Nuclear reactor temperature sensing device and nuclear reactor temperature locking method

Abstract

The application discloses an atomic furnace temperature sensing device and an atomic furnace temperature locking method, and relates to the technical field of experimental atomic physics. The method comprises the following steps: measuring temperature information of an atomic furnace by using the temperature sensing device under a stable environment temperature; measuring fluorescence signal intensity information under the temperature by using a photoelectric sensor; fitting atomic furnace temperature information and fluorescence signal intensity information obtained for several times to obtain a corresponding relationship curve of the temperature of the atomic furnace and the fluorescence signal intensity; and detecting the change of the fluorescence signal intensity in real time by using the photoelectric sensor, and generating a feedback signal of heating power of the atomic furnace according to the corresponding relationship curve of the temperature and the fluorescence signal intensity. The method can more accurately lock the temperature, and thus can more accurately measure and control the temperature of the atomic furnace.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of experimental atomic physics, and particularly relates to an atomic furnace temperature sensing device and an atomic furnace temperature locking method. BACKGROUND

[0002] In an atomic beam experiment, accurate control of the temperature of an atomic furnace is an important link to ensure the stability of the experiment. At present, the commonly used method is to install a thermistor outside the atomic furnace and achieve temperature control in combination with a locking loop. However, since the thermistor cannot completely adhere to the surface of the cesium furnace, the temperature measured thereby is not accurate enough and is affected by the ambient temperature, thereby affecting the accuracy and stability of the experiment. SUMMARY

[0003] The technical problem to be solved by the present application is how to provide a device and method capable of more accurately locking the temperature and thus more accurately measuring and controlling the temperature of an atomic furnace.

[0004] To solve the above technical problem, the technical solution adopted by the present application is: an atomic furnace temperature sensing device, comprising a thermistor, the thermistor comprising a resistance main body and a first pin and a second pin connected at both ends of the resistance main body, the measuring device further comprising a metal sleeve, the first pin being inserted into the metal sleeve, and a free end of the first pin forming a bent portion after extending out of the metal sleeve, the bent portion being in contact with the outer wall of the metal sleeve, the resistance main body being partially located in the metal sleeve or the resistance main body being located outside the metal sleeve, the metal sleeve being used to directly contact the furnace body of the atomic furnace.

[0005] The present application further discloses an atomic furnace temperature locking method, comprising the following steps:

[0006] In a stable ambient temperature, the temperature information of the atomic furnace is measured by using the temperature sensing device;

[0007] An atomic beam hole is formed on the furnace body of the atomic furnace, and a collimator is arranged outside the atomic beam hole, the atomic furnace emitting an atomic beam outward through the collimator; the power of a laser is kept constant to generate constant laser, and the generated laser is used to act on the atomic beam to generate a measurable fluorescent signal; the power of the atomic furnace is changed and measured for several times, the temperature of the atomic furnace is measured by using the temperature sensing device, and the fluorescent signal intensity information at the temperature is measured by using a photoelectric sensor, the atomic furnace temperature information and the fluorescent signal intensity information obtained for several times are fitted to obtain a corresponding relationship curve between the temperature of the atomic furnace and the fluorescent signal intensity;

[0008] The change of the fluorescent signal intensity is detected in real time by the photoelectric sensor, a feedback signal of the heating power of the atomic reactor is generated according to the corresponding relation curve of the temperature and the fluorescent signal intensity, and the feedback signal is input into the temperature locking loop for real-time adjustment of the heating power of the atomic reactor, so that the locking control of the atomic reactor temperature is realized.

[0009] The temperature sensing device has the copper sleeve structure, so that the thermistor is closely attached to the atomic reactor, the temperature of the atomic reactor is better reflected, and the temperature measurement is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0010] The application will be further described in detail below with reference to the drawings and specific embodiments.

[0011] Figure 1 is a structural schematic diagram of the temperature sensing device in the embodiment of the application;

[0012] Figure 2 is an assembly diagram of the temperature sensing device and the atomic reactor in the embodiment of the application;

[0013] Figure 3 is a structural schematic diagram of the temperature sensing device and the atomic reactor after assembly in the embodiment of the application;

[0014] Figure 4 is a whole flow chart of the method in the embodiment of the application;

[0015] Figure 5 is a measurement principle block diagram of the method in the embodiment of the application;

[0016] Figure 6 is a relation curve diagram of the atomic reactor temperature and the atomic beam intensity in the method in the embodiment of the application;

[0017] Figure 7 is a relation curve diagram of the atomic reactor temperature and the fluorescent signal intensity in the method in the embodiment of the application;

[0018] 1, thermistor; 1-1, resistance body; 1-2, first pin; 1-3, second pin; 2, metal sleeve; 3, furnace body; 4, fixing clamp; 5, temperature sensing device; 6, collimator. DETAILED DESCRIPTION

[0019] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0020] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and a person of ordinary skill in the art can make similar generalizations without departing from the spirit and scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0021] As shown in Figures 1-2 Embodiments of the present application disclose an atomic furnace temperature sensing device, which comprises a thermistor 1, the thermistor 1 comprises a resistance main body 1-1 and a first pin 1-2 and a second pin 1-3 connected at both ends of the resistance main body 1-1.

[0022] Since the thermistor cannot really measure the internal temperature of the atomic furnace but only adheres to the outer wall thereof to indirectly measure the temperature thereof, the temperature measured by the thermistor is between the ambient temperature and the atomic furnace temperature, that is:

[0023] T 热敏 =k1T 原子炉 +k2T 环境 (1)

[0024] Wherein, k1 and k2 are two fixed coefficients and satisfy k1+k2=1. In the scheme of locking the atomic furnace temperature by using the thermistor, it is considered that k2=0, then the thermistor represents the atomic furnace temperature and is irrelevant to the ambient temperature. In actual situation, k2≠0, because the atomic furnace cannot be completely thermally insulated from the environment, there is heat conduction and radiation. It can be further calculated that:

[0025]

[0026] When the ambient temperature changes, the temperature measured by the thermistor remains unchanged, and the atomic furnace temperature changes.

[0027] In order to solve the above problems, the present application proposes a new thermistor fixing method to reduce k2, and provides a new atomic furnace temperature locking scheme to further reduce the influence of the ambient temperature on the furnace temperature locking.

[0028] The novel thermistor fixing structure is as follows: the measuring device further comprises a metal sleeve 2, preferably an oxygen-free copper sleeve; the first pin 1-2 is inserted into the metal sleeve 2, and the free end of the first pin 1-2 is bent to form a bending part which is in contact with the outer wall of the metal sleeve 2; the resistance main body 1-1 is partially located in the metal sleeve 2 or outside the metal sleeve 2, and the metal sleeve 2 is used to directly contact the furnace body 3 of the atomic furnace which is an oxygen-free copper furnace body. In addition, the measuring device can further comprise a fixing clamp 4 which is used to fix the second pin 1-3.

[0029] In the novel thermistor fixing method, in order to ensure the close contact between the thermistor and the atomic furnace, an oxygen-free copper sleeve is used to cover one end of the thermistor, and the pin of the thermistor which extends out of the oxygen-free copper sleeve is bent to hook the oxygen-free copper sleeve, and then the whole is implanted into the cavity reserved in the atomic furnace. Figure 2 The assembly diagram of the atomic furnace and the thermistor is shown. During the implantation process, due to the deformation of the thermistor pin and the copper sleeve, the metal parts are pressed against each other to form a good conductor of heat, thereby reducing k2 in formula 1 and reducing the influence of the environmental temperature on the furnace temperature measurement. Since deformation is involved in the implantation process, the implantation resistance is large, so a corresponding metal sleeve is needed. By fixing the metal sleeve to the outer end of the thermistor and knocking the metal sleeve, the implantation can be completed without damaging the thermistor and the atomic furnace. Figure 3 The atomic furnace and the thermistor after fixing are shown.

[0030] In order to more accurately measure and control the temperature of the atomic furnace, as shown in Figure 4 The application further discloses an atomic furnace temperature locking method, and the measuring principle is as shown in Figure 5 The atomic furnace temperature locking method comprises the following steps:

[0031] S1: measuring the temperature information of the atomic furnace by using the temperature sensing device 5 under a stable environmental temperature;

[0032] S2: an atomic beam hole is formed on the furnace body 3 of the atomic furnace, and a collimator 6 is arranged outside the atomic beam hole, and the atomic furnace emits an atomic beam through the collimator 6; the power of the laser is constant, so that a constant laser is generated, and the generated laser acts on the atomic beam to generate a measurable fluorescent signal; the power of the atomic furnace is changed and measured for several times, the temperature of the atomic furnace is measured by the temperature sensing device 5, and the fluorescent signal intensity information at the temperature is measured by a photoelectric sensor; the atomic furnace temperature information and the fluorescent signal intensity information obtained for several times are fitted to obtain a corresponding relationship curve between the temperature of the atomic furnace and the fluorescent signal intensity;

[0033] In the new temperature locking method, the fluorescence signal is generated by the interaction of laser and atomic beam, and the atomic oven temperature is locked by detecting the change of fluorescence intensity. The locking process of this scheme is not affected by the environmental temperature.

[0034] The oven temperature is positively correlated with the atomic beam intensity, and the functional relationship is independent of the environmental temperature. The oven temperature T and the saturated vapor pressure P of the atoms inside the oven can be calculated by the following formula v Relationship:

[0035]

[0036] (unit: Torr, 1 Torr = 133.32 Pa). Then the atomic density n is calculated according to the state equation:

[0037] P v = nk B T (4)

[0038] where k B is the Boltzmann constant. In order to make the divergence angle of the atomic beam smaller, the collimator composed of a large number of micro-holes needs to be increased, because the existence of the collimator, most of the atoms will be bounced back to the cesium oven instead of being sprayed out. In the presence of the collimator, the beam intensity sprayed out of the oven is given by the following expression (i at the number of atoms sprayed out per unit time):

[0039]

[0040] where K is the collimator coefficient, v is the average speed of the atoms, S is the area of each micro-hole, and M is the number of micro-holes. where a z is the micro-hole radius, l z is the tube length of the collimator, and m sat is the atomic mass. Figure 6 The functional relationship is given, and as an example: M = 512, lz = 3.5 m, az = 0.03 m, and the atom is Cs-133.

[0041] The atomic beam intensity is positively correlated with the fluorescence signal intensity, and the functional relationship is independent of the environmental temperature. The number of photons emitted by an atom under unit light is as follows,

[0042]

[0043] where Γ is the natural line width, Δ is the detuning (this value is zero when using and detecting atoms), I is the light intensity, I sat is the saturation light intensity, which satisfies:

[0044]

[0045] where Ω is the Rabi oscillation angular frequency.

[0046] Considering the size of the spot, the total number of photons released by the atoms per unit time under the spot can be calculated. Take the spot as a uniform spot with a radius of R. Take the center point of the spot as the 0 point,

[0047] Total number of photons released per unit time:

[0048]

[0049] where D is the distance from the atomic furnace to the atomic and laser interaction area (considering the existence of divergence), and v is the average speed of the atoms.

[0050] Through optical simulation and other means, the proportion γ of these photons entering the photoelectric sensor can be obtained. Combined with the photon number of the photoelectric sensor, the conversion efficiency β of the current, and the amplification coefficient α of the current-to-voltage, the relationship between the fluorescence signal strength U1 (unit: volt) read from the photoelectric sensor and the atomic beam strength can be obtained:

[0051]

[0052] where e is the electronic charge.

[0053] It can be seen that the read fluorescence signal U1 and the atomic beam strength I at are proportional, and the functional relationship between the fluorescence signal U and the atomic furnace temperature T can be further obtained. The actual fluorescence signal U = U1 + U2, where U2 is the contribution of the spatial scattering into the photoelectric sensor. It satisfies:

[0054] U2 = αβγe·IπR 2 μ / (h / λ) (10)

[0055] where μ is the scattering light receiving efficiency, h is the Planck constant, and λ is the detection light wavelength.

[0056] It can be seen that the atomic furnace temperature and the fluorescence signal strength are positively correlated, and the functional relationship is independent of the environmental temperature:

[0057]

[0058] Figure 7 The relevant curves are given, and as an example, take: α = 20k, β = 50%, γ = 50%, μ = 10%, D = 300mm, R = 3mm, Γ = 5MHz, I = 70W / m 2 sat 2 .

[0059] ​​In practice, the confirmation of the above parameters is complicated, and the use of a calibration method can more efficiently determine the relationship between the fluorescence signal and the atomic furnace temperature. By simplifying, a simpler expression of equation (11) can be given:

[0060]

[0061] where P v (T) is the saturated vapor pressure in equation (2), and A and B are two parameters to be fitted. From the above results, it can be seen that measuring at least two points can complete the calibration of the functional relationship, i.e., determining A and B.

[0062] Since there is a direct functional relationship between the fluorescence signal and the atomic furnace temperature, real-time measurement of the atomic fluorescence intensity can be used for real-time feedback control of the temperature, and since the functional relationship is independent of the environmental temperature, stable operation can be maintained under changes in the environmental temperature.

[0063] S3: Real-time detection of the change in fluorescence signal intensity by a photoelectric sensor, generation of a feedback signal for the heating power of the atomic furnace according to the corresponding relationship curve between the temperature and the fluorescence signal intensity, and input of the feedback signal into the temperature lock loop for real-time adjustment of the heating power of the atomic furnace, thereby achieving lock control of the atomic furnace temperature.

[0064] In summary, the method described in the present application measures the temperature using a thermistor under stable environmental temperature. After laser power is locked, the laser interacts with the atomic beam and measures the fluorescence signal intensity to obtain the corresponding relationship between the temperature and the fluorescence signal intensity. At this time, the temperature is the temperature measured by the thermistor, but since the environmental temperature is constant, the corresponding atomic furnace temperature is also a constant value. That is, although there is a deviation between the atomic furnace temperature and the thermistor measured temperature (equation (2)), this deviation is a constant value. In the subsequent lock, the temperature measured by the thermistor is no longer relied on, so this constant deviation will not change during the lock process.

[0065] After the fluorescence signal is locked at the measured value, since the relationship between the fluorescence signal and the atomic furnace temperature is not affected by the environmental temperature, the influence of changes in the environmental temperature does not need to be considered during the operation of the system, i.e., the atomic furnace temperature lock of the present patent is achieved.

Claims

1. A method of atomic reactor temperature lock characterized by It comprises the following steps: The temperature of the atomic reactor is measured by using a temperature sensing device (5) of the atomic reactor at a stable ambient temperature; the temperature sensing device comprises a thermistor (1) comprising a resistance body (1-1) and a first pin (1-2) and a second pin (1-3) connected at both ends of the resistance body (1-1), and further comprises a metal sleeve (2), the first pin (1-2) is inserted into the metal sleeve (2), and the free end of the first pin (1-2) extends out of the metal sleeve (2) to form a bending part, the bending part is in contact with the outer wall of the metal sleeve (2), and the resistance body (1-1) is partially located in the metal sleeve (2) or located outside the metal sleeve (2), the metal sleeve (2) is used for direct contact with the furnace body (3) of the atomic reactor; An atomic beam hole is formed on the furnace body (3) of the atomic reactor, and a collimator (6) is arranged outside the atomic beam hole, the atomic reactor emits an atomic beam outward through the collimator (6); the power of a laser is kept constant to generate constant laser, and the generated laser is used to act on the atomic beam to generate a measurable fluorescence signal; the power of the atomic reactor is changed and several measurements are performed, the temperature of the atomic reactor is measured by using the temperature sensing device (5), and the fluorescence signal intensity information at the temperature is measured by using a photoelectric sensor, the atomic reactor temperature information and the fluorescence signal intensity information obtained in several times are fitted to obtain a corresponding relationship curve between the temperature of the atomic reactor and the fluorescence signal intensity; The change of the fluorescence signal intensity is detected in real time by using a photoelectric sensor, the temperature of the atomic reactor is calculated according to the corresponding relationship curve between the temperature and the fluorescence signal intensity, a feedback signal of the heating power of the atomic reactor is generated, and the feedback signal is input into a temperature locking loop for real-time adjustment of the heating power of the atomic reactor, so that the temperature of the atomic reactor is locked and controlled; The temperature of the atomic reactor is positively correlated with the fluorescence signal intensity; The formula of the corresponding relationship curve between the temperature of the atomic reactor and the fluorescence signal intensity is: ； wherein, is the atomic saturated vapor pressure, is the fluorescence signal intensity, is the atomic reactor temperature, and the undetermined coefficients are calibrated by using at least two sets of atomic reactor temperature information and fluorescence signal intensity information A and B to obtain a corresponding relationship curve.

2. The atomic furnace temperature locking method according to claim 1, characterized by: The metal sleeve (2) is an oxygen-free copper sleeve.

3. The atomic furnace temperature locking method as claimed in claim 1, wherein: The temperature sensing device further comprises a fixing clamp (4) for fixing the second pin (1-3).

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