34 research outputs found
A CLINICAL CASE OF WEBER-CHRISTIAN DISEASE
A clinical case of elderly female patient diagnosed with Weber-Christian disease developed on the background of long standing chronic autoimmune thyroiditis with impaired function of the thyroid gland (hypothyroidism) and unstable hormonal status, after surgery (hysterectomy, oophorectomy)
Canonical formulation of self-gravitating spinning-object systems
Based on the Arnowitt-Deser-Misner (ADM) canonical formulation of general
relativity, a canonical formulation of gravitationally interacting classical
spinning-object systems is given to linear order in spin. The constructed
position, linear momentum and spin variables fulfill standard Poisson bracket
relations. A spatially symmetric time gauge for the tetrad field is introduced.
The achieved formulation is of fully reduced form without unresolved
constraints, supplementary, gauge, or coordinate conditions. The canonical
field momentum is not related to the extrinsic curvature of spacelike
hypersurfaces in standard ADM form. A new reduction of the tetrad degrees of
freedom to the Einstein form of the metric field is suggested.Comment: 6 pages. v2: extended version; identical to the published one. v3:
corrected misprints in (24) and (39); improved notation; added note regarding
a further reference
Phase Measurement for Driven Spin Oscillations in a Storage Ring
This paper reports the first simultaneous measurement of the horizontal and
vertical components of the polarization vector in a storage ring under the
influence of a radio frequency (rf) solenoid. The experiments were performed at
the Cooler Synchrotron COSY in J\"ulich using a vector polarized, bunched
deuteron beam. Using the new spin feedback system, we
set the initial phase difference between the solenoid field and the precession
of the polarization vector to a predefined value. The feedback system was then
switched off, allowing the phase difference to change over time, and the
solenoid was switched on to rotate the polarization vector. We observed an
oscillation of the vertical polarization component and the phase difference.
The oscillations can be described using an analytical model. The results of
this experiment also apply to other rf devices with horizontal magnetic fields,
such as Wien filters. The precise manipulation of particle spins in storage
rings is a prerequisite for measuring the electric dipole moment (EDM) of
charged particles
Spin tune mapping as a novel tool to probe the spin dynamics in storage rings
Precision experiments, such as the search for electric dipole moments of
charged particles using storage rings, demand for an understanding of the spin
dynamics with unprecedented accuracy. The ultimate aim is to measure the
electric dipole moments with a sensitivity up to 15 orders in magnitude better
than the magnetic dipole moment of the stored particles. This formidable task
requires an understanding of the background to the signal of the electric
dipole from rotations of the spins in the spurious magnetic fields of a storage
ring. One of the observables, especially sensitive to the imperfection magnetic
fields in the ring is the angular orientation of stable spin axis. Up to now,
the stable spin axis has never been determined experimentally, and in addition,
the JEDI collaboration for the first time succeeded to quantify the background
signals that stem from false rotations of the magnetic dipole moments in the
horizontal and longitudinal imperfection magnetic fields of the storage ring.
To this end, we developed a new method based on the spin tune response of a
machine to artificially applied longitudinal magnetic fields. This novel
technique, called \textit{spin tune mapping}, emerges as a very powerful tool
to probe the spin dynamics in storage rings. The technique was experimentally
tested in 2014 at the cooler synchrotron COSY, and for the first time, the
angular orientation of the stable spin axis at two different locations in the
ring has been determined to an unprecedented accuracy of better than
rad.Comment: 32 pages, 15 figures, 7 table
Phase locking the spin precession in a storage ring
This letter reports the successful use of feedback from a spin polarization
measurement to the revolution frequency of a 0.97 GeV/ bunched and polarized
deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control
both the precession rate ( kHz) and the phase of the horizontal
polarization component. Real time synchronization with a radio frequency (rf)
solenoid made possible the rotation of the polarization out of the horizontal
plane, yielding a demonstration of the feedback method to manipulate the
polarization. In particular, the rotation rate shows a sinusoidal function of
the horizontal polarization phase (relative to the rf solenoid), which was
controlled to within a one standard deviation range of rad. The
minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753
kHz, which changes the precession rate by 26 mrad/s. Such a capability meets a
requirement for the use of storage rings to look for an intrinsic electric
dipole moment of charged particles
Measurement of deuteron carbon vector analyzing powers in the kinetic energy range 170-380 MeV
A measurement of vector analyzing powers in elastic deuteron-carbon
scattering has been performed at the Cooler Synchrotron COSY of
Forschungszentrum J\"ulich, Germany. Seven kinetic beam energies between 170
and 380 MeV have been used. A vector-polarized beam from a polarized deuteron
source was injected, accelerated to the final desired energy and stored in
COSY. A thin needle-shaped diamond strip was used as a carbon target, onto
which the beam was slowly steered. Elastically scattered deuterons were
identified in the forward direction using various layers of scintillators and
straw tubes. Where data exist in the literature (at 200 and 270 MeV), excellent
agreement of the angular shape was found. The beam polarization of the
presented data was deduced by fitting the absolute scale of the analyzing power
to these references. Our results extend the world data set and are necessary
for polarimetry of future electric dipole moment searches at storage rings.
They will as well serve as an input for theoretical description of polarized
hadron-hadron scattering
Spin decoherence and off-resonance behavior of radiofrequency-driven spin rotations in storage rings
Radiofrequency-driven resonant spin rotators are routinely used as standard
instruments in polarization experiments in particle and nuclear physics.
Maintaining the continuous exact parametric spin-resonance condition of the
equality of the spin rotator and the spin precession frequency during operation
constitutes one of the challenges. We present a detailed analytic description
of the impact of detuning the exact spin resonance on the vertical and the
in-plane precessing components of the polarization. An important part of the
formalism presented here is the consideration of experimentally relevant
spin-decoherence effects. We discuss applications of the developed formalism to
the interpretation of the experimental data on the novel pilot bunch approach
to control the spin-resonance condition during the operation of the
radiofrequency-driven Wien filter that is used as a spin rotator in the first
direct deuteron electric dipole moment measurement at COSY. We emphasize the
potential importance of the hitherto unexplored phase of the envelope of the
horizontal polarization as an indicator of the stability of the
radiofrequency-driven spin rotations in storage rings. The work presented here
serves as a satellite publication to the work published concurrently on the
proof of principle experiment about the so-called pilot bunch approach that was
developed to provide co-magnetometry for the deuteron electric dipole moment
experiment at COSY.Comment: 31 pages, 10 figures, 5 table
Pilot bunch and co-magnetometry of polarized particles stored in a ring
In polarization experiments at storage rings, one of the challenges is to
maintain the spin-resonance condition of a radio-frequency spin rotator with
the spin-precessions of the orbiting particles. Time-dependent variations of
the magnetic fields of ring elements lead to unwanted variations of the spin
precession frequency. We report here on a solution to this problem by shielding
(or masking) one of the bunches stored in the ring from the high-frequency
fields of the spin rotator, so that the masked pilot bunch acts as a
co-magnetometer for the other signal bunch, tracking fluctuations in the ring
on a time scale of about one second. While the new method was developed
primarily for searches of electric dipole moments of charged particles, it may
have far-reaching implications for future spin physics facilities, such as the
EIC and NICA.Comment: 5 pages, 3 figures + references + supplemental material (6 pages, 2
figures, 6 tables + references