Back side puls

Analogue signal from common electrode of pixelated detector for triggering and spectroscopy.

Takové hrátky s analogovým signálem ... spektroskopií ... galvanickými odělovači ... optikou ... Americiem ... Plutoniem ...
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Prezentace

IWORID 2011 - 13th International Workshop on Radiation Imaging Detectors, Zurich
3. 7. 2011 - 7. 7. 2011
Analog signal from common electrode of pixelated detector for triggering and spectroscopy
Poster

Publikace

Analogue signal from common electrode of pixelated detector for triggering and spectroscopy
M. Platkevič, J. Jakůbek, Z. Vykydal, C. Granja
Journal of Instrumentation 6 C11023 doi:10.1088/1748-0221/6/11/C11023 (2011)

Hardware

Optical galvanic separator
Galvanic separation module between Timepix detector and USB interface for suppression of the electromagnetic noise - based on optical fibers.

Galvanic separator
Galvanic separation module between Timepix detector and USB interface for suppression of the electromagnetic noise - based on ADuM1400 digital isolators.

Granty

Pokročilé techniky detekce ionizujícího záření
- TA01010164, Program na podporu aplikovaného výzkumu a experimentálního vývoje ALFA. TA0 - Technologická agentura České republiky (TA ČR) , 2011 - 2014

Využití radionuklidů a ionizujícího záření
- MSM6840770040, Ministerstvo školství, mládeže a tělovýchovy (MŠMT) , 2007 - 2012

Příprava, modifikace a charakterizace materiálů energetickým zářením
- LC06041, Centra základního výzkumu, Ministerstvo školství, mládeže a tělovýchovy (MŠMT) , 2006 - 2011

ABSTRACT: A significant advantage of high granularity and highly sensitive semiconductor pixel detectors is the possibility to directly observe single tracks of charged particles. In many cases, however, these particles are accompanied with unwanted background radiation overlapping traces of interest. The detection selectivity can be increased using a triggering approach usually provided by an external trigger from other detecting devices such as ionization chambers, scintillating or semiconductor detectors. A self-trigger from the same sensor would be highly desirable. Unfortunately, the Medipix/Timepix devices are not equipped with such self-trigger feature. A solution which is presented in this contribution makes use of the analog signal taken from the common electrode of the pixelated sensor. This signal, called back-side-pulse, is amplified by a custom made charge sensitive preamplifier which, after shaping, can be used as fast trigger and as independent spectroscopic signal. The stability and energy resolution of this analog signal is, however, strongly affected by electromagnetic noise interference from the digital read-out chip and its interface. In this article we present the solution based on the construction of a hardware galvanic shielded extender which isolates and effectively suppresses such noise interference. The result enables selective self-triggering according to the deposited energy of the detected particle. The technique and operation of the prototype are demonstrated on measurements with heavy charged particles from radioactive α-sources 241Am and 239Pu.

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Illustration of testing setup for detection of alpha particles with Timepix.
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Experimental setup with digital isolators.
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Experimental setup with optical fibers.
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Back-side pulse spectra of a combined 241Am (5.486 MeV) and 239Pu (5.156 MeV) alpha source in the three investigated setup architectures: a) Timepix directly connected to the USB interface, b) Timepix chip not powered and not connected to the USB interface, and c) Timepix connected to the USB interface via optical fibres.