A 201 Hg + isotope mercury ion microwave frequency standard device

Abstract

The present invention discloses a <supgt;201< / supgt;Hg<supgt;+< / supgt; isotope mercury ion microwave frequency standard device. In a specific embodiment, the device includes: a helium gas cylinder, a helium leak, and a mercury-201 isotope furnace connected in sequence for generating mercury-201 isotope; the mercury-201 isotope furnace is connected to a hybrid ion trap through a stainless steel pipe; the hybrid ion trap is connected with an optical path shaping device, and a mercury-198 pumping spectrum lamp is connected to the light input side of the optical path shaping device. The pumping light formed by the mercury-198 pumping spectrum lamp is shaped into a rectangular light spot by the optical path shaping device and enters the hybrid ion trap; a photon collection device is arranged at the second end face of the hybrid ion trap; the servo control device receives the transition fluorescence signal through the photon collection device to obtain an error voltage, inputs the error voltage to the voltage input end of the local oscillator through a cable, adjusts the frequency output of the local oscillator, and its output end is connected to a pyramidal horn through a 29.9 GHz frequency doubling link and radiates to the hybrid ion trap.

Description

Technical Field

[0001] The present invention relates to the field of microwave frequency standards, and particularly to a 201 Hg + isotope mercury ion microwave frequency standard device. Background Art

[0002] Mercury ion microwave frequency standards are a new type of frequency standards, which adopt a completely new working principle different from traditional atomic frequency standards such as hydrogen, rubidium, and cesium. They have the inherent characteristics of being basically unaffected by the disturbance of physical particles and external fields, having small motion effects, and long coherence times of quantum states. Their spectral line widths are extremely narrow, and various frequency shifts are very small. One of the main reasons is that by applying an electrostatic field, a magnetic field, or a radio frequency field in an ion trap, the working ions are trapped in the center of the ion trap in ultra-high vacuum, making the ions completely isolated and in a "completely stationary state", not being interfered by the outside world. Therefore, the performance indicators of ion microwave frequency standards can be greatly improved. Ion microwave frequency standards use a spectral lamp to pump the hyperfine energy levels of ions. Under the action of microwaves, atoms in high energy levels jump to low energy levels, generating fluorescence signals, which are collected by the detection system. When the microwave signal frequency is swept within a certain range, the optical detection system will obtain Ramsey signals. Locking the standard signal source on the Ramsey signals can obtain an output signal with extremely high stability.

[0003] Currently, when conducting research on mercury ion microwave frequency standards, most use 199 Hg isotopes. Due to the characteristics of this isotope, the following problems exist in its research: 1. 199 The spectral lines required for pumping of 202 Hg isotopes have a low coincidence with the spectral lines emitted by the pumping spectral lamp Summary of the Invention

[0004] The purpose of the present invention is to provide a 201 Hg + isotope mercury ion microwave frequency standard device to solve the problems such as low pumping efficiency and low signal-to-noise ratio of current mercury ion microwave frequency standards.

[0005] The 201 Hg + isotope mercury ion microwave frequency standard device provided by the present invention includes: a helium gas cylinder, a helium leak, and a mercury-201 isotope furnace connected in sequence, which are used to generate mercury-201 isotopes;

[0006] The mercury-201 isotope furnace is connected to a hybrid ion trap through a vacuum stainless steel pipe, and the generated mercury-201 isotopes enter the hybrid ion trap through the vacuum stainless steel pipe;

[0007] A light path shaping device is vertically connected to the first end face of the hybrid ion trap. A mercury-198 pumping spectral lamp is connected to the light incident side of the light path shaping device. The pumping light formed by the mercury-198 pumping spectral lamp is shaped into a rectangular light spot by the light path shaping device and enters the hybrid ion trap.

[0008] The photon collection device is vertically arranged on the second end face of the hybrid ion trap and is used for collecting ion transition fluorescence signals.

[0009] The photon collection device is connected to the servo control device through a cable. The servo control device receives the transition fluorescence signal to obtain an error voltage, inputs the error voltage to the voltage input end of the local oscillator through the cable, adjusts the frequency output of the local oscillator, and its output end is connected to a horn antenna through a 29.9 GHz frequency multiplication link, and radiates to the hybrid ion trap through the horn antenna.

[0010] Further, the device further includes:

[0011] A vacuum pump group, which is connected to the hybrid ion trap through a CF35 interface and is used to prepare the vacuum degree inside the hybrid ion trap.

[0012] Further, the hybrid ion trap includes a quadrupole ion trap, a dodecapole ion trap and a vacuum chamber, where

[0013] The quadrupole ion trap is used for the preparation of ion states, the dodecapole ion trap is used for microwave exciting ions to obtain the required transition signals, and the vacuum chamber is used to provide a working space for ion confinement.

[0014] Further, the external interface of the helium leak is connected to the helium gas cylinder through a vacuum hose.

[0015] Further, an electron gun is also connected to the hybrid ion trap. The electron gun is fixed to the end face of the quadrupole ion trap by screws, and its center is directly aligned with the center line of the quadrupole ion trap, so that electrons can reach the center of the ion trap to ionize atoms.

[0016] Further, the vacuum pump group adopts three-stage pumps, namely a dry pump, a molecular pump and an ion pump, so that the vacuum degree inside the hybrid ion trap reaches 1E-8 Pa.

[0017] Further, the mercury-201 isotope furnace is provided with a temperature measuring resistor, and its temperature is controlled at 220 °C to 270 °C, so that the saturated vapor pressure inside the hybrid ion trap is maintained in the range of 5E-8 Pa to 1E-7 Pa.

[0018] Further, the cathode filament current of the electron gun is controlled at 1.4 A to 1.6 A.

[0019] Further, a radio frequency field with a frequency of 0.5 MHz to 2 MHz and a peak-to-peak voltage of 800 V to 1200 V and an electrostatic field of 200 V need to be applied to the quadrupole ion trap.

[0020] Further, the pumping light generated by the mercury-198 pumping spectrum lamp is used to pump the mercury ions trapped in the quadrupole ion trap into the dodecapole ion trap.

[0021] The beneficial effects of the present invention are as follows:

[0022] In view of the problems existing in the prior art, the present application provides an 201 Hg + isotopic mercury ion microwave frequency standard device, which uses 198 Hg pumping spectrum lamp to pump 201 Hg + ions. The spectral line coincidence degree of the two is higher, and the pumping efficiency is high. The error voltage is obtained by using the collected signal, and the output frequency of the local oscillator is controlled to obtain a more accurate and stable frequency signal, improving the pumping frequency and the signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Show a 201 Hg + isotopic mercury ion microwave frequency standard device of the present invention.

[0024] Figure 2 Show 198 Hg + , 199 Hg + , 201 Hg + , 202 Hg + emission spectral line schematic diagram. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with the preferred embodiments and the drawings. Similar components in the drawings are denoted by the same reference numerals. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0026] As Figure 1 shown, an 201 Hg + isotopic mercury ion microwave frequency standard device provided by the present invention includes: a helium gas cylinder, a helium leak, and a mercury-201 isotope furnace connected in sequence, which are used to generate mercury-201 isotopes;

[0027] The mercury-201 isotope furnace is connected to the hybrid ion trap through a stainless-steel pipe, and the generated mercury-201 isotope enters the hybrid ion trap through the stainless-steel pipe;

[0028] A light path shaping device is vertically connected to the first end face of the hybrid ion trap, and a mercury-198 pumping spectrum lamp is connected to the light incident side of the light path shaping device. The pumping light formed by the mercury-198 pumping spectrum lamp is shaped into a rectangular light spot by the light path shaping device and enters the hybrid ion trap;

[0029] The photon collection device is vertically arranged on the second end face of the hybrid ion trap for collecting ion transition fluorescence signals;

[0030] The photon collection device is connected to the servo control device through a cable. The servo control device receives the transition fluorescence signal to obtain an error voltage, inputs the error voltage to the voltage input end of the local oscillator through the cable, adjusts the frequency output of the local oscillator, and its output end is connected to a horn antenna through a 29.9 GHz frequency doubling link, and radiates to the hybrid ion trap through the horn antenna.

[0031] In this solution, 198 Hg + is pumped by a pumping spectrum lamp 201 Hg + ions. As Figure 2 described, the spectral line coincidence degree between the two is higher than that between 199 Hg + and 202 Hg + Therefore, the pumping efficiency is high. The error voltage is obtained by using the collected signal, the output frequency of the local oscillator is controlled, and a more accurate and stable frequency signal is obtained, improving the pumping frequency and signal-to-noise ratio.

[0032] In a specific embodiment, the hybrid ion trap is connected to a vacuum pump group through a CF35 interface, connected to a helium leak through a CF16 interface, connected to the mercury-201 isotope furnace through a vacuum stainless-steel pipe, and the external interface of the helium leak is connected to a helium gas cylinder through a vacuum hose;

[0033] In a specific embodiment, the vacuum pump group adopts three-stage pumps: a dry pump, a molecular pump, and an ion pump to make the vacuum degree in the hybrid ion trap reach 1E-8 Pa; the mercury-201 isotope furnace is provided with a temperature-measuring resistor, generates the required atoms by heating, and obtains an appropriate atomic density by controlling the temperature. Its temperature is controlled at 220 °C to 270 °C, so that the saturated vapor pressure in the hybrid ion trap is maintained in the range of 5E-8 Pa to 1E-7 Pa.

[0034] In a specific embodiment, the hybrid ion trap includes a quadrupole ion trap, a dodecapole ion trap, and a vacuum chamber. Among them,

[0035] The quadrupole ion trap is used for the preparation of ion states, the dodecapole ion trap is used for microwave exciting ions to obtain the required transition signals, and the vacuum chamber is used to provide a working space for ion confinement.

[0036] Among them,

[0037] The quadrupole electron trap needs to apply a radio frequency field with a frequency of 0.5 MHz to 2 MHz and a peak-to-peak voltage of 800 V to 1200 V, as well as an electrostatic field of 200 V.

[0038] In a specific embodiment, the hybrid ion trap is further connected with an electron gun. The electron gun is fixed to the end face of the quadrupole ion trap by screws, and its center is directly aligned with the center line of the quadrupole ion trap, so that electrons can reach the center of the ion trap to ionize atoms. The cathode filament current of the electron gun is controlled at 1.4 A to 1.6 A.

[0039] In a specific embodiment, a mercury-198 pumping spectrum lamp is connected to the light incident side of the optical path shaping device. The pumping light formed by the mercury-198 pumping spectrum lamp is shaped into a rectangular light spot by the optical path shaping device and enters the hybrid ion trap. The light output side of the optical path shaping device is connected to the quadrupole ion trap.

[0040] In a specific embodiment, the size of the rectangular light spot is 20 mm × 3 mm.

[0041] In a specific embodiment, the photon collection device is fixed directly above the ion trap by screws and is perpendicular to the direction of the pumping spectrum lamp, and is used to collect the fluorescence after ion transition.

[0042] In a specific embodiment, the radiation space of the microwave field emitted by the horn antenna is the dodecapole ion trap space.

[0043] In this embodiment, the trapped mercury ions are pumped by the pumping spectrum lamp to complete the preparation of the state. Then the ions are transferred from the quadrupole ion trap to the dodecapole ion trap. A microwave field is applied through a 29.9 GHz frequency doubling link and a horn antenna to generate mercury ion transition fluorescence signals. Using the collected signals and through algorithms, an error voltage is obtained to control the output frequency of the local oscillator, obtaining a more accurate and stable frequency signal, and improving the pumping frequency and signal-to-noise ratio.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to enumerate all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A 201 Hg + isotope mercury ion microwave frequency standard device, It is characterized in that the device includes: a helium gas cylinder, a helium leak detector, and a mercury-201 isotope furnace connected in sequence, which are used to generate mercury-201 isotope; the mercury-201 isotope furnace is connected to a hybrid ion trap through a stainless steel pipe, and the generated mercury-201 isotope enters the hybrid ion trap through the stainless steel pipe; an optical path shaping device is vertically connected to the first end face of the hybrid ion trap, a mercury-198 pumping spectrum lamp is connected to the light incident side of the optical path shaping device, and the pumping light formed by the mercury-198 pumping spectrum lamp is shaped into a rectangular light spot by the optical path shaping device and enters the hybrid ion trap; the photon collection device is vertically arranged on the second end face of the hybrid ion trap and is used to collect ion transition fluorescence signals; the photon collection device is connected to a servo control device through a cable. The servo control device receives the transition fluorescence signal to obtain an error voltage, inputs the error voltage to the voltage input end of the local oscillator through the cable, adjusts the frequency output of the local oscillator, and its output end is connected to a horn antenna through a 29.9 GHz frequency multiplication link, and radiates to the hybrid ion trap through the horn antenna.

2. The device according to claim 1, it is characterized in that the device further includes: a vacuum pump group, which is connected to the hybrid ion trap through a CF35 interface and is used to prepare the vacuum degree in the hybrid ion trap.

3. The device according to claim 2, it is characterized in that the hybrid ion trap includes a quadrupole ion trap, a dodecapole ion trap, and a vacuum chamber, wherein the quadrupole ion trap is used for the preparation of ion states, the dodecapole ion trap is used for microwave exciting ions to obtain the required transition signals, and the vacuum chamber is used to provide a working space for ion confinement.

4. The device according to claim 1, it is characterized in that the external interface of the helium leak detector is connected to the helium gas cylinder through a vacuum hose.

5. The device according to claim 3, it is characterized in that the hybrid ion trap is further connected with an electron gun, the electron gun is fixed to the end face of the quadrupole ion trap by screws, and its center is directly aligned with the center line of the quadrupole ion trap, so that electrons can reach the center of the ion trap to ionize atoms.

6. The device according to claim 5, it is characterized in that the vacuum pump group adopts three-stage pumps, namely a dry pump, a molecular pump, and an ion pump, so that the vacuum degree in the hybrid ion trap reaches 1E-8 Pa.

7. The device according to claim 6, it is characterized in that the mercury-201 isotope furnace is provided with a temperature measuring resistor, and its temperature is controlled at 220 °C to 270 °C, so that the saturated vapor pressure in the hybrid ion trap is maintained in the range of 5E-8 Pa to 1E-7 Pa.

8. The device according to claim 7, it is characterized in that the cathode filament current of the electron gun is controlled at 1.4 A to 1.6 A.

9. The device according to claim 8, it is characterized in that the quadrupole electron trap needs to apply a radio frequency field with a frequency of 0.5 MHz to 2 MHz and a voltage peak-to-peak value of 800 V to 1200 V and an electrostatic field of 200 V.

10. The device according to claim 9, it is characterized in that The pumping light generated by the mercury-198 pumping spectral lamp is used to pump the mercury ions trapped in the quadrupole ion trap into the dodecapole ion trap.

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