Cryogenic Thermometers Research Articles

Thickness Measurement and Sensitivity of Copper/Nickel Electroplating Results of Electrolyte Solution Temperature Variation

Currently, cryogenic thermometers are needed and one of the uses of cryogenic thermometers is to measure the temperature of food preservation flasks. Research has been conducted on the manufacture of cryogenic thermometers derived from Cu/Ni coils by electroplating process with temperature variation treatment of electrolyte solution. The purpose of this study is to determine the effect of electrolyte solution temperature variation treatment on Ni thickness and Cu/Ni sensitivity as a low-temperature sensor. Electroplating was carried out with electrolyte temperature parameters of 30˚C-70˚C, electrode distance of 4 cm, voltage of 4.5 volts, and coating time of 4 minutes. The electrolyte solution was a mixture of NiSO4 260 g, NiCl2 60 g, H3BO3 40 g, and Aquades 1000 mL. Based on the results of the study, a remarkable condition was obtained on the thickness of Ni; namely, at 40 ˚C, the thickness increased to 1.08 mm. In addition, the best temperature can produce the greatest sensitivity value in Cu/Ni coil electroplating, namely at 50 ˚C.

Processing calibration data of low-temperature thermometer based on clustering algorithm.

The scarcity of cryogenic thermometers often stems from their high cost and lengthy lead times for calibration. Establishing an in-lab temperature calibration system is necessary to quickly make use of uncalibrated sensors or self-made sensors. This paper introduces a straightforward and high-accuracy thermometer calibration system. By employing copper screws as thermal links between the sensor platform and the cryogen-free refrigerator, temperature oscillation on the sensor platform is suppressed to a few millikelvins. In addition, this paper presents a data processing model based on clustering algorithms. These algorithms sort and group data based on distance, which is similar to human visual judgment of data. This paper discusses the parameter optimization process of the clustering algorithm to interpret the automated data process. The cryogenic temperature sensors calibrated by this system exhibited high accuracy, with relative errors of less than 1% compared to standard thermometers. Moreover, automatically processing calibration data from two uncalibrated thermometers takes just over 10min, highlighting the effectiveness of this calibration system.

Th4+ Co‐doped YF3 : Yb3+, Er3+ Nanostructures for Enhanced Visible and NIR‐II Emissions and Potential Application as Cryogenic Thermometer

AbstractRemarkable enhancement in green and red upconversion (UC) emissions by 124 and 88 %, respectively was achieved whereas down‐conversion (DC) luminescence in NIR‐II region (~1540 nm) was improved by 20 % in Th4+ co‐doped YF3 : Yb3+,Er3+ nanocrystalline particles. The same is ascribed to lowering of symmetry via formation of asymmetric Er−F bonds and less symmetric Y3+ sites due to distortions on Th4+ co‐doping. Benefiting from the distinct temperature response of stark sublevels of the 4S3/2 and 4F9/2 states, we have proposed a strategy for luminescence intensity ratios (LIR) based thermometry involving thermally coupled (TCL) stark sub‐levels. This can be promising in more accurate temperature read‐out at cryogenic temperatures (~ −193 °C). Using the same, high Sa and Sr values of 0.0139 K−1 (80 K) and 0.682 % K−1(80 K) were obtained for 4S3/2 (1)/4S3/2 (2)→4I15/2 transitions. Higher Sa and Sr values of 0.226 K−1 (80 K) and 2.627 %K−1(80 K) were obtained for 4F9/2 (1)/4F9/2 (2)→4I15/2 transitions. The high sensitivity values were obtained than that reported for the YF3 host. We believe this work with improved UC luminescence on Th4+ addition will be boon to cryogenic temperature‐sensing.

Effective ratiometric optical thermometry based on inverse temperature dependent dual near infrared emission of Cr3+ doped BaAl4Sb2O12 phosphor

The device of reliable non-contact ratiometric optical thermometry technique gradually became a cutting-edge research pot over decades due to its intriguing features of rapid response, high accuracy and simple operation. In which, Boltzmann-based optical thermometry has attracted widespread attention for its exceptional reliability. Here in, we put forward an effective ratiometric optical thermometry based on the highly sensitive and effective Boltzmann-based 2E→4A2/4T2→4A2 emission ratio of BaAl3.9Sb2O12:0.1Cr3+. The phosphor shows dual near-infrared luminescence lines at 698 nm and 710 nm (2E→4A2) and the luminescence band near 750 nm (4T2→4A2). With the temperature elevating from 170 to 470 K, the emission intensity of luminescence lines undergoes continuous enhancement and possess excellent anti-thermal quenching property (3.5-fold at 470 K, compared to 170 K). In contrast, the emission intensity of luminescence band shows a monotonic decline trend. The luminescence intensity ratio shows a good linear relationship in the Arrhenius diagram, and the relative sensitivity reaches 2.08 % K−1 at 170 K, which corroborates the BaAl3.9Sb2O12:0.1Cr3+ has the potential as the optical cryogenic thermometer. In the end, the work provides some insights into the development of novel Cr3+-doped thermometry materials based on the 2E and 4T2 energy level transitions in intermediate crystal field environments.

A new highly sensitive cryogenic luminescent MOF thermometer built with pyromellitic acid

Design of a new highly sensitive cryogenic luminescent thermometer based on a mixed Eu/Tb MOF.

Strong electron–phonon coupling of Cr3+ ion provides an opportunity for superior sensitivity cryogenic sensing

Nowadays, optical temperature measurement is becoming a reliable and advanced technology. Most of optical temperature sensing materials have been reported in the first biological temperature region or even higher. However, cryogenic optical sensing materials seem to be ignored. Here, Cr3+-doped SrGa12O19 is reported, exhibiting a obvious sharp peak at 696 nm (2E→4A2) and near-infrared emission at 750 nm (4T2→4A2) at 77 K. As the temperature increases, the transition of 2E→4A2 is suppressed and the emission of 4T2 is broadened due to the increasing electron–phonon coupling effect. This feature provides an opportunity to obtain the obvious discrepancy of fluorescence intensity, and further realize the superior cryogenic sensing performance based fluorescence intensity ratio (FIR) method with the maximum absolute sensitivity (Sa) of 0.0085 K−1 and relative sensitivity (Sr) of 2.62 %·K−1 at 77 K. The value of Sr is 138.6 % higher than that of CaHfO3:Cr3+ system and the temperature uncertainty (δT) is one order of magnitude lower than the most popular ruby Al2O3:Cr3+, showing superior cryogenic sensing ability. This work not only exhibits a novel cryogenic sensing material but also provides a train of thought for designing cryogenic thermometer.

On-chip heating effects in electronic measurements at cryogenic temperatures

Heating is a major concern for electrical measurements at cryogenic temperatures. In this study, the statics and dynamics of heating effects induced on a Si/SiO2 chip by the application of DC and AC power to an on-chip heating element are measured using on-chip cryogenic thermometers. It is found that large on chip temperatures, ∼ 100 mK above cryostat temperature, and large on-chip thermal gradients, 100s of mK over ∼ 10 μm distance, are generated at relatively small (∼ 0.1 μW) input powers. As expected, the heating effects are larger at lower cryostat temperatures. With applied AC voltages, it is found that the average temperatures generated are similar in magnitude to the DC voltages, but the temperature gradients are smaller. The average temperatures reached on the surface of the chip increase with increasing frequency. At 5 Hz frequency, the thermal dynamics are too slow to allow temperature oscillations following the input power, instead resulting in a steady state temperature increase.

Thermochromic photoluminescent 3D printed polymeric devices based on copper-iodide clusters

In this work, optically active devices are fabricated by Digital Light Processing (DLP) 3D printing technology employing copper-iodide photoluminescent clusters as smart dyes in the photocurable formulation. These compounds are easy to synthesize, low cost and possess large stoke shift, thermochromic and rigidochromic properties, which make them particularly appealing for the development of optical devices. By dispersing such compounds in photocurable formulations, the same properties are transferred to polymeric materials, enabling the production of a large range of devices. Absorbing in the UV range and emitting in the visible range, those clusters show twofold advantages: on the one hand, competing with the photoinitiator for the light absorption, they allow a better control of the photopolymerization process, enabling the fabrication of precise structures; on the other hand, these possess aesthetic properties, being transparent and then emitting light when irradiated. At last, functional structures, such as 3D printed polymeric waveguides (PWGs) and downshifting devices, are fabricated and investigated but even other uses can be envisaged, such as cryogenic optical thermometers.

Focused ion beam deposited carbon-platinum nanowires for cryogenic resistive thermometry

Abstract The study of thermal effects, both classical and quantum, at cryogenic temperatures requires the use of on-chip, local, high-sensitivity thermometry. Carbon-platinum composites fabricated using focused ion beam (FIB) assisted deposition form a granular structure which is shown in this study to be uniquely suited for this application. Carbon-platinum thermometers deposited using a 24 pA ion beam current have high sensitivities below 1 K, comparable to the best cryogenic thermometers. In addition, these thermometers can be accurately placed to within 10s of nanometers on the chip using a mask-free process. They also have a weak magnetic field dependence, 3% change in resistance with applied magnetic fields from 0 to 8 T. Finally, these thermometers are integrable into a variety of nanoscale devices due to the existing wide spread use of FIB.

A non-local cryogenic thermometer based on Coulomb-coupled systems

We investigate a quadruple quantum dot setup that can be employed to sense the temperature of an electrically isolated remote target reservoir. Such a setup was conceived earlier by Sánchez et al. [New J. Phys. 19, 113040 (2017)] as non-local thermodynamic engine and relies on the electrostatic interaction between Coulomb-coupled quantum dots. The conjugation of Coulomb-coupling and energy-filtering results in an overall change in conductance with remote reservoir temperature. The performance of the thermometer is then theoretically investigated using density matrix formulation, and it is demonstrated that the quadruple quantum dot design ensures a superior temperature sensitivity and noise robustness compared to a simple thermometer consisting of two Coulomb-coupled quantum dots. In the end, we investigate the regime of operation and comment on the ground state configuration for optimal performance of the thermometer. The setup investigated in this paper can be employed to construct highly efficient non-local cryogenic thermometers.

Nongalvanic Calibration and Operation of a Quantum Dot Thermometer

A cryogenic quantum dot thermometer is calibrated and operated using only a single non-galvanic gate connection. The thermometer is probed with radio-frequency reflectometry and calibrated by fitting a physical model to the phase of the reflected radio-frequency signal taken at temperatures across a small range. Thermometry of the source and drain reservoirs of the dot is then performed by fitting the calibrated physical model to new phase data. The thermometer can operate at the transition between thermally broadened and lifetime broadened regimes, and outside the temperatures used in calibration. Electron thermometry was performed at temperatures between $3.0\,\mathrm{K}$ and $1.0\,\mathrm{K}$, in both a $1\,\mathrm{K}$ cryostat and a dilution refrigerator. The experimental setup allows fast electron temperature readout with a sensitivity of $4.0\pm0.3 \, \mathrm{mK}/\sqrt{\mathrm{Hz}}$, at Kelvin temperatures. The non-galvanic calibration process gives a readout of physical parameters, such as the quantum dot lever arm. The demodulator used for reflectometry readout is readily available and very affordable.

Cryogenic Diode Thermometer Insensitive Completely to Magnetic Fields Up to 1 T

The article presents investigation results concerning silicon p-n junction diodes with heightened diode base doping level up to a critical value for the insulator-metal transition. Accent is made on application of such the diodes as temperature sensors in cryogenic region and in the presence of magnetic fields, i.e. under conditions when available commercial silicon diode temperature sensors become inapplicable. The reason is a freezing-out of the free current carriers in their lightly doped bases. In this case the base conduction becomes hopping with large magnetoresistance, and an impact ionization of the frozen-out carriers in the electric field results in electrical instability (hysteretic phenomena in the current-voltage characteristics). It is shown that the diodes investigated are free of the electrical instabilities inherent in the commercial diodes, and can operate with much lower the sensor working currents. The lower the operating current, the smaller is the measurement error connected with magnetic-field influence. At the operating currents of 10 and 1 μA, the sensor proves to be insensitive completely to magnetic fields up to 1 T.

Focused ion beam deposited carbon-platinum nanowires for cryogenic resistive thermometry

The study of thermal effects, both classical and quantum, at cryogenic temperatures requires the use of on-chip, local, high-sensitivity thermometry. Carbon-platinum composites fabricated using focused ion beam (FIB) assisted deposition form a granular structure which is shown in this study to be uniquely suited for this application. Carbon-platinum thermometers deposited using a 24 pA ion beam current have high sensitivities below 1 K, comparable to the best cryogenic thermometers. In addition, these thermometers can be accurately placed to within 10s of nanometers on the chip using a mask-free process. They also have a weak magnetic field dependence, < 3% change in resistance with applied magnetic fields from 0 to 8 T. Finally, these thermometers are integrable into a variety of nanoscale devices due to the existing wide spread use of FIB.

Pushing the Limit of Boltzmann Distribution in Cr3+-Doped CaHfO3 for Cryogenic Thermometry.

Luminescence Boltzmann thermometry is one of the most reliable techniques used to locally probe temperature in a contactless mode. However, to date, there is no report on cryogenic thermometers based on the highly sensitive and reliable Boltzmann-based 4T2 → 4A2/2E → 4A2 emission ratio of Cr3+. On the basis of structural information of the local HfO6 octahedral site we demonstrated the potential of the CaHfO3:Cr3+ system by combining deep theoretical and experimental investigation. The material exhibits simultaneous emission from both the 2E and 4T2 excited states, following the Boltzmann law in a cryogenic temperature range of 40-150 K. The promising thermometric performance corroborates the potential of CaHfO3:Cr3+ as a Boltzmann cryothermometer, being characterized by a high relative sensitivity (∼ 2%·K-1 at 40 K) and exceptional thermal resolution (0.045-0.77 K in the 40-150 K range). Moreover, by exploiting the flexibility of the 4T2-2E energy gap controlled by the crystal field of the local octahedral site, the design proposed herein could be expanded to develop new Cr3+-doped cryogenic thermometers.

Криогенные термометры сопротивления на основе пленок Ge–InP. Технология и конструирование в электронной аппаратуре

Despite the large number of scientific articles devoted to the development of cryogenic resistance thermometers, not many of these thermometers are mass-produced. As is know, semiconductor resistive temperature sensors have low magnetoresistance and high resistance to radiation. The purpose of this work was to manufacture thin (170—190 nm) Ge films on semi-insulating InP substrates, which can be used to create cryogenic resistance thermometers with high temperature sensitivity and relatively low sensitivity to magnetic field that can operate in the 1.5—400 К temperature range. Films of Ge on InP (100) can be used to produce cryogenic resistance thermometers. They have good thermal sensitivity and relatively low magnetoresistance. The films were produced by thermal evaporation of Ge in vacuum (2•10-4 Pa) on semi-insulating InP (100) substrates. The temperature of the InP substrate during film deposition was 310°C, the deposition rate was also constant during sputtering, but varied in the range of 0.03 to 0.06 nm/s for different films. Ge films were p-type conductivity with a resistivity of 0.2—0.3 Ω•cm, hole concentration (3—5)•1018 cm–3 and Hall mobility 6.5—7.5 сm2/(V•s) at room temperature. The quality of the Ge–InP heterostructure was determined by high-resolution X-ray diffraction on a Philips MRD diffractometer. The nanomorphology of the surface of Ge films was studied using the NanoScope IIIa atomic force microscope. The crystal structure of the films is amorphous or polycrystalline with a low level of structural perfection. The effective value of the surface roughness is from 2.25 to 2.60 nm. The obtained resistance values at different temperature in the range of 2—25 K were described by exponential dependence. Corrections in temperature measurement are 5% in a magnetic field of 11 T at a temperature of 4.2 K and 14% in a magnetic field of 14 T at a temperature of 2.2 K. The research results indicate that the obtained films can be used to measure cryogenic temperatures in magnetic fields of up to 14 T.

Multiresponsive UV-One-Photon Absorption, Near-Infrared-Two-Photon Absorption, and X/γ-Photoelectric Absorption Luminescence in One [Cu4I4] Compound.

A new Cu4I4-cluster-based compound is constructed to show multifaceted photoluminescent attributes: (1) ultraviolet (UV)-excited thermo-, mechano-, and rigido-chromic phosphorescence by the OPA (one-photon absorption) pathway, due to the interchanging emissions from cluster-centered (3CC) and halide-to-ligand charge-transfer (3XLCT) excited triplet states, (2) the ability to convert X/γ-ray and near-infrared (NIR) radiation to visible-light emission, in which the heavy Cu4I4 cores serve as the efficient X/γ-PEA (photoelectric absorption) or NIR-TPA (two-photon absorption) trapper and convertor to photons in the visible spectrum from the same emissive triplet states as those produced by UV excitation. This all-in-one compound affords a highly integrated nanolab for understanding and exploiting a wide range of photophysical phenomena simultaneously and is further fabricated into fiber-coupled long-range, in situ cryogenic thermometer and poly(methyl methacrylate) (PMMA)-embedded monolith gel, providing access to advanced applications in multifunctional optical materials and devices.

Nanokelvin DC and AC Meissner-transition-edge temperature detectors.

Based upon a superconducting transition edge sensor (TES), the Meissner-TES is a relatively new type of high resolution cryogenic thermometer which employs the magnetic transition of a superconductor to measure temperature. We have improved the signal-to-noise for DC sensing by a factor of 30 compared to our prior effort and developed a new AC mode which uses an oscillating magnetic field and a lock-in technique with much lower magnetic noise than the DC mode. The thermometer was tuned in situ over a range of operating temperatures 10-50 times larger than the transition width of the superconductor, using an applied persistent magnetic field. The DC mode can have sensitivity better than 1 nK for 100 s averaging, and the AC mode has sensitivity better than 120 nK for very small applied magnetic fields near 14 nT and 100 s averaging. The Meissner-TES can be applied to high resolution temperature control, high sensitivity infrared sensing, optical power scale realization, and the study of temperature-dependent phase transitions.

High level gamma radiation effects on Cernox™ cryogenic temperature sensors

Cryogenic temperature sensors are used in high energy particle colliders to monitor the temperatures of superconducting magnets, superconducting RF cavities, and cryogen infrastructure. While not intentional, these components are irradiated by leakage radiation during operation of the collider. A common type of cryogenic thermometer used in these applications is the Cernox™ resistance thermometer (CxRT) manufactured by Lake Shore Cryotronics, Inc. This work examines the radiation-induced calibration offsets on CxRT models CX-1050-SD-HT and CX-1080-SD-HT resulting from exposure to very high levels of gamma radiation. Samples from two different wafers of each of the two models tested were subjected to a gamma radiation dose ranging from 10 kGy to 5 MGy. Data were analysed in terms of the temperature-equivalent resistance change between pre- and post-irradiation calibrations. The data show that the resistance of these devices decreased following irradiation resulting in positive temperature offsets across the 1.4 K to 330 K temperature range. Variations in response were observed between wafers of the same CxRT model. Overall, the offsets increased with increasing temperature and increasing gamma radiation dose. At 1.8 K, the average offset increased from 0 mK to +13 mK as total dose increased from 10 kGy to 5 MGy. At 4.2 K, the average offset increased from +4 mK to +33 mK as total dose increased from 10 kGy to 5 MGy. Equivalent temperature offset data are presented over the 1.4 K to 330 K temperature range by CxRT model, wafer, and total gamma dose.

Development of an experimental variable temperature set-up for a temperature range from 2.2 K to 325 K for cost-effective temperature sensor calibration

A prototype of a variable temperature insert has been developed in-house as a cryogenic thermometer calibration facility. It was commissioned in fulfilment of the very stringent requirements of the temperature control of the cryogenic system. The calibration facility is designed for calibrating industrial cryogenic thermometers that include a temperature sensor and the wires heat-intercept in the 2.2 K–325 K temperature range. The isothermal section of the calibration block onto which the thermometers are mounted is weakly linked with the temperature control zone mounted with cooling capillary coil and cryogenic heater. The connecting wires of the thermometer are thermally anchored with the support of the temperature insert. The calibration procedure begins once the temperature of the support is stabilized. Homogeneity of the calibration block’s temperature is established both by simulation and by cross-comparison of two calibrated sensors. The absolute uncertainty present in temperature measurement is calculated and found comparable with the measured uncertainty at different temperature points. Measured data is presented in comparison to the standard thermometers at fixed points and it is possible to infer that the absolute accuracy achieved is better than ±0.5% of the reading in comparison to the fixed point temperature. The design and development of simpler, low cost equipment, and approach to analysis of the calibration results are discussed further in this paper, so that it can be easily devised by other researchers.

Ratiometric mixed Eu–Tb metal–organic framework as a new cryogenic luminescent thermometer

The first example of a dual-emitting luminescent thermometer based on lanthanide isophthalate exhibiting a maximum relative sensitivity of 3.26% K−1, a temperature uncertainty of 0.07 K at 35.5 K, and a repeatability &gt;99.9% between 12 and 230 K.