Atomic furnace temperature sensing device and atomic furnace temperature locking method

Abstract

The invention 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 the atomic furnace by using the temperature sensing device at a stable environment temperature; measuring fluorescence signal intensity information at the temperature through a photoelectric sensor, and fitting the obtained temperature information of the atomic furnace and the fluorescence signal intensity information for a plurality of times to obtain a corresponding relation curve of the temperature of the atomic furnace and the fluorescence signal intensity; the change of the fluorescence signal intensity is detected in real time through a photoelectric sensor, and a feedback signal of the heating power of the atomic furnace is generated according to the corresponding relation curve of the temperature and the fluorescence signal intensity. According to the method, the temperature can be locked more accurately, so that the temperature of the atomic furnace can be measured and controlled more accurately.

Description

Technical Field

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

[0002] In atomic beam experiments, the precise control of the atomic furnace temperature is an important link to ensure the stability of the experiment. Currently, the common method is to install a thermistor outside the atomic furnace and combine it with a locking loop to achieve temperature control. However, since the thermistor cannot be completely attached to the surface of the cesium furnace, the measured temperature is not accurate enough and is affected by the ambient temperature, thus affecting the accuracy and stability of the experiment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is how to provide a device and method that can lock the temperature more accurately, so as to measure and control the atomic furnace temperature more precisely.

[0004] To solve the above technical problem, the technical solution adopted by the present invention is: an atomic furnace temperature sensing device, including a thermistor, the thermistor includes a resistor body and a first pin and a second pin connected to both ends of the resistor body, the measuring device further includes a metal sleeve, the first pin is inserted into the metal sleeve, and the free end of the first pin forms a bent portion after extending out of the metal sleeve, the bent portion is in contact with the outer wall of the metal sleeve, part of the resistor body is located inside the metal sleeve or the resistor body is located outside the metal sleeve, and the metal sleeve is used for direct contact with the furnace body of the atomic furnace.

[0005] The present invention also discloses an atomic furnace temperature locking method, including the following steps:

[0006] Under a stable ambient temperature, use the temperature sensing device to measure the temperature information of the atomic furnace;

[0007] An atomic beam hole is opened on the furnace body of the atomic furnace, a collimator is arranged outside the atomic beam hole, and the atomic furnace emits an atomic beam through the collimator; keep the power of the laser constant to generate a constant laser, and make the generated laser act on the atomic beam to generate a measurable fluorescence signal; change the power of the atomic furnace and perform several measurements, measure the temperature of the atomic furnace through the temperature sensing device, and measure the fluorescence signal intensity information at this temperature through a photoelectric sensor, and fit the obtained atomic furnace temperature information and fluorescence signal intensity information for several times to obtain the corresponding relationship curve between the atomic furnace temperature and the fluorescence signal intensity;

[0008] The change in the fluorescence signal intensity is detected in real time by a photoelectric sensor. According to the corresponding relationship curve between the temperature and the fluorescence signal intensity, a feedback signal of the heating power of the atomic furnace is generated, and this feedback signal is input into the temperature locking loop to adjust the heating power of the atomic furnace in real time, thereby realizing the locking control of the atomic furnace temperature.

[0009] The beneficial effects produced by adopting the above technical solution are as follows: In the temperature sensing device of the present invention, the copper sleeve structure is adopted to make the thermistor fit more closely with the atomic furnace, so as to better reflect the temperature of the atomic furnace and make the temperature measurement more accurate; in the method, fluorescence is generated by the interaction of laser and atomic beam, the change in fluorescence intensity is detected by a photoelectric sensor, and the fluorescence intensity information is fed back to the temperature control loop in combination with the temperature-fluorescence signal intensity curve to realize temperature locking, which can lock the temperature more accurately, and thus can measure and control the atomic furnace temperature more precisely. Brief Description of the Drawings

[0010] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

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

[0012] Figure 2 is an assembly drawing of the temperature sensing device and the atomic furnace in an embodiment of the present invention;

[0013] Figure 3 is a schematic structural diagram after the temperature sensing device and the atomic furnace are assembled in an embodiment of the present invention;

[0014] Figure 4 is the overall flowchart of the method in an embodiment of the present invention;

[0015] Figure 5 is the measurement principle block diagram of the method in an embodiment of the present invention;

[0016] Figure 6 is a relationship curve graph of the atomic furnace temperature and the atomic beam intensity in the method in an embodiment of the present invention;

[0017] Figure 7 is a relationship curve graph of the atomic furnace temperature and the fluorescence signal intensity in the method in an embodiment of the present invention;

[0018] Wherein: 1. Thermistor; 1-1. Resistance body; 1-2. First pin; 1-3. Second pin; 2. Metal sleeve; 3. Furnace body; 4. Fixed clamp; 5. Temperature sensing device; 6. Collimator. Detailed Description of the Embodiment

[0019] The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0020] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the spirit of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0021] As Figure 1 - Figure 2 shown, an atomic furnace temperature sensing device is disclosed in an embodiment of the present invention, including a thermistor 1. The thermistor 1 includes a resistor body 1-1 and a first lead 1-2 and a second lead 1-3 connected to both ends of the resistor body 1-1.

[0022] Since the thermistor cannot truly measure the temperature inside the atomic furnace but only adheres to its outer wall and indirectly measures its temperature, the temperature measured by the thermistor is between the ambient temperature and the atomic furnace temperature, that is:

[0023] T 热敏 = k 1 T 原子炉 + k 2 T 环境 (1)

[0024] wherein, k 1 and k 2 are two fixed coefficients and satisfy k 1 + k 2 = 1. In the scheme of using the thermistor to lock the atomic furnace temperature, it is considered that k 2 = 0, then the thermistor represents the atomic furnace temperature and is independent of the ambient temperature. The actual situation is that k 2 ≠ 0, because the atomic furnace cannot completely achieve thermal insulation from the environment and there is heat conduction and radiation. Further, it can be deduced that:

[0025]

[0026] When the ambient temperature changes, even if the temperature measured by the thermistor remains unchanged, the atomic furnace temperature will change.

[0027] To solve the above problems, the present invention proposes a new thermistor fixing method to reduce k 2, and provided a new atomic furnace temperature locking scheme to further reduce the influence of ambient temperature on furnace temperature locking.

[0028] The new fixed structure of the thermistor is as follows: The measuring device further includes a metal sleeve 2. Preferably, the metal sleeve 2 can be 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 extends out of the metal sleeve 2 to form a bent portion, and the bent portion is in contact with the outer wall of the metal sleeve 2; a part of the resistor body 1-1 is located inside the metal sleeve 2 or the resistor body 1-1 is located outside the metal sleeve 2. The metal sleeve 2 is used to directly contact the furnace body 3 of the atomic furnace, and the furnace body 3 of the atomic furnace is an oxygen-free copper furnace body. In addition, further, the measuring device may further include a fixing clamp 4, and the fixing clamp 4 is used to fix the second pin 1-3.

[0029] In the new thermistor fixing method, to ensure the close fit of the thermistor and the atomic furnace, one end of the thermistor is sleeved with an oxygen-free copper sleeve, and then the pin of the thermistor extending out of the oxygen-free copper sleeve is bent to hook the oxygen-free copper sleeve, and then the whole is implanted into the reserved hole of the atomic furnace. Figure 2 Shows the assembly drawing of the atomic furnace and the thermistor. During the implantation process, due to the deformation of the thermistor pins and the copper sleeve, the metal parts are squeezed against each other to form a good conductor of heat, thereby reducing k in Equation 1 2 , reducing the influence of ambient temperature on furnace temperature measurement. Since the implantation process involves deformation and the implantation resistance is large, a corresponding metal outer sleeve is required for cooperation. Fix the metal outer sleeve to the outer end of the thermistor and tap the metal outer sleeve, and the implantation can be completed without damaging the thermistor and the atomic furnace. Figure 3 Shows the atomic furnace and the thermistor after being fixed.

[0030] In order to be able to measure and control the atomic furnace temperature more accurately, as Figure 4 shown, the present invention also discloses an atomic furnace temperature locking method, and its measurement principle is as Figure 5 shown, including the following steps:

[0031] S1: Under a stable ambient temperature, use the temperature sensing device 5 to measure the temperature information of the atomic furnace;

[0032] S2: There is an atomic beam hole on the reactor vessel 3 of the atomic furnace. A collimator 6 is arranged outside the atomic beam hole. The atomic furnace emits an atomic beam outward through the collimator 6; keep the power of the laser constant to generate a constant laser, and make the generated laser act on the atomic beam to generate a measurable fluorescence signal; change the power of the atomic furnace and conduct several measurements. Measure the temperature of the atomic furnace through the temperature sensing device 5, and measure the fluorescence signal intensity information at this temperature through a photoelectric sensor. Fit the obtained atomic furnace temperature information and fluorescence signal intensity information for several times to obtain the corresponding relationship curve between the temperature of the atomic furnace and the fluorescence signal intensity.

[0033] In the new temperature locking method, fluorescence signals are generated through the interaction between the laser and the atomic beam, and the temperature of the atomic furnace is locked by detecting the change in fluorescence intensity. The locking process of this scheme is not affected by the ambient temperature.

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

[0035]

[0036] (unit: Torr, 1 Torr = 133.32 Pa). Then calculate the atomic density n 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, a collimator composed of a large number of micropores needs to be added. Because of the existence of the collimator, most atoms will be bounced back to the cesium furnace instead of being ejected. In the presence of the collimator, the beam intensity ejected by the atomic furnace is given by the following expression (i at number of atoms ejected per unit time):

[0039]

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

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

[0042]

[0043] where Γ is the natural linewidth, Δ is the detuning (which is zero when using and optically detecting atoms), I is the light intensity, and I sat is the saturation light intensity, satisfying:

[0044]

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

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

[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 region (considering divergence), and v is the average atomic velocity.

[0050] Through means such as optical simulation, the proportion γ of these photons entering the photoelectric sensor can be obtained. Combining the photon-to-current conversion efficiency β of the photoelectric sensor and the current-to-voltage amplification factor α, the fluorescence signal intensity U 1 (in volts) and the relationship with the atomic beam intensity can be obtained:

[0051]

[0052] where e is the electron charge.

[0053] It can be seen that the read fluorescence signal U 1 is proportional to the atomic beam intensity I at , and further the functional relationship between the fluorescence signal U and the atomic furnace temperature T can be obtained. The actual fluorescence signal U = U 1 + U 2 , where U 2 is the contribution of spatial scattering entering the photoelectric sensor. Satisfying:

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

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

[0056] Overall, it can be seen that the atomic furnace temperature is positively correlated with the fluorescence signal intensity, and the functional relationship is independent of the ambient temperature:

[0057]

[0058] Figure 7 The relevant curves are given. As an example, take: α = 20k, β = 50%, γ = 50%, μ = 10%, D = 300mm, R = 3mm, Γ = 5MHz, I = 70W / m 2 , I sat = 110W / m 2 .

[0059] In actual situations, the confirmation of the above parameters is complex. Using a calibration method can more efficiently determine the relationship between the fluorescence signal and the atomic furnace temperature. Through simplification, a simpler expression form 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 respectively. It can be seen from the above results that measuring at least two points can complete the calibration of the functional relationship, that is, determine A and B.

[0062] Since there is a direct functional relationship between the fluorescence signal and the atomic furnace temperature, the real-time measurement of the atomic fluorescence intensity can provide real-time feedback control of the temperature. And because the functional relationship is independent of the ambient temperature, it can operate stably under changing ambient temperatures.

[0063] S3: Real-time detect the change in the fluorescence signal intensity through a photoelectric sensor. According to the corresponding relationship curve between the temperature and the fluorescence signal intensity, generate a feedback signal of the heating power of the atomic furnace, and input this feedback signal into the temperature locking loop to adjust the heating power of the atomic furnace in real time, thereby realizing the locking control of the atomic furnace temperature.

[0064] In summary, the method described in this application measures the temperature using a thermistor under a stable ambient temperature. After the laser power is locked, the laser interacts with the atomic beam and the fluorescence signal intensity is measured to obtain the corresponding relationship between the temperature and the fluorescence signal intensity. The temperature at this time is the temperature measured by the thermistor. However, since the ambient temperature is constant, the corresponding atomic furnace temperature is also a fixed value. That is, although there is a deviation between the atomic furnace temperature and the temperature measured by the thermistor (Equation (2)), this deviation is a constant value. In subsequent lockings, it no longer depends on the temperature measured by the thermistor, so this constant deviation will not change during the locking process.

[0065] After that, 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 ambient temperature, the influence brought about by the change in ambient temperature does not need to be considered during the operation of the system, that is, the atomic furnace temperature locking of this patent is achieved.

Claims

1. A temperature sensing device for a nuclear reactor, comprising a thermistor (1), wherein the thermistor (1) comprises a resistor body (1-1) and a first pin (1-2) and a second pin (1-3) connected to two ends of the resistor body (1-1), characterized in that: The measuring device also includes 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 bent portion, the bent portion is in contact with the outer wall of the metal sleeve (2), the resistor body (1-1) is partially located in the metal sleeve (2) or the resistor body (1-1) is located outside the metal sleeve (2), and the metal sleeve (2) is used to directly contact the furnace body (3) of the atomic reactor.

2. The atomic furnace temperature sensing device according to claim 1, characterized in that: The metal sleeve (2) is an oxygen-free copper sleeve.

3. The atomic reactor temperature sensing device according to claim 1, characterized in that: The measuring device also comprises a fixing fixture (4), and the fixing fixture (4) is used to fix the second pin (1-3).

4. A method for locking the temperature of a nuclear furnace, characterized in that The steps include: Under a stable ambient temperature, using a temperature sensing device (5) as claimed in any one of claims 1 to 3 to measure the temperature information of the nuclear reactor; An atomic beam hole is provided 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 outward through the collimator (6); the power of the laser is kept constant so that it generates constant laser light, and the generated laser light interacts with the atomic beam to generate a measurable fluorescence signal; the power of the atomic furnace is changed and several measurements are performed, the temperature of the atomic furnace is measured by the temperature sensing device (5), and the fluorescence signal intensity information at the temperature is measured by a photoelectric sensor, and the obtained atomic furnace temperature information and fluorescence signal intensity information are fitted to obtain a corresponding relationship curve between the temperature of the atomic furnace and the fluorescence signal intensity; The change of fluorescence signal intensity is detected in real time by a photoelectric sensor, and the temperature of the atomic furnace is calculated according to the corresponding relationship curve between the temperature and the fluorescence signal intensity, and a feedback signal of the heating power of the atomic furnace is generated. The feedback signal is input into a temperature locking loop for real-time adjustment of the heating power of the atomic furnace, thereby realizing locking control of the atomic furnace temperature.

5. The method for locking the temperature of a nuclear reactor as claimed in claim 4, characterized in that: The temperature of the atomic furnace is positively correlated with the intensity of the fluorescence signal.

6. The method for locking the temperature of a nuclear reactor as claimed in claim 4, characterized in that: The formula of the corresponding relationship curve between the temperature of the atomic furnace and the fluorescence signal intensity is: Among them, P v is the atomic saturated vapor pressure, U is the fluorescence signal intensity, and T is the atomic furnace temperature. At least two sets of atomic furnace temperature information and fluorescence signal intensity information are used to calibrate the unknown coefficients A and B to obtain the corresponding relationship curve.

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