Publications (30)
A SQUID-based microwave cavity search for dark-matter axions
The ADMX Collaboration, S. J. Asztalos, G. Carosi +12
Axions in the micro eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a stati…
Fission Fragment Angular Anisotropy in Neutron-Induced Fission of U Measured with a Time Projection Chamber
V. Geppert-Kleinrath, F. Tovesson, J. S. Barrett +33
Fission fragment angular distributions can provide an important constraint on fission theory, improving predictive fission codes, and are a prerequisite for a precise ratio cross s…
Axion Radiation from Strings
C. Hagmann, S. Chang, P. Sikivie
This paper revisits the problem of the string decay contribution to the axion cosmological energy density. We show that this contribution is proportional to the average relative in…
Experimental Results from an Antineutrino Detector for Cooperative Monitoring of Nuclear Reactors
N. S. Bowden, A. Bernstein, M. Allen +9
Our collaboration has designed, installed, and operated a compact antineutrino detector at a nuclear power station, for the purpose of monitoring the power and plutonium content of…
Axions from wall decay
S. Chang, C. Hagmann, P. Sikivie
We discuss the decay of axion walls bounded by strings and present numerical simulations of the decay process. In these simulations, the decay happens immediately, in a time scale…
A High Resolution Search for Dark-Matter Axions
L. D. Duffy, P. Sikivie, D. B. Tanner +7
We have performed a high resolution search for galactic halo axions in cold flows using a microwave cavity detector. The analysis procedure and other details of this search are des…
1H(n,el) as a Cross Section Reference in a White Source Neutron Beam With the fissionTPC
N. I. Walsh, J. T. Barker, N. S. Bowden +33
We provide a quantitative description of a method to measure neutron-induced fission cross sections in ratio to elastic hydrogen scattering in a white-source neutron beam with the…
Measurement of the normalized U(n,f)/U(n,f) cross section ratio from threshold to 30 MeV with the fission Time Projection Chamber
R. J. Casperson, D. M. Asner, J. Baker +61
The normalized U(n,f)/U(n,f) cross section ratio has been measured using the NIFFTE fission Time Projection Chamber from the reaction threshold to ~MeV. The fis…
Cosmic neutrinos and their detection
C. Hagmann
The standard Big-Bang theory predicts a cosmic neutrino background with an average number density of per flavor. The most promising way of its detection is measurin…
Neutron Induced Fission Fragment Angular Distributions, Anisotropy, and Linear Momentum Transfer Measured with the NIFFTE Fission Time Projection Chamber
D. Hensle, J. T. Barker, J. S. Barrett +46
The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) collaboration has performed measurements with a fission time projection chamber (fissionTPC) to study the fission…
Results from a High-Sensitivity Search for Cosmic Axions
C. Hagmann, D. Kinion, W. Stoeffl +13
We report the first results of a high-sensitivity (10^{-23} Watt) search for light halo axions through their conversion to microwave photons. At 90 percent confidence we exclude a…
A Relic Neutrino Detector
C. Hagmann
Probably the most promising way of detecting cosmic neutrinos is measuring the mechanical force exerted by elastic scattering of cosmic neutrinos from macroscopic targets. The expe…
Measurement of material isotopics and atom number ratio with alpha-particle spectroscopy for the NIFFTE fission Time Projection Chamber actinide target
M. Monterial, K. T. Schmitt, C. Prokop +37
We present the results of a measurement of isotopic concentrations and atomic number ratio of a double-sided actinide target with alpha-spectroscopy and mass spectrometry. The doub…
Results of a Search for Cold Flows of Dark Matter Axions
L. Duffy, P. Sikivie, D. B. Tanner +7
Theoretical arguments predict that the distribution of cold dark matter in spiral galaxies has peaks in velocity space associated with non-thermalized flows of dark matter particle…
The XENON Dark Matter Search Experiment
E. Aprile, K. L. Giboni, P. Majewski +14
The XENON experiment aims at the direct detection of dark matter in the form of WIMPs (Weakly Interacting Massive Particles) via their elastic scattering off Xe nuclei. A fiducial…
A 2nd generation cosmic axion experiment
C. Hagmann, W. Stoeffl, K. van Bibber +11
An experiment is described to detect dark matter axions trapped in the halo of our galaxy. Galactic axions are converted into microwave photons via the Primakoff effect in a static…
Measurement of the Pu(n,f)/U(n,f) Cross-Section Ratio with the NIFFTE fission Time Projection Chamber
L. Snyder, M. Anastasiou, N. S. Bowden +37
The Pu(n,f)/U(n,f) cross-section ratio has been measured with the fission Time Projection Chamber (fissionTPC) from 100 keV to 100 MeV. The fissionTPC provides thre…
A search for non-virialized axionic dark matter
J. Hoskins, J. Hwang, C. Martin +14
Cold dark matter in the Milky Way halo may have structure defined by flows with low velocity dispersion. The Axion Dark Matter eXperiment high resolution channel is especially sens…
A Search for Scalar Chameleons with ADMX
G. Rybka, M. Hotz, L. J Rosenberg +11
Scalar fields with a "chameleon" property, in which the effective particle mass is a function of its local environment, are common to many theories beyond the standard model and co…
First results from a second generation galactic axion experiment
C. Hagmann, D. Kinion, W. Stoeffl +15
We report first results from a large scale search for dark matter axions. The experiment probes axion masses of 1.3-13 micro-eV at a sensitivity which is about 50 times higher than…
A Search for Hidden Sector Photons with ADMX
A. Wagner, G. Rybka, M. Hotz +12
Hidden U(1) gauge symmetries are common to many extensions of the Standard Model proposed to explain dark matter. The hidden gauge vector bosons of such extensions may mix kinetica…
Axions from string decay
C. Hagmann, S. Chang, P. Sikivie
We have studied numerically the evolution and decay of axion strings. These global defects decay mainly by axion emission and thus contribute to the cosmological axion density. The…
Design and performance of the ADMX SQUID-based microwave receiver
S. J. Asztalos, G. Carosi, C. Hagmann +12
The Axion Dark Matter eXperiment (ADMX) was designed to detect ultra-weakly interacting relic axion particles by searching for their conversion to microwave photons in a resonant c…
First measurement of the ionization yield of nuclear recoils in liquid argon
T. H. Joshi, S. Sangiorgio, A. Bernstein +9
This Letter details a measurement of the ionization yield () of 6.7 keV atoms stopping in a liquid argon detector. The of 3.6-6.3 detected $e^{-}/\mbox{keV}$,…
Studies of the motion and decay of axion walls bounded by strings
S. Chang, C. Hagmann, P. Sikivie
We discuss the appearance at the QCD phase transition, and the subsequent decay, of axion walls bounded by strings in N=1 axion models. We argue on intuitive grounds that the main…
Move of a large but delicate apparatus on a trailer with air-ride suspension
B. Thomas, D. Will, J. Heilman +17
When valuable delicate goods are shipped by truck, attention must be paid to vibrations that may cause damage. We present a case study of moving an extremely delicate 6230-kg super…
First demonstration of a sub-keV electron recoil energy threshold in a liquid argon ionization chamber
S. Sangiorgio, T. H. Joshi, A. Bernstein +9
We describe the first demonstration of a sub-keV electron recoil energy threshold in a dual-phase liquid argon time projection chamber. This is an important step in an effort to de…
An Improved RF Cavity Search for Halo Axions
S. J. Asztalos, R. F. Bradley, L. Duffy +10
The axion is a hypothetical elementary particle and cold dark matter candidate. In this RF cavity experiment, halo axions entering a resonant cavity immersed in a static magnetic f…
The cold axion populations
S. Chang, C. Hagmann, P. Sikivie
We give a systematic discussion of the contributions to the cosmological energy density in axions from vacuum realignment, string decay and wall decay. We call these the cold axion…
Experimental Constraints on the Axion Dark Matter Halo Density
Stephen J. Asztalos, E. Daw, H. Peng +12
Most of the mass of the Milky Way galaxy is contributed by its halo, presumably in the form of non-interacting cold dark matter. The axion is a compelling cold dark matter candidat…