Specific Heat of Holmium in Gold and Silver at Low Temperatures

Herbst, Matthew; Reifenberger, Andreas; Velte, C.; Dorrer, Holger; Düllmann, Ch. E.; Enss, C.; Fleischmann, Andreas; Gastaldo, L.; Kempf, Sebastian; Kieck, T.; Köster, U.; Mantegazzini, F.; Wendt, Κ.

doi:10.1007/s10909-020-02531-1

Cited by 3 publications

(3 citation statements)

References 38 publications

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“…After the implantation process, a second host material layer with similar thickness is deposited before structuring the second absorber layer on top, which fully encloses the 163 Ho source. The host material of choice is silver, in order to lower the heat capacity contribution from the 163 Ho ions with respect to gold in the temperature range around 20 mK [14].…”

Section: Designmentioning

confidence: 99%

Development and characterisation of high-resolution microcalorimeter detectors for the ECHo-100k experiment

Mantegazzini¹,

Kovac²,

Enss³

et al. 2023

Preprint

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The goal of the ECHo experiment is a direct determination of the absolute scale of the neutrino mass by the analysis of the end-point region of the 163 Ho electron capture (EC) spectrum. The results of the first phase of the experiment, ECHo-1k, have paved the way for the current phase, ECHo-100k, which aims at a sensitivity below 2 eV on the effective electron neutrino mass. In order to reach this goal, a new generation of high-resolution magnetic microcalorimeters with embedded 163 Ho have been developed and characterised. The design has been optimised to meet all the challenging requirements of the ECHo-100k experimental phase, such as excellent energy resolution, wafer scale implantation and multi-chip operation with multiplexing read-out. We present the optimisation studies, the final design of the detector array and the first characterisation studies. The results demonstrate that the detectors fully match and even surpass the requirements for the current experimental phase, ECHo-100k.

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Section: Designmentioning

confidence: 99%

Development and characterisation of high-resolution microcalorimeter detectors for the ECHo-100k experiment

Mantegazzini¹,

Kovac²,

Enss³

et al. 2023

Preprint

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“…For the ECHo experiment the optimal activity has been determined to be 10 Bq per pixel which, combined with a time resolution of MMC well-below 1 µs would lead to an unresolved pile-up fraction well-below 10 −5 and, at the same time lead to an additional heat capacity of less than 50% of the one of gold absorber and Ag:Er sensor when the detectors are operated at a temperature of 20 mK. In [33] the specific heat per Ho atom in gold and silver has been measured as a function of Ho concentration and it was shown that for temperature above 100 mK the temperature dependence of the Ho specific heat follows that one measured for pure Ho samples, showing a Schottky anomaly at about 250 mK. This fact might induce some issues for the optimization of TES-based detector for the HOLMES experiment for which an activity of 300 Bq per pixel and an operational temperature around 80 mK are presently considered.…”

Section: Re Based Experimentsmentioning

confidence: 99%

Neutrino mass measurements using cryogenic detectors

Gastaldo

2022

Preprint

Self Cite

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The determination of the absolute mass scale of neutrinos is one of the most important challenges in Particle Physics. The shape of the endpoint region of β -decay and electron capture (EC) spectra depends on the phase space factor, which, in turn, is function of the neutrino mass eigenstates. High energy resolution and high statistics measurements of β -and EC spectra are therefore considered a model-independent way for the determination of the neutrino mass scale. Since almost four decades, low temperature microcalorimeters are used for the measurement of low energy β -and EC spectra. The first efforts were focused on the development of large arrays for the measurement of the 187 Re β -spectrum. In the last ten years, the attention moved to EC of 163 Ho. This choice was mainly motivated by the very good performance which could be achieved with low temperature microcalorimeters enclosing 163 Ho with respect to microcalorimeters with absorber containing 187 Re. The development of low temperature microcalorimeters for the measurement of the finite neutrino mass is discussed and, in particular, the reasons for moving from 187 Re to 163 Ho. The possibility to reach sub-eV sensitivity on the effective electron neutrino mass with 163 Ho, thanks to the multiplexing of large microcalorimeter arrays is demonstrated. In conclusion, an overview on other nuclides which have been proposed as good candidates, motivated by the excellent performance of low temperature microcalorimeters is presented.

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“…For the ECHo experiment the optimal activity has been determined to be 10 Bq per pixel which, combined with a time resolution of MMCs well-below 1 s would lead to an unresolved pile-up fraction well-below 10 −5 . At the same time, such activity lead to an additional heat capacity of less than 50% of the one of the gold absorber and Ag:Er sensor, when the detectors are operated at a temperature of 20 mK [37].…”

Section: Ho Based Experimentsmentioning

confidence: 99%

Neutrino Mass Measurements Using Cryogenic Detectors

Gastaldo

2022

J Low Temp Phys

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The determination of the absolute mass scale of neutrinos is one of the most important challenges in Particle Physics. The shape of the endpoint region of $$\beta ^-$$ β - -decay and electron capture (EC) spectra depends on the phase space factor, which, in turn, is function of the masses of the neutrino mass eigenstates. High energy resolution and high statistics measurements of $$\beta ^-$$ β - and EC spectra are therefore considered a model-independent way for the determination of the neutrino mass scale. Since almost four decades, low temperature microcalorimeters are used for the measurement of low energy $$\beta ^-$$ β - and EC spectra. The first efforts were focused on the development of large arrays for the measurement of the $$^{187}$$ 187 Re $$\beta ^-$$ β - -spectrum. In the last ten years, the attention moved to EC of $$^{163}$$ 163 Ho. This choice was mainly motivated by the very good performance which could be achieved with low temperature microcalorimeters enclosing $$^{163}$$ 163 Ho with respect to microcalorimeters with absorber containing $$^{187}$$ 187 Re. The development of low temperature microcalorimeters for the measurement of the finite neutrino mass is discussed and, in particular, the reasons for moving from $$^{187}$$ 187 Re to $$^{163}$$ 163 Ho. The possibility to reach sub-eV sensitivity on the effective electron neutrino mass with $$^{163}$$ 163 Ho, thanks to the multiplexing of large microcalorimeter arrays is demonstrated. In conclusion, an overview on other nuclides which have been proposed as good candidates, motivated by the excellent performance of low temperature microcalorimeters is presented.

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Specific Heat of Holmium in Gold and Silver at Low Temperatures

Cited by 3 publications

References 38 publications

Development and characterisation of high-resolution microcalorimeter detectors for the ECHo-100k experiment

Development and characterisation of high-resolution microcalorimeter detectors for the ECHo-100k experiment

Neutrino mass measurements using cryogenic detectors

Neutrino Mass Measurements Using Cryogenic Detectors

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