Absolute efficiency of Gd<sub>2</sub>O<sub>2</sub>S:Tb screens under fluoroscopic conditions

Giakoumakis, G. E.; Nomicos, C. D.; Sandilos, P.

doi:10.1088/0031-9155/34/6/003

Cited by 25 publications

(20 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The phosphor is well-established in radiology: Gd 2 O 2 S:Tb. This phosphor is a good absorber of x-rays in the diagnostic energy region thanks to its K-edge at approximately 50 keV and emits light in the range of 382-622 nm, and a primary peak at 545 nm [20]. The peak wavelength matches the CCD sensitivity curve (see fig.…”

Section: The Devices -Their Function and Corresponding Optimization Smentioning

confidence: 62%

See 1 more Smart Citation

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

et al. 2014

View full text Add to dashboard Cite

The extrinsic (absolute) efficiency of a phosphor is expressed as the ratio of light energy emitted per unit area at the phosphor surface to incident x-ray energy fluence. A model described in earlier work has shown that by knowing the intrinsic efficiency, the particle size, the thickness and the light extinction factor ξ, it is possible to deduce the extrinsic efficiency for an extended range of particle sizes and layer thicknesses for a given design. The model has been tested on Gd 2 O 2 S:Tb and ZnS:Cu fluorescent layers utilized in two quality assurance devices, respectively, aimed for the assessment of light field and radiation field congruence in diagnostic radiology. The first unit is an established device based on both fluorescence and phosphorescence containing an x-ray sensitive phosphor (ZnS:Cu) screen comprising a long afterglow. Uncertainty in field edge position is estimated to 0.8 mm (k=2). The second unit is under development and based on a linear CCD sensor which is sensitized to x-rays by applying a Gd 2 O 2 S:Tb scintillator. The field profiles and the corresponding edge location are then obtained and compared. Uncertainty in field edge location is estimated to 0.1 mm (k=2).The properties of the radioluminescent layers are essential for the functionality of the devices and have been optimized utilizing the previously developed and verified model. A theoretical description of the maximization of phosphorescence is also briefly discussed as well as an interesting finding encountered during the development processes: focal spot wandering. The oversimplistic physical assumptions made in the radioluminescence model have not been found to lead the optimizing process astray. The obtained functionality is believed to be adequate within their respective limitations for both devices.

show abstract

Section: The Devices -Their Function and Corresponding Optimization Smentioning

confidence: 62%

“…The camera has its maximum response in the same region as the primary peak of the GOS. Images are adapted from [20] and the specifications sheet.…”

Section: Figurementioning

confidence: 99%

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Terbium-activated gadolinium oxysulfide phosphor (Gd 2 O 2 S:Tb) has been considered as one of the most efficient phosphors. It shows bright green luminescence and high efficiency under UV, cathode-ray and X-ray excitations [2]. It is known to be an efficient phosphor and has been put to practical use for cathodoluminescent and X-ray applications such as digital radiography, X-ray intensifying screens for medical diagnosis or cathode-ray screens for TV set for its high conversion efficiency (12-25%).…”

Section: Introductionsmentioning

confidence: 99%

Highly enhanced luminescence of Tb3+-activated gadolinium oxysulfide phosphor by doping with Zn2+ ions

Wang

Yang

Zhang

et al. 2010

Journal of Luminescence

View full text Add to dashboard Cite

“…While their properties were well studied for x-rays [172][173][174][175] because of the high demand from the medical field and their long history, to the author's knowledge, there was only one publication as of 2007 on the relativistic e-beam detection with such a scintillating screen [164].…”

Section: Introductionmentioning

confidence: 99%

Control of Laser Plasma Based Accelerators up to 1 GeV

Nakamura

2007

View full text Add to dashboard Cite

This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs.An ESM specialized for CDG-LWFAs with an unprecedentedly wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and output laser properties as well as a large angular acceptance (> ±10 mrad) were realized by employing a slitless scheme. A scintillating screen (LANEX Fast back ,LANEX-FB) -camera system allowed faster than 1 Hz operation and evaluation of the spatial properties of e-beams. The design provided sufficient resolution for the whole range of the ESM (below 5% for beams with 2 mrad divergence).The calibration between light yield from LANEX-FB and total charge, and a study on the electron energy dependence (0.071 to 1.23 GeV) of LANEX-FB were performed at the Advanced light source (ALS), Lawrence Berkeley National Laboratory (LBNL). Using this calibration data, the developed ESM provided a charge measurement as well.The production of high quality electron beams up to 1 GeV from a centimeter-scale ii accelerator was demonstrated. The experiment used a 310 µm diameter gas-filled capillary discharge waveguide that channeled relativistically-intense laser pulses (42 TW, A statistical analysis of the CDG-LWFAs' performance was carried out. By taking advantage of the high repetition rate experimental system, several thousands of shots were taken in a broad range of the laser and plasma parameters. An analysis program was developed to sort and select the data by specified parameters, and then to evaluate performance statistically.The analysis suggested that the generation of GeV-level beams comes from a highly unstable and regime. By having the plasma density slightly above the threshold density for self injection, 1) the longest dephasing length possible was provided, which led to the generation of high energy e-beams, and 2) the number of electrons injected into the wakefield was kept small, which led to the generation of high quality (low energy spread) e-beams by minimizing the beam loading effect on the wake. The analysis of the stable half-GeV beam regime showed the requirements for stable self injection and acceleration. A small change of discharge delay t dsc , and input energy E in , significantly affected performance.The statistical analysis provided information for future optimization, and suggested possible schemes for improvment of the stability and higher quality beam generation. A CDG-LWFA is envisioned as a construction block for the next generation accelerator, enabling significant cost and size reductions.

show abstract

Absolute efficiency of Gd₂O₂S:Tb screens under fluoroscopic conditions

Cited by 25 publications

References 14 publications

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

Highly enhanced luminescence of Tb3+-activated gadolinium oxysulfide phosphor by doping with Zn2+ ions

Control of Laser Plasma Based Accelerators up to 1 GeV

Contact Info

Product

Resources

About

Absolute efficiency of Gd2O2S:Tb screens under fluoroscopic conditions

Cited by 25 publications

References 14 publications

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

Optimizing two radioluminescence based quality assurance devices for diagnostic radiology utilizing a simple model

Highly enhanced luminescence of Tb3+-activated gadolinium oxysulfide phosphor by doping with Zn2+ ions

Control of Laser Plasma Based Accelerators up to 1 GeV

Contact Info

Product

Resources

About

Absolute efficiency of Gd₂O₂S:Tb screens under fluoroscopic conditions