Performance of Magnetic Penetration Thermometers for X-ray Astronomy

Nagler, Peter C.; Adams, J. S.; Balvin, M. A.; Bandler, S. R.; Denis, Kevin; Hsieh, Wen Ting; Kelly, Daniel P.; Porst, Jan‐Patrick; Sadleir, J. E.; Seidel, G. M.; Smith, S. J.; Stevenson, Thomas

doi:10.1007/s10909-012-0516-8

Cited by 9 publications

(8 citation statements)

References 9 publications

(8 reference statements)

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“…The total area of contact of these stems is just 0.1% of the area of the MoAu. The superconducting transition temperature was lower for this experiment and the temperature of operation of 35 mK is at the steepest part of the MPT transition curve for I b = 0.38 mA 14 . When x-rays are stopped in the absorber, i.e., when the whole energy of the x-ray was retained in the spectrometer following its absorption, the measured spectral resolution of Mn K α complex was 4.3 eV (FWHM).…”

Section: Methodsmentioning

confidence: 53%

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Athermal energy loss from x-rays deposited in thin superconducting films on solid substrates

et al. 2013

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When energy is deposited in a thin-film cryogenic detector, such as from the absorption of an x-ray, an important feature that determines the energy resolution is the amount of athermal energy that can be lost to the heat bath prior to the elementary excitation systems coming into thermal equilibrium. This form of energy loss will be position dependent and therefore can limit the detector energy resolution. An understanding of the physical processes that occur when elementary excitations are generated in metal films on dielectric substrates is important for the design and optimization of a number of different types of low-temperature detectors. We have measured the total energy loss in one relatively simple geometry that allows us to study these processes and compare measurements with calculation based upon a model for the various different processes. We have modeled the athermal phonon energy loss in this device by finding an evolving phonon distribution function that solves the system of kinetic equations for the interacting system of electrons and phonons. Using measurements of device parameters such as the Debye energy and the thermal diffusivity we have calculated the expected energy loss from this detector geometry, and also the position-dependent variation of this loss. We have also calculated the predicted impact on measured spectral lineshapes and have shown that they agree well with measurements. In addition, we have tested this model by using it to predict the performance of a number of other types of detector with different geometries, where good agreement is also found.

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Section: Methodsmentioning

confidence: 53%

“…For both of these experiments, the quasithermal signal is measured using a magnetic penetration thermometer (MPT). 11,14,15 This type of thermometer utilizes the temperature-dependent diamagnetic susceptibility of a superconducting film. A schematic diagram of the two experiments is depicted in Fig.…”

Section: Methodsmentioning

confidence: 99%

Athermal energy loss from x-rays deposited in thin superconducting films on solid substrates

et al. 2013

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“…Noise measurements [7] with ati b = 1.25 rnA and T = SO mK showed the presence of no significant excess noise, only SQUID and phonon noise. The phonon noise component extended up to 5 kHz, and was consistent with the expected electron-phonon and Kapitza thermal conductance between the bilayer and substrate.…”

Section: Ill Experimental Resultsmentioning

confidence: 86%

“…We have reported a solution to this long-standing challenge that gives a transition width suitable for producing a detector with usable dynamic range [7][8]. We use a MoAu bilayer, with a Tc of 140 mK, as our superconducting temperature sensor, just as is used in many transition-edge-sensor microcalorimeters.…”

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confidence: 99%

Superconducting Effects in Optimization of Magnetic Penetration Thermometers for X-Ray Microcalorimeters

Stevenson

Balvin

Bandler

et al. 2013

IEEE Trans. Appl. Supercond.

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Abstnlct-We have made higb.resolution x-ray microcalorimeters ulioK 5nperconducting MoAn bUayers Ind Nb meander coils. The temperature sensor is a. Magnetic Penetration Thermometer (MPT). Operation Is similar to metallic magnetic calorimeters, but instead of the magnetic susceptibility of a paramagnetic alloy, we use the diamagnetic response of the 8uperconducting MoA. to selln temperature changes In an x-ray absorber. Flux-temperature responsivtty can be large for small sensor heat capacity, with enough dynamic range for appUcations. We find models ·of observed flux-temperature curves require several effects to explain flux penetration or expulsion in the microscopic devices. The superconductor is non~ local, with large coherence length and weak pInning of OUI. At lowest temperatures, behavior i.J dominated by Kreening currents that vary as a result of the temperature dependence of the magnetic penetration depth, modified by the effe~t of tbe nonuniformiry oftbe applied field occurring on a scale comparable to the coherence length. In the temperature regime where responslvity is greatest, spadal variations in the order parameter become important: both local variations as flux enterslIeaves the film and an intermediate state is formed, and globally as changing stability of the electrical circuit creates a Meissner transition and flux is expelled/penetrates to minimize free energy.Index Tt'nu--About four key words or phrases in aJphabetical order, separated by commas.

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“…Figure 1(b) shows an example of the measured variation of flux coupling to a SQUID for an MPT as a function of temperature [2], and how this variation compares with a typical MMC. The figure shows data acquired for two different magnetic-field-producing currents for both an MMC and an MPT.…”

Section: Introductionmentioning

confidence: 99%

Magnetically Coupled Microcalorimeters

et al. 2012

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Magnetic calorimeters have been under development for over 20 years targeting a wide variety of different applications that require very high resolution spectroscopy. They have a number of properties that distinguish them from other low temperature detectors. In this paper we review these properties and emphasize the types of application to which they are most suited. We will describe what has been learned about the best materials, geometries, and read-out amplifiers and our understanding of the measured performance and theoretical limits. While most magnetic calorimeter research has concentrated on the use of paramagnets to provide the temperature sensitivity, recently magnetically coupled microcalorimeters have been in development that utilize the diamagnetic response of superconductors. We will contrast some of the properties of the two different magnetic sensor types. J Low Temp Phys (2012) 167:254-268 255 Fig. 1 (Color online) (a) Basic schematic for both types of magnetically coupled microcalorimeters.(b) Measured SQUID signal as a function of temperature for MMC and MPT microcalorimeters. The geometry of the pick-up loop and coupling to the SQUID is identical for these two measurements. Two different curves generated by two different magnetic field producing currents are shown for each sensor type

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Performance of Magnetic Penetration Thermometers for X-ray Astronomy

Cited by 9 publications

References 9 publications

Athermal energy loss from x-rays deposited in thin superconducting films on solid substrates

Athermal energy loss from x-rays deposited in thin superconducting films on solid substrates

Superconducting Effects in Optimization of Magnetic Penetration Thermometers for X-Ray Microcalorimeters

Magnetically Coupled Microcalorimeters

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