| 1. |
- Åkesson, Torsten, et al.
(författare)
-
Implementation of the DTMROC-S ASIC for the ATLAS TRT Detector in a 0.25μm CMOS technology
- 2003
-
Ingår i: IEEE Nuclear Science Symposium and Medical Imaging Conference. - 1082-3654. - 0780376366 ; 1, s. 549-553
-
Konferensbidrag (refereegranskat)abstract
- The DTMROC-S is a 16-channeI front-end chip developed for the signal processing of the ATLAS straw tube detector, TRT. Due to a highly radioactive environment, the chip is fabricated in a commercial 0.25μm CMOS technology hardened by layout techniques and, in addition, a special methodology was used to improve the circuit's robustness against Single Events Effects (SEE) caused by ionizing particles. Exhaustive internal test features were foreseen to simplify and ensure comprehensive design verification, high fault coverage and throughput. Compared to the previous version of the chip done in a 0.8μm radiation-hard CMOS and despite of all supplementary features, the Deep-Sub-Micron (DSM) technology results in a much smaller chip size that increases the production yield and lowers the power consumption.
|
|
| 2. |
- Clément, Christophe, et al.
(författare)
-
Identification of Pile-up Using the Quality Factor of Pulse Shapes in the ATLAS Tile Calorimeter
- 2011
-
Ingår i: IEEE Nuclear Science Symposium Conference Record. - 1082-3654. ; , s. 1188-1193
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS experiment records data from the proton-proton collisions produced by the Large Hadron Col lider (LHC). The Tile Calorimeter is the hadronic sampling calorimeter of ATLAS in the region |η|<1.7. It uses iron absorbers and scintillators as active material. The LHC will provide collisions every 25 ns, putting very strong requirements on the energy measurement in presence of energy deposits from different collisions in the same read out window and physical calorimeter channel (pile-up). In 2011 the LHC is running with filled bunches at 50 ns spacing and at intensities which yield up to about 8 proton-proton collisions per bunch crossing. We present a quality factor that can be computed online for each collision and for each calorimeter channel within the 10 μs latency of the ATLAS first level trigger (L1 trigger), and could allow to identify calorimeter channels presenting pile-up. In presence of a poor quality factor the data from the corresponding channel is read out with additional information to allow for an offline dedicated treatment of the signals to account for pile-up.
|
|
| 3. |
- Hall-Wilton, Richard, et al.
(författare)
-
Detectors for the European Spallation Source
- 2012
-
Ingår i: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC). - 1082-3654. ; , s. 4283-4289
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) in Lund, Sweden will become the world's leading neutron source for the study of materials by 2025. First neutrons will be produced in 2019. It will be a long pulse source, with an average beam power of 5 MW delivered to the target station. The pulse length will be 2.86 ms and the repetition rate 14 Hz. The ESS is presently in a design update phase, which ends in February 2013 with a Technical Design Report (TDR). Construction will subsequently start with the goal of bringing the first seven instruments into operation in 2019 at the same time as the source. The full baseline suite of 22 instruments will be brought online by 2025. These instruments present numerous challenges for detector technology in the absence of the availability of Helium-3, which is the default choice for detectors for instruments built until today. Additionally a new generation of source requires a new generation of detector technologies to fully exploit the opportunities that this source provides. This contribution presents briefly the current status of the ESS, and outlines the timeline to completion. The number of instruments and the framework for the decisions on which instruments should be built are shown. For a conjectured full instrument suite, which has been chosen for demonstration purposes for the TDR, a snapshot of the current expected detector requirements is presented. An outline as to how some of these requirements might be tackled is shown. Given that the delivery of the ESS TDR is only a few months away, this contribution reflects strongly the content of the TDR.
|
|
| 4. |
- Kanaki, Kalliopi, et al.
(författare)
-
Statistical Energy Determination in Neutron Detector Systems for Neutron Scattering Science
- 2012
-
Ingår i: 2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC). - 1082-3654. ; , s. 162-166
-
Konferensbidrag (refereegranskat)abstract
- This contribution evaluates the feasibility and potential of a statistical determination of the neutron energy for thermal and cold neutrons in the new generation of neutron detectors. For the European Spallation Source (ESS), sited in Lund, Sweden, which is planned to be operational in 2019, and the world's leading source for the study of materials with neutrons by 2025, novel neutron detectors represent a critical technology that needs to be developed. The discussion here is based upon B-10 based thin-film detectors for neutron scattering science; however such a development is generalisable to other converter materials and potentially relevant to applications outside of neutron scattering science.
|
|
| 5. |
- Peterson, Mikael, et al.
(författare)
-
Construction of a Pre-Clinical High Resolution Tomographic Scintillation Camera System
- 2009
-
Ingår i: 2009 IEEE Nuclear Science Symposium Conference Record, Vols 1-5. - 1082-3654. ; , s. 3670-3671
-
Konferensbidrag (refereegranskat)abstract
- We are constructing a High Resolution Tomographic Scintillation Camera System for small animal imaging. The system consists of a CsI(Tl) scintillator coupled to a military surplus image intensifier with a CCD camera focused on the output window. The system operates in photons counting mode and the spatial resolution is improved by centroid calculations for every photon interaction. The system can be mounted on an optical rail together with a pinhole collimator and a rotating table. A hot rod phantom was filled with Tl-201 or Tc-99m solute and imaged. The phantom rod diameters range from 1.1 to 1.6 mm. 64 projections were acquired (300 s/projection) with 1 mm pinhole insert. Data was reconstructed using an OSEM algorithm. Image data was corrected for decay, position non-linearities in image intensifier and the angular dependence of the pinhole. The reconstructed resolution is 13 mm (by visual inspection) for both Tc-99m and Tl-201. Higher spatial resolution is achievable with smaller pinhole diameters. Future work includes optimizing spatial resolution and sensitivity of a single system using analytical calculations, experiments and simulations. With the conclusions drawn from those calculations we plan to construct a multi-camera system.
|
|
| 6. |
- Sundin, Kurt, et al.
(författare)
-
SIMIND based pinhole imaging: Development and validation
- 2007
-
Ingår i: 2007 IEEE Nuclear Science Symposium Conference Record, vols 1-11. - 1082-3654. - 9781424409228 ; , s. 3998-4005
-
Konferensbidrag (refereegranskat)abstract
- Monte Carlo programs, like the SIMIND program, have become increasingly used to simulate imaging systems like the scintillation camera and SPECT systems. Up to now, it has not been able to simulate a pinhole-imaging device with SIMIND. The aim of this work was to develop a routine for pinhole-imaging consisting of a knife-edge collimator and a conical shielding. The routine tracks the path of each photon through the pinhole-collimator and scores if photons either i) pass geometrically through the pinhole ii) penetrate through the edges of the pinhole or iii) being scattered in the collimator. This allows for calculation of fractions of geometrical, penetrating and scattered photons that contribute to an image. Variance reduction is implementing by forcing the photon, emitted from the last interaction point (or from the initial decay location), into a direction towards the center of the pinhole. Characteristic x-ray emissions from photon interactions are included. Results from simulations were compared to results from experimental studies using a SPECT system with a physical pinhole-collimator. The parameters compared were here the sensitivity (cps/MBq) and the shape of line-spread functions as function of distance. Comparisons were also made with results from previously published Monte Carlo simulations of pinhole collimators for different radionuclides. Results from our simulations mostly showed a good agreement but for some cases we found differences especially in the values of the fraction of geometrical, penetrating and scattered photons when comparing to previously reported results. Our conclusion is, however, that the routine provides accurate pinhole collimator simulations.
|
|
| 7. |
- Örbom, Anders, et al.
(författare)
-
Serial digital autoradiography with a silicon strip detector as a high resolution imaging modality for TRT Dosimetry
- 2007
-
Ingår i: 2007 IEEE Nuclear Science Symposium Conference Record, vols 1-11. - 1082-3654. - 9781424409228 ; , s. 4054-4056
-
Konferensbidrag (refereegranskat)abstract
- This study aims to investigate the possibility of implementing serial autoradiography using a silicon strip detector as an imaging modality in pre-clinical radionuclide therapy research, in order to study the effect of non-uniform uptake on absorbed dose distribution and biological response. Tumor tissues expressing CD20 (B-cell lymphoma) or carcinoembryonic antigen (CEA; colorectal cancer) were excised from animals injected with I-131-labelled anti-CD20 or anti-CEA antibodies and antibody fragments. The tumors were cryosectioned at 100 mu m and imaged using a real-time silicon- strip imager with a pixel-size of 50 mu m. Software was developed to correct for image artifacts and to realign the image sections into a volume by a two-step process with least square error and mutual information registration measures. The realigned volumes were convolved with beta dose point kernels to provide the dose rate distribution for I-131 and Y-90 at the time of sacrifice. Using these volumes, comparisons can be made between uptake and penetration of different antibodies and the dose rate uniformity of different radionuclides. Simulations performed using measured I-131 and I-125 energy spectra showed that energy separation with less than 5% error could be performed with 100 counts per pixel. Imaging and subsequent separation of a sample containing both I-131 and I-125 proved the possibility of simultaneous imaging of two targeting agents in the same tissue. Thinner tissue sections were also set aside and successfully used for H&E staining and immunohistochemistry to enable future comparison of uptake and dose rate in different cell-type populations in the tissue. This method successfully provides high-resolution activity and dose rate volumes and has potential for multi-labeling imaging and co-registration with histology. As a complimentary imaging modality it can aid in investigating the effect of non-uniform uptake. Optimization is still needed in both the sectioning protocol and realignment software.
|
|
