Photomultiplier Tube Research Articles

First-principles study of Cs/O deposited Na<sub>2</sub>KSb photocathode surface

Na<sub>2</sub>KSb photocathodes have many applications in vacuum optoelectronic devices, such as photomultiplier tubes, image intensifiers, and streak image tubes for high-speed detection and imaging in extremely weak light environments, due to their advantages of high temperature resistance, small dark current, low vacuum requirement, low fabrication cost and high fabrication flexibility. In addition, this type of photocathode has important application prospect in high brightness accelerator photoinjectors. To guide the fabrication of high-sensitivity Na<sub>2</sub>KSb photocathodes, Na<sub>2</sub>KSb surfaces with different surface orientations and atom terminations are investigated by the first-principles calculation method based on the density functional theory to obtain the most stable and most favorable surface for electron emission. From the perspectives of surface energy, adsorption energy, and work function before and after Cs adsorption, it is revealed that the Na<sub>2</sub>KSb (111) K surface exhibits superior surface stability and electron emission capability. Furthermore, the electronic structure and optical properties of Cs adsorption and Cs/O co-adsorption on the Na<sub>2</sub>KSb (111) K surface under different Cs coverages are analyzed, and the mechanism of Cs/O deposition on Na<sub>2</sub>KSb surface is studied. The adsorption energy of Cs in the Cs/O adsorption model is much larger than that in the single Cs adsorption model, indicating that the adsorption of O atoms on the Na<sub>2</sub>KSb surface can make the adsorption of Cs atoms on the surface stronger, and thus increasing the adhesion of Cs atoms on the surface. After adsorption of Cs on the Na<sub>2</sub>KSb (111)K surface, the surface work function only decreases by 0.02 eV, while the maximum work function decrease for the Cs/O adsorbed surface is 0.16 eV, with the Cs coverage of 2/4 ML and the O coverage of 1/4 ML. The adsorption of Cs/O atoms on the surface facilitates the charge transfer above the surface and results in charge accumulation, which can form the effective surface dipole moment. The magnitude of the surface dipole moment is directly related to the change of work function. Furthermore, through the analysis of the electronic band structure and density of states, it is found that the adsorbed Cs atoms have additional contribution to the band structure near the conduction band minimum. After the introduction of O atoms, the valence band moves up, also the bottom of the conduction band and the top of the valence band become flat. The Cs/O deposition is beneficial to increasing the absorption of near-infrared light on the Na<sub>2</sub>KSb surface, but it will reduce the absorption of ultraviolet light and visible light, and the refractive index will also decrease. This work has a certain reference significance for understanding the optimal emission surface of Na<sub>2</sub>KSb photocathode and the mechanism of surface Cs/O deposition.

Experimental investigations on acoustic-velocity-flame dynamic characteristics of a stratified burner

To reveal the influence of interaction between pilot and main flames on flow and thermo-acoustic instability characteristics, high-frequency measurement devices such as High-Frequency Particle Image Velocimetry (HFPIV), high-speed camera, pressure sensors, and photomultiplier tube were applied to study the acoustic-velocity-flame dynamic characteristics of the stratified burner under ambient temperature and pressure. Results show that the pilot swirling flow significantly influences the acoustic-velocity-flame dynamic characteristics of the stratified burner. When the pilot and main stage are operated with a swirling air jet and swirling flame, the main recirculation zone disappears, the thermo-acoustic instability is strengthened and the frequency of thermo-acoustic instability is locked with the large-scale vortex shedding frequency. When the pilot stage is converted into a swirling flame, the main recirculation zone re-appears down stream of the nozzle outlet, and the high-temperature burned gas is rolled back to improve the combustion stability of the swirling flame. However, in this case, the interaction between the pilot and main flames makes the thermo-acoustic instability frequency not well consistent with large-scale vortex shedding frequency. The interaction between the main stage and pilot stage flames leads to the increase of the flame angle of the main stage. The heat release fluctuation at the flame interaction region is the most intense, and the large-scale vortex in the outer shear layer of the main stage also causes the flame to produce severe oscillation.

Time calibration and synchronization of the scintillation light detection system in ICARUS-T600

The ICARUS-T600 Liquid Argon (LAr) Time Projection Chamber (TPC) is presently taking data in the Short Baseline Neutrino (SBN) program at Fermilab (U.S.A.) to search for a possible LSND-like sterile neutrino signal at Δm 2 ≈ 1 eV2 with the Booster Neutrino Beam (BNB). A light detection system, based on 360 large area Photo-Multiplier Tubes (PMTs), has been realized for ICARUS-T600 to detect VUV photons produced by the passage of ionizing particles in LAr. This system is fundamental for the TPC operation, providing an efficient trigger and contributing to the 3D reconstruction of events. Moreover, since the detector is exposed to a huge flux of cosmic rays due to its shallow depths installation, the light detection system allows for the time reconstruction of events, contributing to the identification and to the selection of genuine neutrino interactions. The correct time reconstruction of events requires the precise knowledge of the delay of each PMT channel and a good synchronization of recording electronics, this last based on fast sampling digitizers. To achieve a time resolution better than 1 ns, we perform three consecutive timing corrections deployed at different stages of the optical data flow. Results demonstrate the capability of the ICARUS-T600 light detection system to allow a precise reconstruction of the temporal evolution of each event occurring in the detector and the association of neutrino events with the bunched structure of BNB.

Analysis of Count Rate Stability Improvement of High-Temperature Photomultiplier Tubes Based on Thermal Cycling Post-Treatment

Analysis of Count Rate Stability Improvement of High-Temperature Photomultiplier Tubes Based on Thermal Cycling Post-Treatment

A large field-of-view angled panel detector for the development of a plant PET system

In plant research, positron emission tomography (PET) is sometimes employed for physiological studies of plants. However, due to the generally high cost of PET systems, their application in plant research centers can be challenging. Furthermore, the configurations of commercial PET systems might not always align well with the requirements of plant research. To address these issues, we have taken the initial steps towards a solution by developing a large field-of-view (LFOV) angled panel detector intended for the development of a plant PET system. This panel detector is composed of two gadolinium orthosilicate (GSO) scintillator blocks, an angled light guide, and four flat panel photomultiplier tubes (FP-PMTs). The GSO pixel size used in the scintillator block measures 2.65 mm (radial)× 2.85 mm (axial)× 15.0 mm, arranged in a configuration of 16 (radial)× 32 (axial) to form a scintillator block with overall dimensions of 44.0 mm (radial)× 94.4 mm (axial)× 15 mm (depth). By implementing an angled light guide, the two scintillator blocks were positioned at a 22.5-degree angle, resulting in the creation of a LFOV angled panel detector. This specific angle allowed for the arrangement of 16 scintillator blocks in a hexadecagonal shape using 8 panel detectors when arranged in a circular configuration. We successfully constructed a panel detector with an approximate field-of-view of 10 cm× 10 cm and conducted a comprehensive performance evaluation. Upon irradiating the panel detector with 511 keV gamma photons, nearly all 1024 GSO pixels were accurately resolved in the position histogram, displaying minimal distortion, and exhibiting an average peak-to-valley ratio of 5.0. Additionally, the energy resolution achieved was 14% full width at half maximum (FWHM). The resulting LFOV angled panel detector holds considerable promise for the use within a cost-effective, user-friendly as well as high performance plant PET system.

METHODS FOR IMPROVING THE DRG-05M DOSIMETER IN BRACHYTHERAPY

Relevance: The article discusses one of the ways to improve the DRG-05M dosimeter in brachytherapy by using new components and technologies in an improved scheme, which includes more accurate sensors, advanced signal processing techniques, efficient power cells, and other solutions. The application of such advanced components and technologies in the framework of DRG-05M dosimeter modernization is a new and original contribution to the field of dosimetry. The scientific novelty of the work is the improvement of the existing circuitry, namely, the improvement of the DRG-05M dosimeter’s electrical circuitry based on the analysis of its shortcomings. This includes replacing components, optimizing circuit structure, eliminating noise and interference, and improving the stability and accuracy of measurements.
 The study aimed to improve the DRG-05M dosimeter to provide more accurate and reliable radiation measurements in brachytherapy.
 Methods: The paper analyses the existing components and their use in the electrical circuit to improve the measurement accuracy of the DRG-05M dosimeter, offers a new electrical circuit based on the collected data and requirements, considering the optimal location of components, their characteristics, performed calculations, and modeled circuit operation. This scientific research was carried out within the framework of the PCF scientific program “Metrological support of dosimetric measurements in contact radiation therapy,” IRN BR12967832.
 Results: We have selected the components for improving the DRG-05M dosimeter:photomultiplier tube (PMT), analog-digital converter (ADC), indication unit, and power supply. The proposed changes to improve the DRG-05M dosimeter shall result in a very compact scintillation-type dosimeter. Its size and weight shall be reduced by at least 3 times; the accuracy and speed of measurement will increase, and the lifetime of the instrument shall improve.
 Conclusion: Improvement of the dosimeter in brachytherapy is an important task to ensure the accuracy and reliability of measurement in treating cancer. Using components such as PMT, calibration source, battery charger, and microcontroller KR572PV5 can significantly improve the operation of the DRG-05M dosimeter and increase the accuracy of radiation dose measurement in brachytherapy.

Study on linearity of photomultiplier tubes by accurately controlling the incident light intensity

Study on linearity of photomultiplier tubes by accurately controlling the incident light intensity

Broadband Cavity-Enhanced Absorption Spectroscopy (BBCEAS) Coupled with an Interferometer for On-Band and Off-Band Detection of Glyoxal.

Glyoxal (CHOCHO) is a trace gas in the atmosphere, often used as an indicator of biogenic emissions. It is frequently compared to formaldehyde concentrations, which serve as indicators of anthropogenic emissions, to gain insights into the characteristics of the environmental source. This study employed broadband cavity-enhanced absorption spectroscopy to detect gaseous CHOCHO, methylglyoxal, and NO2. Two different detection methods are compared. Spectrograph and CCD Detection: This approach involves coupling the system to a spectrograph with a charge-coupled device (CCD) detector. It achieved a 1 min 1-σ detection limit of 2.5 × 108 molecules/cm3, or 10 parts per trillion (ppt). Methylglyoxal and NO2 achieved 1 min 1-σ detection limits of 34 ppt and 22 ppt, respectively. Interferometer and PMT Detection: In this method, an interferometer is used in conjunction with a photomultiplier tube (PMT) detector. It resulted in a 2 min 1-σ detection limit of 1.5 × 1010 molecules/cm3, or 600 ppt. The NO2 2 min 1-σ detection limit was determined to be 900 ppt. Concentrations of methylglyoxal were difficult to determine using this method, as they appeared to be below the detection limit of the instrument. This study discusses the advantages and limitations of each of these detection methods.

Silicon photomultipliers for the SST camera of the Cherenkov Telescope Array

The Cherenkov Telescope Array Observatory (CTAO) will be the major global observatory for gamma-ray astronomy over the next decade and beyond. It will consist of two arrays of telescopes of different sizes, one for each hemisphere, and will be sensitive to gamma rays in the energy range from a few tens of GeV to hundreds of TeV. The Small-Sized Telescopes (SSTs) are a crucial component of the southern array, as they will extend the sensitivity of the observatory to the highest energies. Their focal plane will be equipped with 2048 Silicon Photomultiplier (SiPM) pixels, each one read independently by a state-of-the-art full waveform sampling readout. These solid-state sensors offer advantages over the traditional photomultiplier tubes, such as lower operating voltage, higher photon detection efficiency, and tolerance to bright illumination. In particular, they are the best choice for a small and compact camera such as the SST one. After a detailed comparative study, LVR3-type SiPMs from Hamamatsu Photonics were selected, with an active area of 6 mm × 6 mm, a microcell of 50 μm and without a protective coating, for optimum performance. The sensors demonstrated to have a higher photon detection efficiency and a lower crosstalk compared to the competitors, alongside a low dark count rate. In this contribution, we present the selection process and the latest measurements performed on the SiPMs mounted on the SST Camera module.

Non-Line-of-Sight Atmospheric Optical Communication in the Visible Wavelength Range between UAV and the Ground Surface

An opto-electronic system for non-line-of-sight (NLOS) communication using scattered laser radiation for unmanned aerial vehicle (UAV)–ground and ground–UAV schemes at a wavelength of λ = 450 nm and a ground–UAV scheme at a wavelength of λ = 510 nm are described. The symbol error rate (SER) and its standard deviation were analyzed for different schemes of the communication channel. The transceiver system included a laser source with a power supply, a modulator, a lens refractor, a bandpass filter, a photomultiplier tube (PMT), a demodulator, and a receiving computer. The experimental data obtained at nighttime showed that the NLOS atmospheric optical communication at a wavelength of λ = 450 nm was feasible for the UAV–ground scheme at a baseline distance of up to 150 m for a UAV with a transmitter at a height of 10 m and at a baseline distance of up to 125 m for a UAV at a height of 20 m. For the ground–UAV scheme, stable communication was observed at baseline distances of up to 50 m for a UAV with a receiver at a height up to 30 m. The NLOS atmospheric optical communication at a wavelength of 510 nm was obtained for the ground–UAV scheme at baseline distances of up to 100 m for a UAV with a receiver at a height up to 45 m, as well as at baseline distances of up to 385 m for UAV flying at a height up to 20 m.

Flow cytometry: Aspects and application in plant and biological science.

Flow cytometry is a potent method that enables the quick and concurrent investigation of several characteristics of single cells in solution. Photodiodes or photomultiplier tubes are employed to detect the dispersed and fluorescent light signals that are produced by the laser beam as it passes through the cells. Photodetectors transform the light signals produced by the laser into electrical impulses. A computer then analyses these electrical impulses to identify and measure the various cell populations depending on their fluorescence or light scattering characteristics. Based on their fluorescence or light scattering properties, cell populations can be examined and/or isolated. This review covers the basic principle, components, working and specific biological applications of flow cytometry, including studies on plant, cell and molecular biology and methods employed for data processing and interpretation as well as the potential future relevance of this methodology in light of retrospective analysis and recent advancements in flow cytometry.

Use of Silicon Photomultipliers in the Detectors of the JEM-EUSO Program

The JEM-EUSO program aims to study ultra-high energy cosmic rays from space. To achieve this goal, it has realized a series of experiments installed on the ground (EUSO-TA), various on stratospheric balloons (with the most recent one EUSO-SPB2), and inside the International Space Station (Mini-EUSO), in light of future missions such as K-EUSO and POEMMA. At nighttime, these instruments aim to monitor the Earth’s atmosphere measuring fluorescence and Cherenkov light produced by extensive air showers generated both by very high-energy cosmic rays from outside the atmosphere and by neutrino decays. As the two light components differ in duration (order of microseconds for fluorescence light and a few nanoseconds for Cherenkov light) they each require specialized sensors and acquisition electronics. So far, the sensors used for the fluorescence camera are the Multi-Anode Photomultiplier Tubes (MAPMTs), while for the Cherenkov one, new systems based on Silicon PhotoMultipliers (SiPMs) have been developed. In this contribution, a brief review of the experiments is followed by a discussion of the tests performed on the optical sensors. Particular attention is paid to the development, test, and calibration conducted on SiPMs, also in view to optimize the geometry, mass, and weight in light of the installation of mass-critical applications such as balloon- and space-borne instrumentation.

A feasibility study on distinguishing fluor concentrations in liquid scintillators from scintillation events observed by photomultiplier tubes using convolutional neural networks

A feasibility study on distinguishing fluor concentrations in liquid scintillators from scintillation events observed by photomultiplier tubes using convolutional neural networks

Embedded software of the KM3NeT central logic board

The KM3NeT Collaboration is building and operating two deep sea neutrino telescopes at the bottom of the Mediterranean Sea. The telescopes consist of latices of photomultiplier tubes housed in pressure-resistant glass spheres, called digital optical modules and arranged in vertical detection units. The two main scientific goals are the determination of the neutrino mass ordering and the discovery and observation of high-energy neutrino sources in the Universe. Neutrinos are detected via the Cherenkov light, which is induced by charged particles originated in neutrino interactions. The photomultiplier tubes convert the Cherenkov light into electrical signals that are acquired and timestamped by the acquisition electronics. Each optical module houses the acquisition electronics for collecting and timestamping the photomultiplier signals with one nanosecond accuracy. Once finished, the two telescopes will have installed more than six thousand optical acquisition nodes, completing one of the more complex networks in the world in terms of operation and synchronization. The embedded software running in the acquisition nodes has been designed to provide a framework that will operate with different hardware versions and functionalities. The hardware will not be accessible once in operation, which complicates the embedded software architecture. The embedded software provides a set of tools to facilitate remote manageability of the deployed hardware, including safe reconfiguration of the firmware. This paper presents the architecture and the techniques, methods and implementation of the embedded software running in the acquisition nodes of the KM3NeT neutrino telescopes. Program summaryProgram title: Embedded software for the KM3NeT CLBCPC Library link to program files:https://doi.org/10.17632/s847hpsns4.1Licensing provisions: GNU General Public License 3Programming language: CNature of problem: The challenge for the embedded software in the KM3NeT neutrino telescope lies in orchestrating the Digital Optical Modules (DOMs) to achieve the synchronized data acquisition of the incoming optical signals. The DOMs are the crucial component responsible for capturing neutrino interactions deep underwater. The embedded software must configure and precisely time the operation of each DOM. Any deviation or timing mismatch could compromise data integrity, undermining the scientific value of the experiment. Therefore, the embedded software plays a critical role in coordinating, synchronizing, and operating these modules, ensuring they work in unison to capture and process neutrino signals accurately, ultimately advancing our understanding of fundamental particles in the Universe.Solution method: The embedded software on the DOMs provides a solution based on a C-based bare-metal application, operating without a real-time embedded OS. It is loaded into the RAM during FPGA configuration, consuming less than 256 kB of RAM. The software architecture comprises two layers: system software and application. The former offers OS-like features, including a multitasking scheduler, firmware updates, peripheral drivers, a UDP-based network stack, and error handling utilities. The application layer contains a state machine ensuring consistent program states. It is navigated via slow control events, including external inputs and autonomous responses. Subsystems within the application code control specific acquisition electronics components via the associated driver abstractions.Additional comments including restrictions and unusual features: Due to the operation conditions of the neutrino telescope, where access is restricted, the embedded software implements a fail-safe procedure to reconfigure the firmware where the embedded software runs.

Rooting out ultraweak photon emission a-mung bean sprouts

It is well known that life has evolved to use and generate light, for instance, photosynthesis, vision and bioluminescence. What is less well known is that during normal metabolism, it can generate 1–100 photons s−1 cm–2 known as ultra-weak photon emission (UPE), biophoton emission or biological autoluminescence. The highest generation of these metabolic photons seem to occur during oxidative stress due to the generation and decay of reactive oxygen species (ROS), and their interaction with other components of the cell. To study this further, we have configured a sensitive detection system to study photon emission in germinating mung beans.Here we investigated growing mung beans over 7 days at a constant temperature of 21 ± 1 °C in a light tight box, using dual top and bottom opposing photomultiplier tubes. Over this time period we showed that in total, mung beans grown from seeds generated an average of 5 ± 1 counts s−1 above background. As the new bean stems grew, they showed a gradual linear increase in emission of up to 30 ± 1 counts s−1, in agreement with previous literature. In addition to this “steady-state” emission we also observe delayed luminescence and drought-stress response emission previously observed in other species. Finally, we also observe episodic increased emission events of between 2 and 15 counts s−1 for durations of around 3 h detected underneath the sample, and assign these to the growing of secondary roots.We then induce secondary root formation using aqueous solutions of growth hormones hydrogen peroxide (H2O2, 167 µM) or 3-indole acetic acid (IAA, 0.5 µM) for watering. Both hormones show prolonged increase in emission above steady-state, over days 3–5 with at least 3 times the number of secondary roots formed compared with water alone. We also observed a significant peak increase in photon emission (474 and 1738 cps vs. 28 and 55 cps for water alone) for the H2O2 which we attribute to direct ROS reaction emission as confirmed by measurement on dead plants.Altogether we have expanded upon and demonstrated an instrument and biological system for reliably producing and measuring intrinsic metabolic photons, first observed 100 years ago by Alexander Gurwitsch.

Development of the segmented plastic scintillation detector GARi for studying $r$-process nucleosynthesis at RIBF

\(\beta\)-decay properties of very neutron-rich nuclei, such as the half-life and the \(\beta\)-delayed neutron emission probabilities, play an essential role in the astrophysical rapid neutron capture process (r-process), where elements heavier than iron may be synthesized. Investigating those crucial properties has been one of the main objectives of the experimental programs at the RIKEN RI Beam Factory (RIBF). Recently, the development of a fast-timing detector system comprising a highly segmented plastic scintillation detector GARi (Gas-cell Active detector for Radioisotope decay), a neutron time-of-flight detector array, and a LaBr\textsubscript{3} detector array is being conducted for the measurement of \(\beta\)-delayed neutron emission and other related \(\beta\)-decay properties of neutron-rich nuclei at the F11 decay station of RIBF. The GARi detector has been constructed from a fast, segmented plastic scintillator coupled with nine multi-anode photomultiplier tubes (PMTs), resulting in enhanced position sensitivity. Therefore, this detector can be employed as an implantation detector and can also serve as a trigger signal in neutron time-of-flight experiments. This work details the development of the GARi detector and the results tested with the radioactive sources.

Measurement of PMT charge nonlinearity using the continuous light attenuation method

We use a continuous neutral density attenuator to investigate the photomultiplier tube (PMT) charge nonlinearity which exists in the PMT response to external signals to be measured. The results show that this testing approach provides a reliable and practical method for characterizing the PMT nonlinearity, enabling optimization of the operation conditions and improving the measurement accuracy of PMT by mitigating the nonlinearity. This study helps to advance the research and measurements in the related fields using a PMT.

A multichannel closed bipolar platform to visual electrochemiluminescence sensing of caffeic acid as a model: Potential for multiplex detection

In this study, a fully-featured electrochemiluminescence (ECL) sensing platform based on a multichannel closed bipolar system (closed-BP, C-BP) for the determination of caffeic acid (CA) was successfully developed. The system comprises three individual reservoirs connected to each other by two pairs of gold rods as bipolar electrodes. Moreover, a single pair of gold rods functions as the driving electrodes. Due to configuration consisting of three channels and double-bipolar electrodes, the detection of CA was accomplished in two oxidation and reduction pathways within a single device. Firstly, through close observation of the reactions occurring within the device and utilizing a universal pH indicator and bipolar electrodes, a precise mechanism for the current bipolar systems was initially proposed. Then, the concentration of CA was monitored in the reporting chamber through the following ECL intensities resulting from luminol oxidation and H2O2. The monitoring process was performed using both a photomultiplier tube (PMT) and a digital camera. In the process of analyte oxidation, the PMT and visual (camera)-based detection exhibited a linear response from 5 μmol L−1 to 700 μmol L−1 (limit of detection (LOD) 1.2 μmol L−1) and 50 μmol L−1 to 600 μmol L−1 (LOD 14.8 μmol L−1), respectively. In the analyte reduction pathway, the respective values were 30 μmol L−1 to 450 μmol L−1 (LOD 8.6 μmol L−1) and 55 μmol L−1 to 400 μmol L−1 (LOD 21.2 μmol L−1), for the PMT and visual-based detection, respectively. Our experiments have demonstrated the practical application of the sensor array for efficient and high-performance analysis. This innovative design holds significant potential for diverse fields and paves the way for the development of a user-friendly device.

Multiplex fluorescence detection of single-cell droplet microfluidics and its application in quantifying protein expression levels.

This study presented a platform of multiplex fluorescence detection of single-cell droplet microfluidics with demonstrative applications in quantifying protein expression levels. The platform of multiplex fluorescence detection mainly included optical paths adopted from conventional microscopy enabling the generation of three optical spots from three laser sources for multiple fluorescence excitation and capture of multiple fluorescence signals by four photomultiplier tubes. As to platform characterization, microscopic images of three optical spots were obtained where clear Gaussian distributions of intensities without skewness confirmed the functionality of the scanning lens, while the controllable distances among three optical spots validated the functionality of fiber collimators and the reflector lens. As to demonstration, this platform was used to quantify single-cell protein expression within droplets where four-type protein expression of α-tubulin, Ras, c-Myc, and β-tubulin of CAL 27 (Ncell = 1921) vs WSU-HN6 (Ncell = 1881) were quantitatively estimated, which were (2.85 ± 0.72) × 105 vs (4.83 ± 1.58) × 105, (3.69 ± 1.41) × 104 vs (5.07 ± 2.13) × 104, (5.90 ± 1.45) × 104 vs (9.57 ± 2.85) × 104, and (3.84 ± 1.28) × 105 vs (3.30 ± 1.10) × 105, respectively. Neural pattern recognition was utilized for the classification of cell types, achieving successful rates of 69.0% (α-tubulin), 75.4% (Ras), 89.1% (c-Myc), 65.8% (β-tubulin), and 99.1% in combination, validating the capability of this platform of multiplex fluorescence detection to quantify various types of single-cell proteins, which could provide comprehensive evaluations on cell status.

Characterization study of NaI(Tl) γ-summing spectrometer

The accurate information regarding the β-decay half-life, feeding pattern from the neutron-rich nuclei have utmost importance in the field of nuclear waste management from the fission reactors as well as correct understanding about the r-process nucleosynthesis in stellar sites. The low capture cross-section measurements are also considered as major task by experimental nuclear astrophysicists. These kinds of measurements are really difficult with conventional high-resolution gamma spectroscopy techniques due to less efficiency of the detectors. For this purpose, we have an almost 4π γ-summing NaI(Tl) spectrometer at SINP, Kolkata. It is basically a cylindrical shaped detector with six sectors of NaI(Tl) crystals read by 6 photomultiplier tubes (PMT) at one end. The detailed characterization of the spectrometer via experiment using laboratory standard sources and GEANT4 simulation model to interpret all the interesting properties will be presented here in this paper.