X-ray Photon counting detectors are known as next generation x-ray detectors because they have advantages over general energy-integrating detectors. Since X-ray photons are counted, energy information can be obtained. In addition, because of the direct measurement without scintillation, the contrast-to-noise ratio is higher than the general charge integration detector. The photon counting...
Recently, many studies for development of the algorithm using image processing have been conducted to reduce the noise in medical image [1]. In this study, we proposed total variation (TV) noise reduction algorithm and confirmed application feasibility in the self-produced phantom by 3D printer. For that purpose, we designed the TV noise reduction algorithm using L1-norm gradient operator that...
Thanks to the dose characteristic so-called Bragg peak, proton therapy can deliver a very conformal dose to the target volume while minimizing the dose to adjacent normal tissues and critical organs. However, the proton dose distribution in the patient, especially the beam range might deviate from the planned one due to dose calculation errors, organ motions or patient setup errors. To...
Neutrino research is relatively new and still not well-known part of physics. Therefore, many neutrino detectors have been developed to investigate neutrino properties. This paper describes present status of highly-segmented scintillating detector S3, which was developed as a common effort of IEAP CTU in Prague and JINR, Dubna. Since detector material meets strict safety rules of nuclear power...
Semiโinsulating (SI) GaAs is one of the perspective candidates for fabrication of semiconductor Xโ and gammaโray detectors applicable in digital radiology instrumentations. Advantage of the bulk SI GaAs is the possibility of fabrication of a monolithic strip or matrix detectors in one substrate due to the creation of the space charge region under each blocking contact. We fabricated pixelated...
In recent years, digital indirect X-ray imaging sensors have been widely used in many dental imaging applications such as intraoral, panorama and dental CT. These digital indirect detectors are based on the utilization of a complementary metal-oxide semiconductor (CMOS) array with different scintillating screens such as CsI, Gadox. Currently, a CMOS-based indirect X-ray imaging sensor with...
Silicon carbide (SiC) devices have gained much attention owing to their superior characteristics that make them high-temperature, and radiation-hard applications. The advantage of SiC arises from its unique combination of electronic and physical properties such as wide band-gap, high breakdown electric field strength, high saturated electron velocity, and high thermal conductivity. The wide...
X-ray computed micro-tomography (ยต-CT) is one of the most advanced and common non-destructive techniques in the field of medical imaging and material science. It allows recreating virtual models (3D models), without destroying the original objects, by measuring three-dimensional (3D) X-ray attenuation coefficient maps of samples on the (sub) ยตm scale. The quality of the images obtained using...
CO2 is widely used as the quenching agent in detectors used in high-energy physics due to its good features of stabilizing the electrons avalanche development. Also, the life time is two orders of magnitude higher than for mixtures with an organic quenching agent. In detectors used for precise measurements of particle tracks (i.e. vertex detectors)with an accuracy of less than 50 ยตm, CO2 ...
Detectors with high radiation tolerance and high time resolution are required for charged particle in high physics and space applications.
3D detectors were introduced by S. Parker [1] in the middle 90โ and they represented a starting point for evolved device able to work at fluency up to $2 \times 10^{16}$ $n_{eq}/cm^2$. A limit to 3D detector is the not uniformity of electrical field that...
Synchrotron based Low Energy X-ray Fluorescence (XRF) spectroscopy is one of the most widely used non-destructive techniques for elemental analysis in many fields; from biomedical to electrochemical. Even if XRF emission is an isotropic phenomenon, the specimen inhomogeneities may exhibit angular dependence. Despite the modern understanding of the technique, angular dependence artifacts remain...
The silicon strip sensors are heavily employed in the high energy physics experiments owing to their excellent performance in tracking and vertexing of incoming particles in the radiation environment. However, as these sensors have to be operated in intense radiation environment with unprecedented luminosity, they would undergo both surface and bulk radiation damage. The requirement of...
With increasing demand for high-resolution X-ray images, the super-resolution method allows to estimate a single high-resolution image from several low-resolution images. Hybrid pixel detectors provide high-quality and low-resolution images, which makes them particularly well suited for super-resolution. However, such detectors consist of a limited number of pixels at high cost.
Applying...
Advances in pixellated Silicon sensors - be they hybrids or monolithic - are ubiquitous and rapid. More and more complex systems often take several development iterations before they reach maturity in the context of their often specialized applications. For some applications, namely measurements of UV or soft X-ray photons, or imaging of low- energy charged particles, an added challenge makes...
Material decomposition of sample components can be performed using multi-energy or multi-threshold X-ray imaging. The hybrid semiconductor photon counting pixel detectors of the Medipix family are highly convenient for this application as they enable dual- or multi-threshold imaging (Medipix3) or fully spectral imaging (Timepix3). We have proven that various types of materials can be...
Beam luminosity increasing leads to the fact that undesirable deviations from the trajectory can lead to catastrophic consequences for any deflecting and measuring systems. To prevent such incidents, the BRIL team has developed the BCML system, which allows to dump the beam in a short time if a certain dangerous level of luminosity is exceeded. To this system the many requirements applying...
Recent progress in the field of high energy physics and in space applications brings detector utilization in a radiation harsh environment where also high-energy electrons play an important role, like radiation belts of planets or the electron-positron collider foreseen as the ILC. We have been studying the radiation hardness of developed Schottky barrier semi-insulating (SI) GaAs detectors...
We present an application of the PH32 strip radiation detector [1] for a study of runaway electrons [2] in the GOLEM tokamak at the FNSPE CTU in Prague [3]. GOLEM has a chamber $0.8 \;\mathrm{m}$ in diameter and operates in the magnetic field $B_t < 0.5 \; \mathrm{T}$ and the discharge duration is $t \approx 13 \; \mathrm{ms}$. The detector used for diagnostics is composed of the PH32 silicon...
Cargo container inspection system uses megavoltage x-rays to detect illicit objects. We developed dual energy cargo container inspection system to decompose materials with different atomic numbers. The cargo container inspection system developed in this study generates MeV dual energy, 9 MeV and 6 MeV x-rays using a linear accelerator. Also, empirical dual energy calibration algorithm and a...
The PERCIVAL detector is a large Monolithic Active Pixel Sensor (MAPS) dedicated to soft X-ray experiments, in the primary energy range of $250~\rm{eV}$ to $1~\rm{keV}$, for synchrotron and FEL facilities. A first 2 million pixels system is being developed. Its sensitive area is $\sim 4 \times 4~cm^2$ with a pixel pitch of $27~\mu\rm{m}$. Due to the absorption lengths of photons in the soft...
Single photon counting systems offer good position resolution and operation with high X-ray flux, so making a pixel size smaller is a general tendency in such systems. Thanks to the detector technology development based on high Z materials (GaAs, CdTe, CZT, etc.), the hybrid pixel detectors with direct photonโtoโcharge conversion become more and more popular, even in medical applications....
A bone microcrack under physiological condition can be defined as a fissure in the hydroxyapatite matrix caused by damage accumulation over the limit of remodeling process [1]. Microdamage accumulation accelerated by process of aging and metabolic diseases decreases bone strength and finally leads to loose of primal stability and bearing capacity of the bone. Understanding the fatigue cracking...
The presented study concerns the effects of cumulative and transient ionizing radiation damage on the novel monolithic pixel detector, X-CHIP-03 [1], manufactured in a 180 nm SoI technology. The X-CHIP-03 contains analog and digital parts, where the latter includes a long shift register useful for SEE measurements. Its predecessor X-CHIP-2 [2], manufactured in the same SoI technology, contains...
Recently, reactor neutrino experiments have found that the measured reactor antineutrino spectrum disagrees with the reactor flux model prediction. In the energy range of 4-6 MeV, an excess of 10% found in the measured spectrum suggests the prediction of the reactor antineutrino spectrum is incorrect. The reactor antineutrino spectrum and the origins of the disagreement with prediction becomes...
One of the trends in the development of front-end electronics is a digitization of analog signals at the earliest stage, followed by their application specific processing in digital domain. Digital processing allows to filter data, remove uninformative or spoiled data, detect overlays and calculate of peak signal. The processing functions are usually assigned to the remote data acquisition...
Detection of radioactive sources in unconstrained environment with no specific entrance and exit points remains a challenge for nuclear security. The problem is more difficult when it comes to shielded radiation sources. In this work we present an approach of a sensor network that is composed of small form factor CZT radiation sensors which uses both an analytical algorithm and MVA techniques...
We present first, standalone and autonomous X-ray camera capable of operation 1.2 Mfps. The camera utilizes UFXC32k hybrid pixel detectors for sensing X-rays, FPGA for sensor data acquisition and compression, Real-Time operating system for FPGA control and data streaming to the higher-level system over 1Gbps Ethernet connection. 1.2 M frames per second is achieved in so-called burst mode of...
Multiple wall carbon nanotubes (MWCNT) present advantages for optoelectronic applications such as the large effective photo-collector surface as well as the possibility to tune their band gap and absorbance through the growth parameters.The use of ordered free-standing MWCNTs for photodevices[1] presents advantages, since they have a tunable absorbance depending on their height while their ...
The current generation of noble liquid dark matter detectors is limited by the radioactivity coming from detector materials, mostly from the specially radio-clean PMTs.Alternative large area avalanche photodiodes (LAAPDs), e.g. EXO, have low gain, small area, insensitiveness to low scintillation levels and high cost per unit of area. Large area hybrid vacuum PMTs, such as SIGHT, may be used as...
The wide direct-bandgap AlGaN is one of the most promising materials for fabrication of radiation hard, double response particle detectors for future collider facilities. However, formation of defects during growth and fabrication of AlGaN based devices is unavoidable. Furthermore, radiation defects are formed in detector structures during operation at extreme conditions.
Study of defect...
GaAs was extensively studied for the last 70 years, but still remains the material of choice only in
certain areas (like production of commercial semiconductor lasers). Noticeable advantages of GaAs over Si
for radiation detector manufacturing, such as higher electron mobility (8000 vs 1400 cm2/(Vยทs)), higher
average atomic number (31.5 vs 14) and wider bandgap (1.43 vs 1.12 eV) [1] result...
High resolution energy resolved neutron imaging at pulsed neutron sources enables simultaneous measurement
of transmission spectra in a wide range of energies spanning from meV to tens of keV. The key enabling
technologies needed for this high resolution spectroscopic imaging are bright spallation neutron sources and
novel neutron counting detectors capable of measuring both position and...
