33 pages, 18 figuresThe Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5m x 2.5m x 3m disturbances of the magnetic field are attenuated by factors of 5 to 50 at a bandwidth from $10^{-3}$ Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the nEDM measurement. These shielding factors apply to random environmental noise from arbitrary sources. This is achieved via a proportional-integral feedback stabilization system that includes a regularized pseudoinverse matrix of proportionality factors which correlates magnetic field changes at all sensor positions to current changes in the SFC coils

The application of the muon-spin rotation/relaxation (µSR) technique for studying type-I superconductivity is discussed. In the intermediate state, i.e. when a type-I superconducting sample with non-zero demagnetization factor N is separated into normal state and Meissner state (superconducting) domains, the µSR technique allows to determine with very high precision the value of the thermodynamic critical field Bc, as well as the volume of the sample in the normal and the superconducting state. Due to the microscopic nature of µSR technique, the Bc values are determined directly via measurements of the internal field inside the normal state domains. No assumptions or introduction of any type of measurement criteria are needed.Experiments performed on a 'classical' type-I superconductor, a cylindrically shaped β−Sn sample, allowed to reconstruct the full B − T phase diagram. The zero-temperature value of the thermodynamic critical field Bc(0) = 30.578(6) mT and the transition temperature Tc = 3.717(3) K were determined and found to be in a good agreement with the literature data. An experimentally obtained demagnetization factor is in very good agreement with theoretical calculations of the demagnetization factor of a finite cylinder. The analysis of Bc(T ) dependence within the framework of the phenomenological α−model allow to obtain the value of the superconducting energy gap ∆ = 0.59(1) meV, of the electronic specific heat γe = 1.781(3) mJ/mol K 2 and of the jump in the heat capacity ∆C(Tc)/γTc = 1.55(2).

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We have developed a storage bottle for ultracold neutrons (UCN) in order to measure the UCN density at the beamports of the Paul Scherrer Institute's (PSI) UCN source. This paper describes the design, construction and commissioning of the robust and mobile storage bottle with a volume comparable to typical storage experiments (32 L) e.g. searching for an electric dipole moment of the neutron.

The HESS! SAS is a set of three Sun sensors, which shall provide high bandwidth ( 128 Hz) information on the solar pointing of the rotating spacecraft (15 rpm). The precision of 0.4 arcsec relative (on a 1 level) is necessary in order to obtain the HESSI imaging resolution of 2 arcsec; the absolute accuracy of 1 arcsec is required for comparison with other measurements. Each SAS is based on focussing the Sun through a narrow bandwidth filter (670 nm) onto a 2048-element x (13i)2 linear CCD. A digital threshold algorithm is used to select N pixels that span each solar limb for inclusion in the telemetry. Determination of the 6 limb crossing locations provided by the 3 subsystems (over-) defines the position offset of the Sun in the rotating frame. In this paper we describe the mechanical and electronic configuration of the SAS FM and the results of the first test measurements. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/25/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx