Investigation of lag and ghosting in amorphous selenium flat-panel x-ray detectors

Author(s):  
Wei Zhao ◽  
Giovanni DeCrescenzo ◽  
John A. Rowlands
Keyword(s):  
2012 ◽  
Vol 210 (3) ◽  
pp. 580-584 ◽  
Author(s):  
Zexiang Chen ◽  
Miao Dong ◽  
Chun Li ◽  
Shengzi Shao ◽  
Tianyong Hu ◽  
...  

2003 ◽  
Vol 764 ◽  
Author(s):  
Jang-Yong Choi ◽  
Ji-Koon Park ◽  
Dong-Gil Lee ◽  
Sang-Sik Kang ◽  
Sang-Hee Nam

AbstractNowadays, large area, flat panel solid state detectors are being investigated for digital radiography. In this paper, development and evaluation of a selenium-based flat-panel digital xray detector are described. The prototype detector has a pixel pitch of 139μm and a total active imaging area of 7″×8.5″, giving a total of 1.9 million pixel. This detector include a x-ray imaging layer of amorphous selenium as a photoconductor which is evaporated in vacuum state on a TFT flat panel, to make signals in proportion to incident x-ray. The film thickness was about 500μm. To evaluate the imaging performance of the digital radiography (DR) system developed in our group, sensitivity, linearity of the response of exposure, the modulation transfer function(MTF) and detective quantum efficiency(DQE) of detector was measured. The measured sensitivity was 4.16×106 ehp/pixel mR at the bias field of 10 V/μm: The beam condition was 41.9 KeV. Measured MTF at 2.5 lp/mm was 52%, and the DQE at 1.5 lp/mm was 75%.


2020 ◽  
Vol 35 (S1) ◽  
pp. S38-S42
Author(s):  
Soraia Rodrigues de Azeredo ◽  
Roberto Cesareo ◽  
Angel Guillermo Bustamante Dominguez ◽  
Ricardo Tadeu Lopes

Precious ornaments from the Museum Royal Tombs of Sipán were analyzed by X-ray computed microtomography (microCT). The ornaments analyzed were golden earrings produced by the Moche culture that flourished along the north coast of present-day Peru between approximately 100 and 600 AD. Sipán, also known as Huava Rajada, is a mochica archaeological complex in the north of Peru. In particular, the spectacular jewelry, mainly composed of gold, silver, and copper alloys, gilded copper, and tumbaga, from the Museum “Royal Tombs of Sipán,” in Lambayeque, north of Peru, are some of the most sophisticated metalworking ever produced of pre-Columbian America. A portable microCT system consisting of a high-resolution flat panel detector and a mini X-ray tube were used for the structural analysis of these ornaments. The microCT images show parts of the internal structure, highlighting the manufacturing technique and gold sheets joining techniques of the Moche artisans. Furthermore, the advantage of using the portable microCT system for nondestructive testing is clear when the sample cannot be taken to the laboratory.


2008 ◽  
Vol 1066 ◽  
Author(s):  
Kyung-Wook Shin ◽  
Mohammad R. Esmaeili-Rad ◽  
Andrei Sazonov ◽  
Arokia Nathan

ABSTRACTHydrogenated nanocrystalline silicon (nc-Si:H) has strong potential to replace the hydrogenated amorphous silicon (a-Si:H) in thin film transistors (TFTs) due to its compatibility with the current industrial a-Si:H processes, and its better threshold voltage stability [1]. In this paper, we present an experimental TFT array backplane for direct conversion X-ray detector, using inverted staggered bottom gate nc-Si:H TFT as switching element. The TFTs employed a nc-Si:H/a-Si:H bilayer as the channel layer and hydrogenated amorphous silicon nitride (a-SiNx) as the gate dielectric; both layers deposited by plasma enhanced chemical vapor deposition (PECVD) at 280°C. Each pixel consists of a switching TFT, a charge storage capacitor (Cpx), and a mushroom electrode which serves as the bottom contact for X-ray detector such as amorphous selenium photoconductor. The chemical composition of the a-SiNx was studied by Fourier transform infrared spectroscopy. Current-voltage measurements of the a-SiNx film demonstrate that a breakdown field of 4.3 MV/cm.. TFTs in the array exhibits a field effect mobility (μEF) of 0.15 cm2/V·s, a threshold voltage (VTh) of 5.71 V, and a subthreshold leakage current (Isub) of 10−10 A. The fabrication sequence and TFT characteristics will be discussed in details.


2003 ◽  
Author(s):  
Douglas Albagli ◽  
Heather Hudspeth ◽  
George E. Possin ◽  
Ji Ung Lee ◽  
Paul R. Granfors ◽  
...  
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