的样品插杆207上，样品插杆207的另一端固定于10mK的最低温冷盘2051上，与其他冷盘(2052、2053、2054和2055)之间无连接。本实施例中，微波传输线的参数可以为：半刚性的同轴传输线，线外径可以为3.5mm；线的外壳及内芯可以是镀银不锈钢、超导材料等不易导热且易导电的材质。
为进一步提高冷却效果，在微波传输线208的线路上设置多个热沉 206。
4)电动导轨204
本实施例中，电动导轨204的参数可以为：负重能力大于3吨，工作行程1.5米，定位精度0.1mm。导轨工作面板的大小为550mm*550mm。
本实施例中的磁体202，其两侧垫脚高度可以为230mm，两侧垫脚距离为600mm。导轨配备20mm高度行程的千斤顶，用于支撑起或定位后放下磁体。导轨千斤顶升起后，工作面板距离地面总高度240mm，此时导轨工作面板直接支撑起磁体202并搬运定位。导轨千斤顶落下后，磁体202脱离导轨面，直接支撑在地面上。
图中，制冷机尾端为圆柱形，外径兼容所述磁体间隙，制冷机尾端内径兼容所述谐振腔。
本实施例中，为了优化系统降温过程、衡量实际系统的温度表现，可以采用温度计测量辅助自旋极化标定的手段测定系统及样品实际工作温度。
系统安装S波段微波谐振腔时，在谐振腔内安装了一个标定过的RuO 2电阻温度计，随着温度降低，电阻值逐步升高。结果显示，谐振腔无实际测试样品的条件下，最低温度达10mK以下。
进一步的，本实施例中可采用稀土离子自旋极化水平准确测定样品实际工作温度。系统安装了X波段ENDOR谐振腔，腔内装载了20ppm浓度 143Nd同位素掺杂的YSO晶体，晶体中还含有1ppm左右的偶数质量数的同位素(包括 142Nd， 164Nd， 148Nd)。外部测试磁场与晶体的D1轴平行。图3给出了6.5K温度下，扫场电子自旋回波的测试结果，它包括16条 143Nd的谱线和2条偶数质量数Nd同位素的谱线。
图4A给出了在4581G磁场下，改变不同的冷盘温度时，获得的自旋回波信号。该测试磁场下获取的磁共振信号来自于偶数质量数的Nd同位素。实验选取自旋演化时长为2us，远低于所有测试温度下的电子自旋相干寿命(20us～200us)。
偶数质量数的Nd同位素的电子自旋为1/2，核自旋为零，在磁场下是简单的二能级系统。其自旋回波相对大小正比于目标跃迁的布居数差， 根据玻尔兹曼分布可以严格计算不同温度下的二能级布居数差:
Figure PCTCN2018078392-appb-000001
其中h为普朗克常数，v＝9.56GHz为微波频率，h*v为共振微波光子的能量，k为玻尔兹曼常数，T为样品温度。当T逼近绝对零度0K时，自旋回波大小达到相对最大值1。
图4B可以看到随着冷盘温度下降，样品回波信号逐步增加，设备在0.1K工作温度下相比4.5K工作温度的商业化仪器，信噪比可提升超过20倍。实验结果完全符合玻尔兹曼分布所预测的自旋极化水平，故严格证明了样品工作温度到达0.1K。
本公开实施例中研制了独创的脉冲式电子顺磁共振谱仪，温度计显示样品腔无负载温度达到10mK以下。基于该装置完成了YSO晶体中Nd 3+离子的超低温自旋回波测试，根据自旋回波信号的大小标定出样品实际工作温度可以到达0.1K。这是国际上报道最低温度的三维谐振腔脉冲式电子顺磁共振谱仪。它的各部分元器件都是通用型的电学器件，装置稳定且功能齐全，具有广泛应用前景。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，仅以上述各功能模块的划分进行举例说明，实际应用中，可以根据需要而将上述功能分配由不同的功能模块完成，即将装置的内部结构划分成不同的功能模块，以完成以上描述的全部或者部分功能。
以上所述的具体实施例，对本公开的目的、技术方案和有益效果进行了进一步详细说明，应理解的是，以上所述仅为本公开的具体实施例而已，并不用于限制本公开，凡在本公开的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本公开的保护范围之内。

Claims (10)

  1. 一种脉冲式电子顺磁共振谱仪，其特征在于包括：
    产生至少一种微波脉冲的微波激励产生单元；
    微波传导单元，包括谐振腔和传输微波的微波传输线，所述微波传输线连接于微波激励产生单元和谐振腔之间，所述谐振腔配置为置放样品；
    制冷机及磁体单元，包括对微波谐振腔实现0.1开尔文量级超低温冷却的制冷机，所述谐振腔设置于所述制冷机内，所微波传输线设置为穿入所述制冷机内并连接至所述谐振腔；制冷机及磁体单元还包括提供达到所述样品磁共振测试磁场的磁体，所述谐振腔设置于磁体的室温间隙中。
  2. 根据权利要求1所述的脉冲式电子顺磁共振谱仪，其特征在于，所述微波传导单元包括样品插杆，所述样品插杆一端安装有所述谐振腔，另一端与所述制冷机固定。
  3. 根据权利要求1所述的脉冲式电子顺磁共振谱仪，其特征在于，所述制冷机包括沿微波传输线穿过方向设置的多层冷盘，以逐级冷却微波传输线,所述微波传输线设置为逐层穿过所述冷盘。
  4. 根据权利要求1所述的脉冲式电子顺磁共振谱仪，其特征在于，所述微波谐振腔为包括L,S,X多种工作波段以及电子与核双共振的微波谐振腔。
  5. 根据权利要求4所述的脉冲式电子顺磁共振谱仪，其特征在于，所述微波传输线的导电介质为镀银不锈钢、镀银CuNi以及NbTi超导体。
  6. 根据权利要求1所述的脉冲式电子顺磁共振谱仪，其特征在于，所述制冷机及磁体单元还包括：
    电动导轨，所述导轨用于搬运和定位所述磁体。
  7. 根据权利要求6所述的脉冲式电子顺磁共振谱仪，其特征在于，所述制冷机尾端为圆柱形，外径兼容所述磁体间隙，所述制冷机尾端内径兼容所述谐振腔。
  8. 根据权利要求6所述的脉冲式电子顺磁共振谱仪，其特征在于，所述微波传输线在各级冷盘处安装热沉及转接头以充分冷却微波传输线线缆的外壳及内芯。
  9. 根据权利要求2所述的脉冲式电子顺磁共振谱仪，其特征在于，所述样品插杆包含导热金属材料。
  10. 根据权利要求3所述的脉冲式电子顺磁共振谱仪，其特征在于，各级所述冷盘外安装有热辐射屏蔽罩壳。
PCT/CN2018/078392 2017-08-10 2018-03-08 脉冲式电子顺磁共振谱仪 WO2019029161A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US16/331,457 US10802102B2 (en) 2017-08-10 2018-03-08 Pulsed electron paramagnetic resonance spectrometer
DE112018000097.4T DE112018000097T5 (de) 2017-08-10 2018-03-08 Gepulstes Elektronen-Paramagnetresonanzspektrometer
GB1902245.8A GB2567397B (en) 2017-08-10 2018-03-08 Pulsed electron paramagnetic resonance spectrometer
JP2019509501A JP2020504286A (ja) 2017-08-10 2018-03-08 パルス式電子常磁性共鳴分光計

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CNPCT/CN2017/096819 2017-08-10
CN2017096819 2017-08-10

Publications (1)

Publication Number Publication Date
WO2019029161A1 true WO2019029161A1 (zh) 2019-02-14

Family

ID=65272869

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2018/078392 WO2019029161A1 (zh) 2017-08-10 2018-03-08 脉冲式电子顺磁共振谱仪

Country Status (5)

Country Link
US (1) US10802102B2 (zh)
JP (2) JP2020504286A (zh)
DE (1) DE112018000097T5 (zh)
GB (1) GB2567397B (zh)
WO (1) WO2019029161A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3955377B1 (en) * 2020-08-12 2022-11-09 Bruker BioSpin GmbH Microwave coupling device for iris apertures, comprising a plurality of conductor loops
CN113030149B (zh) * 2021-03-10 2022-09-23 中国科学院山西煤炭化学研究所 一种用于电子顺磁共振仪的原位电化学反应池

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10160811A (ja) * 1996-11-26 1998-06-19 Nikkiso Co Ltd 電子スピン共鳴装置
CN1484510A (zh) * 2000-11-03 2004-03-24 ��ʢҩҵ���޹�˾ 极化nmr样本的方法和装置
CN101833072A (zh) * 2010-04-28 2010-09-15 中国科学院半导体研究所 一种基于永磁体实现磁场扫描的结构及方法
CN202305778U (zh) * 2011-08-29 2012-07-04 中国科学院上海技术物理研究所 一种用于半导体材料磁输运测试的样品杆
CN103529407A (zh) * 2013-10-10 2014-01-22 中国科学院上海技术物理研究所 一种无接触式低温磁输运测试的样品杆
CN106597332A (zh) * 2016-12-30 2017-04-26 中国科学技术大学 一种电子顺磁共振谱仪

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5739690A (en) * 1996-04-04 1998-04-14 Colorado Seminary Crossed-loop resonator structure for spectroscopy
JP3338381B2 (ja) * 1998-07-14 2002-10-28 大陽東洋酸素株式会社 核磁気共鳴分析装置用希釈冷凍機
GB0411072D0 (en) * 2004-05-18 2004-06-23 Oxford Instr Superconductivity Apparatus and method for performing in-vitro dnp-nmr measurements
DE102004053973B3 (de) * 2004-11-09 2006-07-20 Bruker Biospin Ag NMR-Spektrometer mit Refrigeratorkühlung
DE102004053972B3 (de) * 2004-11-09 2006-07-20 Bruker Biospin Gmbh NMR-Spektrometer mit gemeinsamen Refrigerator zum Kühlen von NMR-Probenkopf und Kryostat
EP2035818A1 (en) * 2006-06-15 2009-03-18 Technion Research & Development Foundation LTD. Probe and system for electron spin resonance imaging
US8610434B2 (en) * 2011-07-21 2013-12-17 ColdEdge Technologies, Inc. Cryogen-free cooling system for electron paramagnetic resonance system
GB2493553B (en) * 2011-08-11 2017-09-13 Oxford Instr Nanotechnology Tools Ltd Cryogenic cooling apparatus and method
GB2498181A (en) * 2011-12-29 2013-07-10 Bruker Biospin Gmbh Device and method for rapid dynamic nuclear polarisation
JP2014200428A (ja) * 2013-04-04 2014-10-27 富士電機株式会社 均等磁場発生電磁石装置
JP6194552B2 (ja) * 2013-11-25 2017-09-13 日本電子株式会社 Ｅｓｒ用マイクロ波共振器
EP3070488B1 (en) * 2015-03-18 2017-08-30 Bruker BioSpin GmbH Epr microwave cavity for small magnet airgaps

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10160811A (ja) * 1996-11-26 1998-06-19 Nikkiso Co Ltd 電子スピン共鳴装置
CN1484510A (zh) * 2000-11-03 2004-03-24 ��ʢҩҵ���޹�˾ 极化nmr样本的方法和装置
CN101833072A (zh) * 2010-04-28 2010-09-15 中国科学院半导体研究所 一种基于永磁体实现磁场扫描的结构及方法
CN202305778U (zh) * 2011-08-29 2012-07-04 中国科学院上海技术物理研究所 一种用于半导体材料磁输运测试的样品杆
CN103529407A (zh) * 2013-10-10 2014-01-22 中国科学院上海技术物理研究所 一种无接触式低温磁输运测试的样品杆
CN106597332A (zh) * 2016-12-30 2017-04-26 中国科学技术大学 一种电子顺磁共振谱仪

Also Published As

Publication number Publication date
GB2567397B (en) 2022-06-22
JP2020504286A (ja) 2020-02-06
JP2021099377A (ja) 2021-07-01
GB2567397A (en) 2019-04-10
US10802102B2 (en) 2020-10-13
DE112018000097T5 (de) 2019-08-14
GB201902245D0 (en) 2019-04-03
US20200182955A1 (en) 2020-06-11

Similar Documents

Publication Publication Date Title
Asztalos et al. SQUID-based microwave cavity search for dark-matter axions
Bloembergen On the interaction of nuclear spins in a crystalline lattice
Bloembergen et al. Relaxation effects in nuclear magnetic resonance absorption
Peng et al. Cryogenic cavity detector for a large-scale cold dark-matter axion search
Weickert et al. Implementation of specific-heat and NMR experiments in the 1500 ms long-pulse magnet at the Hochfeld-Magnetlabor Dresden
Shtirberg et al. High-sensitivity Q-band electron spin resonance imaging system with submicron resolution
JP2021099377A (ja) パルス式電子常磁性共鳴分光計
Holley et al. A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment
Thomas Polarised Targets for 4 π Detectors at MAMI
Liu et al. Pulsed-field nuclear magnetic resonance: Status and prospects
CN208443995U (zh) 脉冲式电子顺磁共振谱仪
Hotra et al. Current status and development prospects of nuclear quadrupole resonance pulsed spectroscopy methods: A review
Kleindienst et al. Development of an optimized quadrupole resonator at hzb
Truedson et al. High‐field effective linewidth and eddy current losses in moderate conductivity single‐crystal M‐type barium hexagonal ferrite disks at 10–60 GHz
Jena et al. Isotope effect on the electronic spin density in pdh superconductor
Rana et al. Magnetic fluctuations in the itinerant ferromagnet LaCrGe 3 studied by La 139 NMR
Xin et al. Toward the Mott state with magnetic cluster formation in heavily Cu-doped NaFe 1− x Cu x As
CN109387799A (zh) 脉冲式电子顺磁共振谱仪
US20230184850A1 (en) Precision magnetometer
Ono et al. Experimental investigation of RF magnetic field homogeneity in a bridged loop‐gap resonator
O’Reilly et al. SQUID-detected FMR: Resonance in single crystalline and polycrystalline yttrium iron garnet
Crescini et al. Operation of a ferromagnetic axion haloscope at [Formula omitted]
Ohta et al. Development of 17T-NMR system for measurement of polarized HD and 3He targets
Wang et al. Time response of spin-polarized rubidium thermal gas with radio-frequency pulse driving
Frait et al. Precision g-factor measurements of electron paramagnetic resonance standards

Legal Events

Date Code Title Description
ENP Entry into the national phase

Ref document number: 2019509501

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 201902245

Country of ref document: GB

Kind code of ref document: A

Free format text: PCT FILING DATE = 20180308

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18843206

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 18843206

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 18843206

Country of ref document: EP

Kind code of ref document: A1

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 18/11/2020)

122 Ep: pct application non-entry in european phase

Ref document number: 18843206

Country of ref document: EP

Kind code of ref document: A1