Development of the TIGRE Compton telescope for intermediate-energy gamma-ray astronomy

O'Neill, T. J.; Bhattacharya, D.; Polsen, M.; Zych, A. D.; Samimi, J.; Akyüz, A.

doi:10.1109/tns.2003.809700

Cited by 35 publications

(19 citation statements)

References 9 publications

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“…Employing semiconductor imaging spectrometers, with their good resolutions, is hence a promising approach to realize high sensitivity Compton telescopes. From this point of view, Compton telescopes based on Si, Ge ,CZT and CdTe are proposed and development is on-going by many groups [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Recent results from a Si/CdTe semiconductor Compton telescope

Tanaka

Watanabe

Takeda

et al. 2006

Nuclear Instruments and Methods in Physics Research Section A:

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We are developing a Compton telescope based on high resolution Si and CdTe detectors for astrophysical observations in sub-MeV/MeV gamma-ray region. Recently, we constructed a prototype Compton telescope which consists of six layers of double-sided Si strip detectors and CdTe pixel detectors to demonstrate the basic performance of this new technology. By irradiating the detector with gamma-rays from radio isotope sources, we have succeeded in Compton reconstruction of images and spectra. The obtained angular resolution is 3.9 • (FWHM) at 511 keV, and the energy resolution is 14 keV (FWHM) at the same energy. In addition to the conventional Compton reconstruction, i.e., drawing cones in the sky, we also demonstrated a full reconstruction by tracking Compton recoil electrons using the signals detected in successive Si layers. By irradiating 137 Cs source, we successfully obtained an image and a spectrum of 662 keV line emission with this method. As a next step, development of larger double-sided Si strip detectors with a size of 4 cm × 4 cm is underway to improve the effective area of the Compton telescope. We are also developing a new low-noise analog ASIC to handle the increasing number of channels. Initial results from these two new technologies are presented in this paper as well.

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Section: Introductionmentioning

confidence: 99%

Recent results from a Si/CdTe semiconductor Compton telescope

Tanaka

Watanabe

Takeda

et al. 2006

Nuclear Instruments and Methods in Physics Research Section A:

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“…In addition the track information for the electrons can also be used to improve the reconstruction process since only a segment of the backprojected cone-corresponding to the achievable electron direction measurement-is considered [2], [8]. This would greatly improve the signal-to-noise ratio after reconstruction.…”

Section: Compton Camera For Small Animal Imaging With Nuclear Tramentioning

confidence: 99%

“…This would greatly improve the signal-to-noise ratio after reconstruction. It also plays a role for the determination of the polarization [8].…”

Section: Compton Camera For Small Animal Imaging With Nuclear Tramentioning

confidence: 99%

Vertex detection in a stack of Si-drift detectors for high resolution gamma-ray imaging

Walenta

Brill²,

Castoldi³

et al. 2005

IEEE Trans. Nucl. Sci.

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Usually the position resolution in imaging applications with gamma rays is limited due to the range of secondary reaction products to a few mm. Here a new approach will be presented using the vertex of the gamma interaction as the quantity for position measurement. Because the dominant interaction is the Compton effect the vertex detection method as used in particle physics needs a number of essential modifications. Therefore a detector system is investigated consisting of a stack of Si-drift detectors for the vertex detection of the first Compton interaction and a secondary absorption detector where the position of the scattered photon is detected. A number of effects and possible solutions will be discussed including depth of interaction measurement and track reconstruction of the Compton electron which yields useful information. Another very promising approach of measuring the track projection as in a TPC (Time Projection Chamber) will be presented including first successful measurements in a gas detector. Because the expected rate in the first and second detector is of the order of 1 MHz and 10 MHz respectively the concept of read out electronics and data processing based on VLSI custom chips for signal shaping and first buffering and digital pipe-line processors based on FPGAs is presented. Finally a full system for small animal imaging based on the principle of a Compton Camera will be discussed in terms of achievable resolution and sensitivity.Index Terms-Compton camera, gamma camera, Si-drift detector, vertex detection. F OR imaging applications with gamma rays a position resolution at the order of will be highly desirable for applications in safety inspection, material science, portal imaging, astrophysics and -of course -nuclear tracer methods in bio-medicine and nuclear medicine. The latter has received recently a large attention for small animal imaging.Because of the inherent range of the secondary reaction products from absorbed gamma rays in the order of a few mm this Manuscript Fig. 1. Limits of position resolution for gamma rays. The range of secondary radiation is indicated. The smaller could be due to the range of photo-or Compton-electrons, the larger due to fluorescence or scattered radiation. Fig. 2. Absorption length of primary and scattered radiation in detector material.represents the physical limit for position resolution in the actual imaging devices.In Fig. 1 the principle is visualized where it is assumed for simplicity that the emission of the secondary radiation is isotropic. A sphere for the range of the ejected electrons and a mostly larger sphere for the emitted photons are indicated. In Fig. 2 the range (absorption length) for the scattered radiation is compared to the absorption length of the primary radiation. For higher energies (about 1 MeV) the detector-even for heavy scintillators as LSO-has to be fairly thick ( 20 mm) and the range of the scattered radiation is not much smaller (about 10 mm) limiting the intrinsic resolution correspondingly.In the proposed work a new appr...

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“…The basic TIGRE instrument [1,2] is shown in Figure 1. The telescope consists of two major components.…”

Section: The Tigre Telescopementioning

confidence: 99%

“…The Maximum Likelihood method estimates parameters which maximize the probability of observing the data given a specific model for the data. The data model included a Crab-like source and a realistic balloon environment background; the source PSF is constructed from the summation of individual arcs representing the scatter angle, scatter photon direction and the electron track information, and can be expressed as a parametric fit given by Equation (2). The total model prediction for pixel (i,j) is given by…”

Section: Likelihood Analysismentioning

confidence: 99%