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@PHDTHESIS{DreylingEschweiler:171082,
      author       = {Dreyling-Eschweiler, Jan},
      title        = {{A} superconducting microcalorimeter for low-flux detection
                      of near-infrared single photons},
      school       = {University of Hamburg},
      type         = {Dissertation},
      address      = {Hamburg},
      publisher    = {DESY, Verlag},
      reportid     = {DESY-2014-03157, DESY-THESIS-2014-016},
      pages        = {221},
      year         = {2014},
      note         = {Dissertation, University of Hamburg, 2014},
      abstract     = {This thesis covers the development and the characterization
                      of a single photon detector based on a superconducting
                      microcalorimeter. The detector development is motivated by
                      the Any Light Particle Search II (ALPS II) experiment at
                      DESY in Hamburg, which searches for weakly interacting
                      sub-eV particles (WISPs). Therefore, a detection of
                      low-fluxes of 1064 nm light is required. The work is divided
                      in three analyses: the characterization of a milli-kelvin
                      (mK) cryostat, the characterization of superconducting
                      sensors for single photon detection, and the determination
                      of dark count rates concerning 1064 nm signals.Firstly, an
                      adiabatic demagnetization refrigerator (ADR) is
                      characterized, which allows to reach mK-temperatures. During
                      commissioning, the ADR cryostat is optimized and prepared to
                      stably cool superconducting sensors at 80 mK ± 25 μK. It
                      is found that sensors can be continuously operated for ∼20
                      h before recharging the system in <2 h. Furthermore, the
                      adiabatic system reaches a chance of success of ∼80 $\%$
                      for a recharge without technical problems.Secondly,
                      superconducting sensors are analyzed. The focus is on
                      microcalorimetric transition-edge sensors (TESs) based on 20
                      nm Tungsten (W) films fabricated by the U.S. National
                      Institute of Standards and Technology (NIST). NIST TESs have
                      a near unity detection efficiency for 1064 nm light
                      (literature value). The energy resolution for 1064 nm
                      signals is measured to be <8 $\%.$ The exponential falling
                      time of a photon pulse is 1.5 μs. Furthermore, by
                      determining TES parameters, it is found that the linear TES
                      theory describes measured photon pulses well. The TES
                      response is read out by a superconducting quantum
                      interference device (SQUID) fabricated by
                      Physikalisch-Technische Bundesanstalt (PTB). The system
                      bandwidth is measured to be 0.9 MHz. Finally, the operation
                      in the ADR cryostat as well as the ALPS II laboratory is
                      optimized. This setup forms the ALPS TES detector.Thirdly,
                      the background is measured to obtain a dark count rate for
                      1064 nm signals. The ALPS TES detector is calibrated by a
                      1064 nm single photon source and methods are developed to
                      analyze signals. In long-term measurements, background
                      events are measured by using different optical setups. By
                      operating the TES without an optical link outside
                      mK-environment, intrinsic background components are observed
                      and classified. This results in an intrinsic dark count rate
                      for 1064 nm signals of 1.0 · $10^-4$ $s^-1$ . By operating
                      a fiber-coupled TES, it is found that the dark count rate
                      for 1064 nm signals is dominated by pile-up events of
                      near-infrared thermal photons coming through the fiber from
                      the warm environment. Considering a detection efficiency of
                      ∼18 $\%,$ a dark count rate of 8.6 · $10^-3$ $s^-1$ is
                      determined for 1064 nm ALPS photons.Concerning ALPS II, this
                      results in a sensitivity gain compared to the ALPS I
                      detector. Furthermore, this thesis is the starting point of
                      TES detector development in Hamburg, Germany.},
      keywords     = {Dissertation (GND)},
      cin          = {ALPS / UNI/EXP},
      cid          = {I:(DE-H253)ALPS-20130318 / $I:(DE-H253)UNI_EXP-20120731$},
      pnm          = {514 - Theoretical Particle Physics (POF2-514)},
      pid          = {G:(DE-HGF)POF2-514},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.3204/DESY-THESIS-2014-016},
      url          = {https://bib-pubdb1.desy.de/record/171082},
}