46 research outputs found
A compact and robust diode laser system for atom interferometry on a sounding rocket
We present a diode laser system optimized for laser cooling and atom
interferometry with ultra-cold rubidium atoms aboard sounding rockets as an
important milestone towards space-borne quantum sensors. Design, assembly and
qualification of the system, combing micro-integrated distributed feedback
(DFB) diode laser modules and free space optical bench technology is presented
in the context of the MAIUS (Matter-wave Interferometry in Microgravity)
mission.
This laser system, with a volume of 21 liters and total mass of 27 kg, passed
all qualification tests for operation on sounding rockets and is currently used
in the integrated MAIUS flight system producing Bose-Einstein condensates and
performing atom interferometry based on Bragg diffraction. The MAIUS payload is
being prepared for launch in fall 2016.
We further report on a reference laser system, comprising a rubidium
stabilized DFB laser, which was operated successfully on the TEXUS 51 mission
in April 2015. The system demonstrated a high level of technological maturity
by remaining frequency stabilized throughout the mission including the rocket's
boost phase
First 10 kg of Naked Germanium Detectors in Liquid Nitrogen installed in the GENIUS-Test-Facility
The first four naked high purity Germanium detectors were installed
successfully in liquid nitrogen in the GENIUS-Test-Facility (GENIUS-TF) in the
GRAN SASSO Underground Laboratory on May 5, 2003. This is the first time ever
that this novel technique aiming at extreme background reduction in search for
rare decays is going to be tested underground. First operational parameters are
presented.Comment: 10 pages, latex2e, 8 figures, Was presented (first presentation) at
4th International Conference on Particle Physics Beyond the Standard Model
BEYOND'2003, Castle Ringberg, Germany, 9-14 June, 2003, Springer, Heidelberg,
Germany, 2003, edited by H.V. Klapdor-Kleingrothau
Interferometry with Bose-Einstein Condensates in Microgravity
Atom interferometers covering macroscopic domains of space-time are a
spectacular manifestation of the wave nature of matter. Due to their unique
coherence properties, Bose-Einstein condensates are ideal sources for an atom
interferometer in extended free fall. In this paper we report on the
realization of an asymmetric Mach-Zehnder interferometer operated with a
Bose-Einstein condensate in microgravity. The resulting interference pattern is
similar to the one in the far-field of a double-slit and shows a linear scaling
with the time the wave packets expand. We employ delta-kick cooling in order to
enhance the signal and extend our atom interferometer. Our experiments
demonstrate the high potential of interferometers operated with quantum gases
for probing the fundamental concepts of quantum mechanics and general
relativity.Comment: 8 pages, 3 figures; 8 pages of supporting materia
New limits on dark--matter WIMPs from the Heidelberg--Moscow experiment
New results after 0.69 kg yr of measurement with an enriched 76Ge detector of
the Heidelberg--Moscow experiment with an active mass of 2.758 kg are
presented. An energy threshold of 9 keV and a background level of 0.042
counts/(kg d keV) in the energy region between 15 keV and 40 keV was
reached.The derived limits on the WIMP--nucleon cross section are the most
stringent limits on spin--independent interactions obtained to date by using
essentially raw data without background subtraction.Comment: 8 pages (latex) including 5 postscript figures and 2 tables. To
appear in Phys. Rev. D, 15. December 199
Investigation of β + β + and β + /EC decay of 106 Cd
A low background scintillation detector with a CdWO4 crystal of 1.046 kg was used to search for β+β+ and β+/EC processes in 106Cd. For the neutrinoless mode the limits T1/2(0νβ+β+) ≥ 2.2 · 1019 y and T1/2(0νβ+/EC) ≥ 5.5 · 1019 y were obtained with 90% C.L. For the possible two neutrino decay limits of T1/2(2νβ+β+) ≥ 9.2 · 1017 y and 1/2(2νβ+/EC) ≥ 2.6 · 1017 y have been determined with 99% C.L
Latest Results from the Heidelberg-Moscow Double Beta Decay Experiment
New results for the double beta decay of 76Ge are presented. They are
extracted from Data obtained with the HEIDELBERG-MOSCOW, which operates five
enriched 76Ge detectors in an extreme low-level environment in the GRAN SASSO.
The two neutrino accompanied double beta decay is evaluated for the first time
for all five detectors with a statistical significance of 47.7 kg y resulting
in a half life of (T_(1/2))^(2nu) = [1.55 +- 0.01 (stat) (+0.19) (-0.15)
(syst)] x 10^(21) years. The lower limit on the half-life of the 0nu beta-beta
decay obtained with pulse shape analysis is (T_(1/2))^(0_nu) > 1.9 x 10^(25)
[3.1 x 10^(25)] years with 90% C.L. (68% C.L.) (with 35.5 kg y). This results
in an upper limit of the effective Majorana neutrino mass of 0.35 eV (0.27 eV).
No evidence for a Majoron emitting decay mode or for the neutrinoless mode is
observed.Comment: 14 pages, revtex, 6 figures, Talk was presented at third
International Conference ' Dark Matter in Astro and Particle Physics' -
DARK2000, to be publ. in Proc. of DARK2000, Springer (2000). Please look into
our HEIDELBERG Non-Accelerator Particle Physics group home page:
http://www.mpi-hd.mpg.de/non_acc
Neutrino mass spectrum and neutrinoless double beta decay
The relations between the effective Majorana mass of the electron neutrino,
, responsible for neutrinoless double beta decay, and the neutrino
oscillation parameters are considered. We show that for any specific
oscillation pattern can take any value (from zero to the existing
upper bound) for normal mass hierarchy and it can have a minimum for inverse
hierarchy. This means that oscillation experiments cannot fix in general
. Mass ranges for can be predicted in terms of oscillation
parameters with additional assumptions about the level of degeneracy and the
type of hierarchy of the neutrino mass spectrum. These predictions for
are systematically studied in the specific schemes of neutrino mass and flavor
which explain the solar and atmospheric neutrino data. The contributions from
individual mass eigenstates in terms of oscillation parameters have been
quantified. We study the dependence of on the non-oscillation
parameters: the overall scale of the neutrino mass and the relative mass
phases. We analyze how forthcoming oscillation experiments will improve the
predictions for . On the basis of these studies we evaluate the
discovery potential of future \znbb decay searches. The role \znbb decay
searches will play in the reconstruction of the neutrino mass spectrum is
clarified. The key scales of , which will lead to the discrimination
among various schemes are: eV and eV.Comment: 47 pages, 35 figure
Neutrino oscillation constraints on neutrinoless double beta decay
We have studied the constraints imposed by the results of neutrino
oscillation experiments on the effective Majorana mass || that characterizes
the contribution of Majorana neutrino masses to the matrix element of
neutrinoless double-beta decay. We have shown that in a general scheme with
three Majorana neutrinos and a hierarchy of neutrino masses (which can be
explained by the see-saw mechanism), the results of neutrino oscillation
experiments imply rather strong constraints on the parameter ||. From the
results of the first reactor long-baseline experiment CHOOZ and the Bugey
experiment it follows that || < 3x10^{-2} eV if the largest mass-squared
difference is smaller than 2 eV^2. Hence, we conclude that the observation of
neutrinoless double-beta decay with a probability that corresponds to || >
10^{-1} eV would be a signal for a non-hierarchical neutrino mass spectrum
and/or non-standard mechanisms of lepton number violation.Comment: 20 pages, including 4 figure
New Results from the Cryogenic Dark Matter Search Experiment
Using improved Ge and Si detectors, better neutron shielding, and increased
counting time, the Cryogenic Dark Matter Search (CDMS) experiment has obtained
stricter limits on the cross section of weakly interacting massive particles
(WIMPs) elastically scattering from nuclei. Increased discrimination against
electromagnetic backgrounds and reduction of neutron flux confirm
WIMP-candidate events previously detected by CDMS were consistent with neutrons
and give limits on spin-independent WIMP interactions which are >2X lower than
previous CDMS results for high WIMP mass, and which exclude new parameter space
for WIMPs with mass between 8-20 GeV/c^2.Comment: 4 pages, 4 figure
Exclusion limits on the WIMP-nucleon cross-section from the Cryogenic Dark Matter Search
The Cryogenic Dark Matter Search (CDMS) employs low-temperature Ge and Si
detectors to search for Weakly Interacting Massive Particles (WIMPs) via their
elastic-scattering interactions with nuclei while discriminating against
interactions of background particles. For recoil energies above 10 keV, events
due to background photons are rejected with >99.9% efficiency, and surface
events are rejected with >95% efficiency. The estimate of the background due to
neutrons is based primarily on the observation of multiple-scatter events that
should all be neutrons. Data selection is determined primarily by examining
calibration data and vetoed events. Resulting efficiencies should be accurate
to about 10%. Results of CDMS data from 1998 and 1999 with a relaxed
fiducial-volume cut (resulting in 15.8 kg-days exposure on Ge) are consistent
with an earlier analysis with a more restrictive fiducial-volume cut.
Twenty-three WIMP candidate events are observed, but these events are
consistent with a background from neutrons in all ways tested. Resulting limits
on the spin-independent WIMP-nucleon elastic-scattering cross-section exclude
unexplored parameter space for WIMPs with masses between 10-70 GeV c^{-2}.
These limits border, but do not exclude, parameter space allowed by
supersymmetry models and accelerator constraints. Results are compatible with
some regions reported as allowed at 3-sigma by the annual-modulation
measurement of the DAMA collaboration. However, under the assumptions of
standard WIMP interactions and a standard halo, the results are incompatible
with the DAMA most likely value at >99.9% CL, and are incompatible with the
model-independent annual-modulation signal of DAMA at 99.99% CL in the
asymptotic limit.Comment: 40 pages, 49 figures (4 in color), submitted to Phys. Rev. D;
v.2:clarified conclusions, added content and references based on referee's
and readers' comments; v.3: clarified introductory sections, added figure
based on referee's comment