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@PHDTHESIS{Schwemmbauer:639249,
      author       = {Schwemmbauer, Christina},
      othercontributors = {Lindner, Axel and Januschek, Friederike and Garutti, Erika},
      title        = {{E}xploring {P}otential: {ALPS} {II}’s {TES} {D}etection
                      {S}ystem for {D}irect {D}ark {M}atter {S}earches},
      school       = {Universität Hamburg},
      type         = {Dissertation},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron DESY},
      reportid     = {PUBDB-2025-04369, DESY-THESIS-2025-019},
      series       = {DESY-THESIS},
      pages        = {156},
      year         = {2025},
      note         = {Dissertation, Universität Hamburg, 2025},
      abstract     = {AbstractThis thesis both proposes and experimentally
                      explores the opportunity to operate TransitionEdge Sensors
                      (TES) as detectors for Dark Matter (DM)-scattering by
                      simultaneouslyemploying them as target and sensor. By
                      exploiting their microcalorimetric capabilitiesand
                      sensitivity to low energy depositions, competitive limits
                      can be set on low mass DMinteractions based on electron
                      scattering. Further limits on absorption and
                      DM-nucleonscattering can be determined as well.With a
                      sensitive area of 25 μm × 25 μm, 20 nm thickness, and a
                      mass of just 0.2 ng, theTES sensors are not comparable to
                      large scale experiments searching for ∼GeV-scaleWeakly
                      Interacting Massive Particles (WIMPs). However, the
                      sensors’ sensitivity to energydepositions as low as ∼
                      0.3 eV enables sensitivity to much lower sub-MeV DM masses.
                      TESare operated on the transition curve between the normal
                      and superconducting state, wherethe sensor is sensitive to
                      the smallest energy depositions, yielding detectable pulses.
                      Basedon the detector’s sensitivity, especially to single
                      near-infrared photons, it should also besensitive to sub-MeV
                      to high MeV DM particles scattering in its electron or
                      nucleon systems.By exploiting the similarity of these
                      processes and using the ALPS II experiment’s TESdetection
                      system, dedicated DM searches were performed with two
                      distinct TES detectionmodules.In dedicated experimental
                      setups, the well-known ALPS II-optimized analysis scheme
                      wasemployed to determine ideal detector configurations for
                      DM searches in need of a sufficientlylarge energy bandwidth.
                      In a next step, the detector’s energy response was
                      investigatedby analyzing the pulse shapes of photons from
                      different lasers with photon energies from0.76 eV to 1.41
                      eV. During these tests, a linear proportionality between the
                      pulse’s integralwith the energy was found, while at the
                      same time, the rise and decay time of the pulsesstayed
                      predominantly constant over these energies. This performance
                      along with subsequentsimulations of signal pulses over a
                      larger energy range can be used for a dedicated
                      eventselection to isolate photon-like pulses from the
                      various backgrounds present in the system.Therefore, these
                      background sources, including fast (baseline) noise spikes,
                      are mitigatedby dedicated analysis and straightforward
                      cutting schemes.Dedicated DM search measurements are
                      performed using two different detector modules.The
                      measurement and analysis pipeline was optimized for module
                      TES D. A secondmodule TES F with a setup adjusted for DM
                      search measurements is presented in apreliminary analysis,
                      as well. DM search measurements of 489 h and 400 h have
                      beenperformed, respectively. By applying dedicated event
                      selections to each, limits on differentDM parameter spaces
                      have been set for both, considering expected DM interaction
                      rates invthe explored DM mass range. The resulting limits
                      are compared to results originating fromsimilar experimental
                      efforts, especially one employing Superconducting Nanowire
                      SinglePhoton Detectors (SNSPDs) as both target and sensor,
                      as well. The TES modules are ableto surpass limits set by
                      the first generation of these SNSPDs for lower masses in the
                      lightmediator limit. However, limits set by a dedicated
                      optimized second generation SNSPDexperiment exceed both.
                      Nevertheless, this enhancement from a first to a second
                      upgradedgeneration already exemplifies the strength of such
                      an approach, as similar improvementscan be explored for TES
                      detectors as well. Therefore, projections for possible
                      futuredetection scenarios are explored, presenting the
                      strength of possible second generation TESdetection systems.
                      Hence, it was shown for the first time, that TES detectors
                      can be used asa simultaneous sensor and target in direct DM
                      experiments with a plethora of possibilitiesfor further
                      upgrades and optimization.},
      cin          = {ALPS},
      cid          = {I:(DE-H253)ALPS-20130318},
      pnm          = {611 - Fundamental Particles and Forces (POF4-611)},
      pid          = {G:(DE-HGF)POF4-611},
      experiment   = {EXP:(DE-H253)ALPS-20150101},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      doi          = {10.3204/PUBDB-2025-04369},
      url          = {https://bib-pubdb1.desy.de/record/639249},
}