The XRS microcalorimeter spectrometer at the Livermore electron beam ion trap

Abstract

NASA's X-ray spectrometer (XRS) microcalorimeter instrument has been operating at the electron beam ion trap (EBIT) facility at Lawrence Livermore National Laboratory since July of 2000. The spectrometer is currently undergoing its third major upgrade to become an easy to use and extremely high-performance instrument for a broad range of EBIT experiments. The spectrometer itself is broadband, capable of simultaneously operating from 0.1 to 12 keV and has been operated at up to 100 keV by manipulating its operating conditions. The spectral resolution closely follows the spaceflight version of the XRS, beginning at 10 eV FWHM at 6 keV in 2000, upgraded to 5.5 eV in 2003, and will hopefully be ∼3.8 eV in the fall of 2007. Here we review the operating principles of this unique instrument, the extraordinary science that has been performed at EBIT over the last six years, and prospects for future upgrades. Specifically, we discuss upgrades to cover the high-energy band (to at least 100 keV) with a high quantum efficiency detector and prospects for using a new superconducting detector to reach 0.8 eV resolution at 1 keV and 2 eV at 6 keV with high counting rates. PACS Nos.: 52.25.Os, 52.70.La, 95.85.Nv, 32.30.Rj, 07.85.Fv, 78.70.En Résumé : Le spectromètre-X à microcalorimètre (XRS) de la NASA est en opération au piège ionique à faisceau d'électrons de Livermore (EBIT) depuis juillet 2000. Le spectromètre subit actuellement sa troisième mise à jour pour devenir un instrument facile à utiliser et extrêmement performant dans un large domaine des mesures possibles à EBIT. Le spectromètre lui-même est à large bande, capable de fonctionner simultanément entre 0.1 et 12 keV et a opéré jusqu'à 100 keV en ajustant ses paramètres d'opération. La résolution spectrale suit de près la version en orbite du XRS, débutant à 10 eV FWHM à 6 keV en 2000, améliorée à 5.5 eV en 2003 et nous espérons atteindre ∼3.8 eV à l'automne 2007. Nous passons ici en revue les principes d'opération de cet instrument unique, l'extraordinaire science faite à EBIT ces 6 dernières années et les promesses d'avenir. Plus spécifiquement, nous visons des améliorations pour couvrir le domaine de haute énergie (au moins jusqu'à 100 keV) avec une haute efficacité quantique et la perspective d'introduire un détecteur supraconducteur pour atteindre une résolution de 0.8 eV à 1 keV et 2 eV à 6 keV, avec de hauts taux de comptage. [Traduit par la Rédaction]

Laboratory measurements of the dielectronic recombination satellite transitions of He-like Fe XXV and H-like Fe XXVI

“…Microcalorimeters determine the photon energy by measuring the temperature rise of the photon-absorbing materials. The state-of-the-art instruments reach energy resolutions of 4 e V at 6 ke V with further improvements possible [16,17]. The flight engineering model of the X-ray spectrometer XRS, as the Suzaku microcalorimeter was furmally known, was installed at the EBIT-I electron beam ion trap of the Lawrence Livermore National Laboratory [P, 18], and has made important contributions to the laboratcry astrophysics measurements carried out with this device.…”

Guest Editor’s Notes on the “Atoms” Special Issue on “Perspectives of Atomic Physics with Trapped Highly Charged Ions”

“…Microcalorimeters, in contrast, offer coverage of a wide part of the X-ray range combined with a line width of only a few eV. There are various pathways to this goal; one practically proven design has been developed at NASA Goddard and used in its various incarnations at the Livermore EBIT laboratory [68][69][70]. In the latest of these instruments, the EBIT Calorimeter Spectrometer (ECS) [71], 36 individual detector pixels are mounted in an array.…”

Calibration of a high resolution grating soft x-ray spectrometer

“…12 The present ECS consists of a 6 × 6 array of HgTe pixels cryogenically-cooled to 50 mK using an adiabatic de-magnetization refrigerator in a liquid 3 He/ 4 He bath. The array consists of 624 × 624 µm 2 × 8 µm thick pixels for mid-energy 0.1 -10 keV photons interspersed with 624 × 500 µm 2 × 100 µm thick pixels for improved high energy 0.5 -100 keV photon detection.…”

“…7 We report the calibration of a High-Resolution variablespaced Grating, flat-field Spectrometer (HRGS) 8,9 with a backthinned CCD detector for the wavelength range of 10 -50 Å on the electron beam ion trap (EBIT) x-ray source at the Fusion and Astrophysics (FAST) data and instrument calibration facility at the Lawrence Livermore National Laboratory (LLNL). 10,11 The EBIT calorimeter spectrometer (ECS) 12 was used to crosscalibrate the grating instrument on EBIT-I by recording the soft x-ray emission simultaneously. We show an example of the recorded spectra from both instruments.…”