Superconductivity Transition Dependence of the Thermal Crosstalk in YBa2Cu3O7-x Edge-Transition Bolometer Arrays

The effect of the superconductivity transition on the thermal crosstalk in YBa2Cu3O7-x, edge-transition bolometer arrays is investigated for DC to midrange modulation frequency infrared radiation. The bolometers; in the arrays were designed with various distances on SrTiO3 (100) substrates. We have observed a change in the thermal crosstalk between neighbor devices through the superconductivity transition temperature range. Superconductivity transition dependence of the thermal coupling between the devices was measured by utilizing the thermal conductance measurement methods developed for the bulk material. The knee points in the magnitude of the response versus modulation frequency curves of the devices were also determined by illuminating one of the bolometers in the arrays and measuring the response of the neighbor devices. By using the knee frequency and the distance between the bolometers, the modulation frequency criterion for crosstalk-free response at the transition region in various array structures is found and the results of the thermal coupling measurements are further studied and presented here

Hybrid Synaptic Structure for Spiking Neural Network Realization

Neural networks and neuromorphic computing play pivotal roles in deep learning and machine vision. Due to their dissipative nature and inherent limitations, traditional semiconductor-based circuits face challenges in realizing ultra-fast and low-power neural networks. However, the spiking behavior characteristic of single flux quantum (SFQ) circuits positions them as promising candidates for spiking neural networks (SNNs). Our previous work showcased a JJ-Soma design capable of operating at tens of gigahertz while consuming only a fraction of the power compared to traditional circuits, as documented in [1]. This paper introduces a compact SFQ-based synapse design that applies positive and negative weighted inputs to the JJ-Soma. Using an RSFQ synapse empowers us to replicate the functionality of a biological neuron, a crucial step in realizing a complete SNN. The JJ-Synapse can operate at ultra-high frequencies, exhibits orders of magnitude lower power consumption than CMOS counterparts, and can be conveniently fabricated using commercial Nb processes. Furthermore, the network's flexibility enables modifications by incorporating cryo-CMOS circuits for weight value adjustments. In our endeavor, we have successfully designed, fabricated, and partially tested the JJ-Synapse within our cryocooler system. Integration with the JJ-Soma further facilitates the realization of a high-speed inference SNN.Comment: 7 pages, 10 figure

İnvestigation, modeling, and applications feasibility of the thermal crosstalk in high Tc transition edge bolometer arrays

Cataloged from PDF version of article.So far, the high Tc transition edge bolometer (TEB) devices are mostly used as single pixel detectors. Recently, there are a number of groups working on the 2-4 pixel array applications of the high Tc TEB. Though the target spectrum of the TEB is far IR and mm-waves, we are using a near IR laser source in our investigation due to practical reasons since the response analysis is similar. We have designed and implemented 4-pixel Y Ba2Cu3O7−δ (YBCO) edge transition bolometer arrays. The crosstalk study was made possible through the illumination of the sense-devices and measuring the voltage response of the blocked read-out device in the same array. This was done using a silver coated shadow mask. In order to prevent thermal artifacts created by the mask, the mask was made in free standing configuration on top of the devices. The devices were made of 200 nm and 400 nm thick pulsed laser deposited YBCO films on SrT iO3 and LaAl2O3 substrate materials. In this thesis, we made the qualitative investigation of the dependence of the thermal crosstalk on the various device parameters such as the substrate material, device layout, YBCO film thickness, operating temperature, and modulation frequency. Then, based on the experimental results, we proposed an analytical thermal model. We proposed two models: i) Basic model, which takes into account only the lateral heat diffusion in the substrate for quick design purposes ii)Analytical model, which takes into account the lateral heat diffusion, vertical heat diffusion, and the effect of the leaking laser radiation through the shadow mask, for detailed design purposes and verifying the qualitative analysis. Finally, we proposed and verified possible applications of the thermal crosstalk in TEB arrays. One proposed application of the crosstalk is the electrical free read-out of the sense pixels by utilization of the unique dependence of the magnitude and phase of the response on the thermal crosstalk between bolometer pixels in an array. The qualitative investigation made in this study is the most detailed investigation about the bolometer arrays and the proposed analytical model is the strongest among the reported ones so far in terms of fitting the experimental results, explaining the effects of the various parameters, and designing TEB arrays. The proposed crosstalk based read-out method is expected to decrease the read-out circuitry for possible TEB based applications. Since multilayer process is difficult to make in high Tc superconductors, decreasing the complexity of the read-out circuitry by half is even important and it is the first time that such a method is utilized including bolometer arrays made of different types of materials.Bozbey, AliPh.D

Synthesis and cytotoxicity studies on new pyrazolecontaining oxime ester derivatives

Purpose: To synthesize a series of new 1-(2-naphthyl)-2-(1H-pyrazol-1-yl)ethanone oxime ester derivatives (5-12) with potential anticancer properties, and to determine their cytotoxic effects in mouse fibroblast and human neuroblastoma cell lines. Methods: The title compounds were obtained through sodium salt reaction of 1-(naphthalene-2-yl)-2- (1H-pyrazol-1-yl)etanone oxime (4) with various acyl chlorides. The cytotoxic effects were evaluated by MTS colorimetric assay, while physicochemical descriptors were calculated using QikProp software. Results: Most of the compounds showed approximately 50 – 60 % inhibition against SH-SY5Y neuroblastoma cells at 100 μM. Of these, compound 7a was the most active combination with an IC50 value of 85.94 µM. The toxic effect of the compounds on mouse fibroblast cell line was insignificant (p < 0.05) even when the dose was increased. The calculated physicochemical properties of the compounds were within drug-like chemical space. Conclusion: The synthesized oxime ester derivatives with pyrazole ring exhibit selective toxicity to neuroblastoma cells without affecting healthy mouse fibroblast cells. The compounds proved to be druglike while their pharmacokinetic features were also encouraging, and were in line with in silico predictions

Superconductivity transition dependence of the thermal crosstalk in YBa 2Cu 3O 7-x edge-transition bolometer arrays

The effect of the superconductivity transition on the thermal crosstalk in YBa 2Cu 3O 7-x, edge-transition bolometer arrays is investigated for DC to midrange modulation frequency infrared radiation. The bolometers in the arrays were designed with various distances on SrTiO 3 (100) substrates. We have observed a change in the thermal crosstalk between neighbor devices through the superconductivity transition temperature range. Superconductivity transition dependence of the thermal coupling between the devices was measured by utilizing the thermal conductance measurement methods developed for the bulk material. The knee points in the magnitude of the response versus modulation frequency curves of the devices were also determined by illuminating one of the bolometers in the arrays and measuring the response of the neighbor devices. By using the knee frequency and the distance between the bolometers, the modulation frequency criterion for crosstalk-free response at the transition region in various array structures is found and the results of the thermal coupling measurements are further studied and presented here. © 2005 IEEE

Analytical modelling of the interpixel thermal crosstalk in superconducting edge-transition bolometer arrays

We present an analytical thermal model to explain the crosstalk in YBCO edge-transition bolometer arrays. The verification of the model was tested on sample array devices made of 200 and 400 nm YBCO films on LaAlO3 and SrTiO3 substrates. The model presented was able to explain the effects of the various physical parameters of the devices, such as the film thickness, operating temperature, and the device separation, which cause different response behaviours based on the variation of the related thermal crosstalk characteristics. In addition, the model is valid above the crosstalk-free modulation frequencies, where the effects of the thermal crosstalk on the response of the devices are negligible. © 2006 IOP Publishing Ltd

Electrical-contact-free readout of the response of superconductive bolometer arrays using thermal cross talk

We utilized and investigated the unique dependence of the magnitude and phase of the response on thermal cross talk between bolometer pixels in an array to measure the response of the devices through fewer monitoring devices. We show the feasibility of the proposed readout technique by use of two source pixels in an array, as the image-mapping devices, and one optically shielded pixel as the readout device. While the sensing pixels were electrical-contact free, the readout device was current biased in 4-probe current-bias configuration. Both the phase and the magnitude of the response due to the cross talk in the array were found to be strongly dependent on the modulation frequency and the distance between the sensing and the readout pixels. A series of measurements were designed to extract the response of each single-sensing pixel. By combining the measured data, the response of individual pixels could be extracted through the interpolation of the mapped responses. © 2006 Optical Society of America

Feasibility of electrical-contact free measurement of the response of superconductive bolometer arrays using the thermal crosstalk

We utilized and investigated the unique dependence of the magnitude and phase of the response on the thermal crosstalk between bolometer pixels in an array to measure the response of the devices through fewer monitoring devices. In this study, we show the feasibility of the proposed read-out technique by use of two source pixels in an array, as the image-mapping devices, and one optically shielded pixel as the read-out device. While the sense pixels were electrical-contact free, the read-out device was current biased in 4-probe current-bias configuration. Both the phase and magnitude of the response due to the crosstalk in the array were found to be strongly dependent on the modulation frequency and the distance between the sense and read-out pixels. A series of measurements were designed to extract the response of each single sense-pixel. By combining the measured data, the response of individual pixels could be extracted through the interpolation of the mapped responses. © 2006 IOP Publishing Ltd