Mechanism of Photostimulated Luminescence Process in BaFBr:Eu²⁺Phosphors

Abstract

The Palomar Transient Factory (PTF) Orion project is one of the experiments within the broader PTF survey, a systematic automated exploration of the sky for optical transients. Taking advantage of the wide (3. • 5 × 2. • 3) field of view available using the PTF camera installed at the Palomar 48 inch telescope, 40 nights were dedicated in 2009 December to 2010 January to perform continuous high-cadence differential photometry on a single field containing the young (7-10 Myr) 25 Ori association. Little is known empirically about the formation of planets at these young ages, and the primary motivation for the project is to search for planets around young stars in this region. The unique data set also provides for much ancillary science. In this first paper, we describe the survey and the data reduction pipeline, and present some initial results from an inspection of the most clearly varying stars relating to two of the ancillary science objectives: detection of eclipsing binaries and young stellar objects. We find 82 new eclipsing binary systems, 9 of which are good candidate 25 Ori or Orion OB1a association members. Of these, two are potential young W UMa type systems. We report on the possible low-mass (M-dwarf primary) eclipsing systems in the sample, which include six of the candidate young systems. Forty-five of the binary systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa binaries, at 0.2156509 ± 0.0000071 days, with flat-bottomed primary eclipses, and a derived distance that appears consistent with membership in the general Orion association. One of the candidate young systems presents an unusual light curve, perhaps representing a semi-detached binary system with an inflated low-mass primary or a star with a warped disk, and may represent an additional young Orion member. Finally, we identify 14 probable new classical T-Tauri stars in our data, along with one previously known (CVSO 35) and one previously reported as a candidate weak-line T-Tauri star (SDSS J052700.12+010136.8).

THE SPECTRUM AND TERM ANALYSIS OF CO iii MEASURED USING FOURIER TRANSFORM AND GRATING SPECTROSCOPY

“…Three plates were used for each spectrum, producing a total wavelength coverage of about 600 Å. The image plates were read with a rotary drum scanner (PerkinElmer Cyclone Storage Phosphor Scanner B41200 (see footnote 4)), which illuminates the plate with red light from a laser, while a photomultiplier tube detects the blue light emitted through photostimulated luminescence (Katto et al 1993;Iwabuchi et al 1994). The grating slit width used, 52 μm, was selected due to the inherent resolution limitation imposed by the scanner (pixel size ∼42 μm).…”

Two-dimensional measurement of natural radioactivity of granitic rocks by photostimulated luminescence technique.

“…Photostimulated luminescence (PSL) is a kind of photoluminescence phenomenon that occurs due to the release of trapped charge carriers into a band, an electron into the conduction band, or Iwabuchi et al, 1994). holes into the valence band. The photostimuable phosphors are characterized as exhibiting the longwavelength luminescence, as compared with incident light after the photoionization excitation.…”

“…In particular, barium fluorobromide doped with Eu 2+ (BaFBr:Eu 2+ ) has been investigated extensively as a phosphor which is capable to store X-ray information (von Seggern et al, 1988;Koschnick et al, 1991;Thomas et al, 1991). Takahashi et al (1984) and Iwabuchi et al (1994) Kawano and Ueda, 1966). 4-9 granodiorite, Kurihashi granodiorites, Kamaishi Mine (110-120 Ma, Kawano and Ueda, 1965a).…”

External Electromagnetic Field Induced Electronic Structures and Novel Optical Functions of Rare-Earth-Ion-Doped Glasses.

“…X-ray induced photostimulated luminescence in rare-earth-doped glasses Photostimulated luminescence, a phenomenon due to the photostimulated recombination of holes and electrons at traps which leave electrons in a long-lived excited state, has attracted considerable attention in recent years.20), 21) In photostimulated luminescence, a material excited by a light 1 for example, after the irradiation by X-rays, emits a light 2 whose wavelength is usually shorter than that of excitation light 1, and the intensity of light 2 is proportional to the ir radiation quantity of the X-ray in a certain dynamic range. 20) Photostimulable phosphor, BaFX: Eu2+ (X=Br, I), is now widely used as a detector in X-ray radiography.20) An imaging plate made of BaFX: Eu2+ (X=Br, I) has excellent characteristics, such as a wide dynamic range extending over more than five orders of magnitude, and high sensitivi ty which is one hundred or one thousand times more sensi tive than silver chloride films which are still used as X-ray image receptors.…”

“…We have observed the photostimulat ed luminescence phenomenon in reduced rare-earth-iondoped glasses.8)-11) We assume mechanism for the pho tostimulated luminescence in the glass is similar to that of the well studied BaFBr: Eu2+ photostimulable phosphor. 21) Eu2+ -doped fluoroaluminate glass was fabricated in a reducing atmosphere. Figure 2 shows the decay curve of the photostimulated luminescence at 400nm of the X-ray ir radiated sample, when excited continuously by the He-Ne laser (633nm).…”