Microcalorimeter/EBIT measurements of X-ray spectra of highly charged ions

Spectra of highly charged Ar, Kr, Xe and Fe ions, produced in an Electron Beam Ion Trap (EBIT), have been recorded in a broad X-ray energy band (0.2 keV to 10 keV) with a microcalorimeter detector. The first analysis of the Kr spectra has been completed and most of the spectral lines have been identified as transitions of B- to Al-like Kr. Line intensity ratios of Fe XVII have been measured and compared with theoretical models.

Astrophysics and spectroscopy with microcalorimeters on an electron beam ion trap

The importance of the combination of electron beam ion trap (EBIT) spectroscopy with X-ray microcalorimeters in the field of astrophysics was discussed. X-ray astronomy involves heavily charged ion instruments , especially EBIT, to obtain improved quality atomic data. In this regard, the research program at the National Institute of Standards and Technology, which uses X-ray spectroscopic methods to study plasma and atomic physics, was also discussed.

Xrase: The X-Ray Spectroscopic Explorer

The X-Ray Spectroscopic Explorer (XRASE) has a unique combination of features that will make it possible to address many of NASA’s scientific goals. These include how galaxy clusters form, the physics and chemistry of the ISM, the heating of stellar coronae, the amount and content of intergalactic baryonic matter, the mass of black holes and the formation of disks and jets in AGN and galactic binaries. XRASE has a thin foil, multilayered telescope with a large collecting area up to 10 keV, especially in the Fe Kα region (1100 cm2). Its microcalorimeter array combines high energy resolution (7 eV at 6 keV) and efficiency with a field-of-view of 26 arcmin2. A deep orbit allows for long, conti…

X-ray and gamma-ray astronomy with NTD germanium-based microcalorimeters

We report on the performance of our NTD-Ge microcalorimeters. To date, the spectral resolution for x-ray and gamma-ray lines from radioactive sources and laboratory plasmas is 4.8 eV in the entire 1 - 6 keV band and 52 eV at 60 keV. Technical details responsible for this performance are presented as well as an innovative electro-thermal approach for enhancing count-rate capability.

Laboratory astrophysics survey of key x-ray diagnostic lines using a microcalorimeter on an electron beam ion trap

Cosmic plasma conditions created in an electron beam ion trap (EBIT) make it possible to simulate the dependencies of key diagnostic X-ray lines on density, temperature, and excitation conditions that exist in astrophysical sources. We used a microcalorimeter for such laboratory astrophysics studies because it has a resolving power ≈1000, quantum efficiency approaching 100%, and a bandwidth that spans the X-ray energies from 0.2 keV to 10 keV. Our microcalorimeter, coupled with an X-ray optic to increase the effective solid angle, provides a significant new capability for laboratory astrophysics measurements. Broadband spectra obtained from the National Institute of Standards and Technology…

A microcalorimeter spectrometer for the investigation of laboratory plasmas

We describe a cryostat and 2-stage ADR specifically designed for making measurements at the NIST EBIT (Electron Beam Ion Trap) facility. The design is compact and consists of a single helium bath with two vapor-cooled shields. The 2-stage ADR has two separate magnets and two heat switches. The interface between the EBIT and microcalorimeter array will also be described.

Analysis of broadband x-ray spectra of highly charged krypton from a microcalorimeter detector of an electron-beam ion trap

Spectra of highly charged Kr ions, produced in an electron-beam ion trap (EBIT), have been recorded in a broad x-ray energy band (0.3 keV to 4 keV) with a microcalorimeter detector. Most of the spectral lines have been identified as transitions of B- to Al-like Kr. The transition energies have been determined with 0.2% uncertainty. A semi-empirical EBIT plasma model has been created to calculate a synthetic spectrum of highly charged Kr and to determine a charge state distribution of Kr ions inside the EBIT.

EBIT diagnostics using X-ray spectra of highly ionized Ne

We have carried out a detailed analysis of highly ionized neon spectra collected at the NIST EBIT using an NTD germanium X-ray microcalorimeter developed at the Harvard-Smithsonian Center for Astrophysics [Nucl. Instr. and Meth. A 444 (2000) 156]. Our attention was focused especially on the Ne IX He-like triplet to check electron density diagnostics through the intercombination/forbidden line ratio. We have investigated possible effects of the ion dynamics on the plasma emission line intensities, looking at the dependence of the count-rate and the charge state distribution on the electron beam energy and current. The temperature and spatial distribution of the neon ions, and hence the overl…

Current status and future plans for the general antiparticle spectrometer (GAPS)

著者人数: 13名

Erratum: Search for Light Dark Matter in XENON10 Data [Phys. Rev. Lett.107, 051301 (2011)]

High Energy, High Resolution X-Ray Spectroscopy: Microcalorimeters For Nuclear Line Astrophysics

We introduce focusing optics and microcalorimeter spectroscopy to nuclear line emission astrophysics with a balloon payload concept called, B‐MINE. It is designed to probe the deepest regions of a supernova explosion by detecting 44Ti emission at 68 keV with spatial and spectral resolutions that are sufficient to determine the velocity distribution of the 44Ti emitting region. B‐MINE has a thin plastic foil telescope multilayered to maximize the reflectivity in a 20 keV band centered at 68 keV and a microcalorimeter array optimized for the same energy band. This combination provides a reduced background, an energy resolution of 50 eV and a 3σ sensitivity in 106 s of 6 × 10−8 ph cm−2 s−1 at …

Emission-Line Intensity Ratios in F[CLC]e[/CLC] [CSC]xvii[/CSC] Observed with a Microcalorimeter on an Electron Beam Ion Trap

We report new observations of emission line intensity ratios of Fe XVII under controlled experimental conditions, using the National Institute of Standards and Technology electron beam ion trap (EBIT) with a microcalorimeter detector. We compare our observations with collisional-radiative models using atomic data computed in distorted wave and R-matrix approximations, which follow the transfer of the polarization of level populations through radiative cascades. Our results for the intensity ratio of the 2p6 1S0-2p53d 1P1 15.014 A line to the 2p6 1S0-2p53d 3D1 15.265 A line are 2.94 ± 0.18 and 2.50 ± 0.13 at beam energies of 900 and 1250 eV, respectively. These results are not consistent wit…

The General Antiparticle Spectrometer (GAPS) - Hunt for dark matter using low energy antideuterons

The GAPS experiment is foreseen to carry out a dark matter search using a novel detection approach to detect low-energy cosmic-ray antideuterons. The theoretically predicted antideuteron flux resulting from secondary interactions of primary cosmic rays with the interstellar medium is very low. So far not a single cosmic antideuteron has been detected by any experiment, but well-motivated theories beyond the standard model of particle physics, e.g., supersymmetry or universal extra dimensions, contain viable dark matter candidates, which could led to a significant enhancement of the antideuteron flux due to self-annihilation of the dark matter particles. This flux contribution is believed to…

Laboratory astrophysics and microanalysis with NTD-germanium-based X-ray microcalorimeters

With the ability to create cosmic plasma conditions in the laboratory it is possible to investigate the dependencies of key diagnostic X-ray lines on density, temperature, and excitation conditions that exist in astrophysical sources with X-ray optics and a high-resolution X-ray microcalorimeter. The same instrumentation can be coupled to scanning electron microscopes or X-ray fluorescence probes to analyze the elemental and chemical composition of electronic, biological, geological and particulate materials. We describe how our microcalorimeter and X-ray optics provide significantly improved capabilities for laboratory astrophysics and microanalysis.

Indirect Dark Matter Search with Antideuterons: Progress and Future Prospects for General Antiparticle Spectrometer (GAPS)

We report on recent accelerator testing of a prototype general antiparticle spectrometer (GAPS). GAPS is a novel approach for indirect dark matter searches that exploits the antideuterons produced in neutralino-neutralino annihilations. Many supersymmetry models, as well as other models based on extra dimensions, predict a primary antideuteron flux from dark matter annihilation that is much greater than the secondary and tertiary background sources at low energies. The GAPS method involves capturing antiparticles in a target material into excited energy states. The X-rays that are emitted as the antiparticle cascades to lower energy states before the exotic atom decays serve as a fingerprin…

Modeling the energy thermalization of X-ray photons in a microcalorimeter with superconducting absorber

We present a modeling of the response of a microcalorimeter to the absorption of X-ray photons, based on the main microscopical processes responsible for the energy thermalization. In particular, we have modeled a microcalorimeter with superconducting tin absorber (350 micron x 350 micron x 7 micron) and neutron transmutation doped (NTD) germanium thermistor (75 micron x 50 micron x 150 micron). Such a detector, operated at 60 mK, is expected to achieve a spectral resolution as good as 1 eV FWHM in the soft X-ray energy range, based on the known sources of thermal and electronic noise. Nevertheless, the best spectral resolution measured in laboratory experimental tests is of about 5 eV FWHM…

A search for light dark matter in XENON10 data

We report results of a search for light (3.5x10^{-42} cm^2, for a dark matter particle mass m_{\chi}=8 GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.