Isobutane Gas Research Articles

Performance of gas electron tracking detectors for beta decay studies

At the low-energy frontier, among the experiments testing the Standard Model and searching for new physics, are precision spectrum shape and correlation coefficient measurements in nuclear and neutron beta decay. For identification and 3D-tracking of low-energy electrons, a special type of gas-based detector was designed that minimizes scattering and energy loss. First, the newly developed gas tracker was successfully used to study tiny effects in the beta spectrum shape for allowed Gamow-Teller transitions. The miniBETA spectrometer consists of a hexagonally structured multi-wire drift chamber (MWDC) filled with a mixture of helium and isobutane gas and a plastic scintillator serving as a trigger source and energy detector. The drift time information is used to establish the electron tracks in the plane perpendicular to the wires, while the charge division technique provides spatial information along the wires. Second, inspired by the performance of this spectrometer we are building a Mott polarimeter to be used in the BRAND experiment to study the neutron decay correlation coefficients.

The development of segmented electrode thin-film parallel plate avalanche counter (PPAC)

In order to improve the counting rate and position resolution of the Parallel Plate Avalanche Counter (PPAC) within the Compact Spectrometer for Heavy Ion Experiment, a new strip film-structured PPAC has been developed. The developped PPAC detector consists of three layers of film electrodes. The upper and lower layers which serve as the anodes are comprised of self-developed strip film electrodes, oriented perpendicularly to each other. The middle layer utilizes double-sided aluminized Mylar film as the cathode. There is a 3 mm gap between each layer, and the detector has an effective area of 76 mm× 76 mm. Operating in a low-pressure environment with isobutane gas as the working medium, the performance of the PPAC has been measured using a 5.486 MeV α radiation source. The measurement results indicate that the overall position resolution of the PPAC attains approximately 380 μm, and the position resolution improves to 300 μm when using slit width correction. Finally, the Monte Carlo simulation has been performed to simulate the distribution of electrons generated by the detector's ionization under the same conditions on the anode readout strip. The simulation results closely matches the observed multiplicity of hit anode readout strips in measurement.

Gas electron tracking detector for beta decay experiments

For identification and 3D-tracking of low-energy electrons a new type of gas-based detector was designed that minimizes scattering and energy loss. The current version of the detector is a combination of a plastic scintillator, serving as a trigger source and energy detector, and a hexagonally structured multi-wire drift chamber (MWDC), filled with a mixture of helium and isobutane gas. The drift time information is used to track particles in the plane perpendicular to the wires, while a charge division technique provides spatial information along the wires. The gas tracker was successfully used in the miniBETA project as a beta spectrometer for a measurement of the weak magnetism form factor in nuclear beta decay. The precision of the three-dimensional electron tracking, in combination with low-mass, low-Z materials and identification of backscattering from scintillator, facilitated a reduction of the main systematics effects. The results originate from performance studies with cosmic muons and low-energy electrons (<2 MeV) conducted for several pressures (300–700 mbar) and isobutane content in the gas mixture (10–50%). At certain conditions, a spatial resolution better than 0.5 mm was obtained in the plane perpendicular to the wires, while resolutions of about 6 mm were achieved along wires. Thanks to precise tracking information, it is possible to eliminate electrons and other particles not originating from the desired decay with high efficiency. Additionally, using the coincidence between MWDC and scintillator, background from gamma emission typically accompanying radioactive decays, was highly suppressed. An overview of different event topologies is presented together with the tracker’s ability to correctly recognize them. The analysis is supported by Monte Carlo simulations using Geant4 and Garfield++ packages. Finally, the preliminary results from the 114In spectrum study are presented.

Development of Micro-Pattern Gaseous Detectors for Nuclear Reaction Studies

One of the frontiers of today’s nuclear physics research is the synthesis of Super Heavy Elements (SHE). Fusion-fission dynamics, namely the competition between quasi fission and fusion is one of the key challenges to optimize the SHE. To have an insight into the dynamics, one requires the study of fission fragment mass and angular distribution near barrier energies for heavy-ion induced fission reactions. Recent successful installation of linear accelerators in India offers a unique opportunity to study the dynamics of nuclear reactions and formation process of SHE. For the effective utilization of these current, as well as upcoming facilities, development of novel detectors to study reaction dynamics, formation process of SHE with heavier projectiles and higher beam energies is needed. Gaseous detectors have undergone a rapid improvement in terms of spatial, temporal and energy resolution, rate capability, radiation hardness, ion feedback etc., ushering in a new genre of micro-structured devices based on semi-conductor technology, commonly known as Micro-Pattern Gaseous Detectors (MPGDs). Although many of the MPGD structures were primarily developed for high-rate tracking of charged particles in high energy physics experiments, stability of operation, simplicity of construction and relatively low cost make these detectors suitable for other applications, such as low-energy nuclear physics experiments. The present activities encompass a detailed evaluation of the operational conditions of Micromesh-Multi Wire and THGEM-Multi Wire hybrid detector operated in low-pressure isobutane gas with a view to optimizing their use in the detection of charged particles and fission fragments.

Fe doped ZnO nanostructures prepared via sol-gel dip-coating technique for iso-butane (i-C4H10) sensing

Fe doped ZnO (FZO) nanostructures with varying Fe concentrations say 0, 1, 3, 5, 7, and 9 wt.% were prepared on the glass substrates via the sol-gel dip-coating technique. Effects of Fe-doping concentration on the structural, morphological, optical properties and the response to iso-butane (i-C4H10) gas of ZnO nanostructures were studied. The X-ray diffraction (XRD) analysis showed that Fe doping has a significant effect on particle size, strain, and crystalline quality in the prepared films. Scanning Electron Microscopy (SEM) images of the prepared samples revealed nanoparticles and nanorods formation, with content Fe variation. The Energy Dispersive Spectroscopy (EDS) results confirmed the presence of Zn, O, and Fe elements. UV-Vis absorption measurements showed that the deposited films have a transmittance between 69% and 89%, and the differential optical transmittance plot indicated that the band gap energy decreases with increasing Fe doping ratio. The sensitivity characteristics to iso-butane gas were evaluated as a function of the film composition, operating temperature in the range from 150 to 300 °C, and volume gas concentration from 0.8 to 6.4 Vol.%. The obtained results showed that the iso-butane response, as well as the structural, morphological, and optical properties of ZnO nanostructures, changed with the Fe doping. Also, the iso-butane sensing results evidently showed that the 3 wt.% Fe doped ZnO nanostructure offered a remarkable response of ~ 76.3% with a quick response time of ~ 67 s to 0.8 Vol.% of i-C4H10 at the optimum operating temperature of 250 °C. Therefore, FZO nanostructures produced can be used as a sensor for the detection of iso-butane gas in various industrial and domestic branches.

Properties of carbon-doped GaN using isobutane as a dopant

Carbon doping is an effective method to obtain semi-insulating GaN buffer, which is a necessity to prevent current leakage, in the high-electron-mobility-transistor device structure. The properties of intentionally carbon-doped GaN using isobutane gas as a dopant has been studied in detail. The carbon incorporation efficiency has been measured by secondary ion mass spectrometry. It is found that the carbon concentration could be directly controlled by the flow rate of isobutane precursor. The surface morphology of carbon-doped gallium nitride epitaxial layers has been investigated by optical microscopy and atomic force microscopy. The growth mode of GaN layers changes from step-flow to island growth, when the incorporated carbon concentration is higher than 1×1019 cm-3. In order to evaluate the structural quality of intentionally carbon-doped GaN, the full-width-at-half-maximum values are extracted from the rocking curves in six different reflections measured by high resolution X-ray diffraction. Raman spectroscopy is utilized to evaluate the physical properties of the carbon-doped GaN epitaxial layer.

Isobutene production in Synechocystis sp. PCC 6803 by introducing α-ketoisocaproate dioxygenase from Rattus norvegicus

Cyanobacteria can be utilized as a platform for direct phototrophic conversion of CO2 to produce several types of carbon-neutral biofuels. One promising compound to be produced photobiologically in cyanobacteria is isobutene. As a volatile compound, isobutene will quickly escape the cells without building up to toxic levels in growth medium or get caught in the membranes. Unlike liquid biofuels, gaseous isobutene may be collected from the headspace and thus avoid the costly extraction of a chemical from culture medium or from cells. Here we investigate a putative synthetic pathway for isobutene production suitable for a photoautotrophic host. First, we expressed α-ketoisocaproate dioxygenase from Rattus norvegicus (RnKICD) in Escherichia coli. We discovered isobutene formation with the purified RnKICD with the rate of 104.6 ​± ​9 ​ng (mg protein)-1 min-1 using α-ketoisocaproate as a substrate. We further demonstrate isobutene production in the cyanobacterium Synechocystis sp. PCC 6803 by introducing the RnKICD enzyme. Synechocystis strain heterologously expressing the RnKICD produced 91 ​ng ​l−1 OD750−1 ​h−1. Thus, we demonstrate a novel sustainable platform for cyanobacterial production of an important building block chemical, isobutene. These results indicate that RnKICD can be used to further optimize the synthetic isobutene pathway by protein and metabolic engineering efforts.

Facile method for in-situ measurement of gas diffusion coefficient of soil with semiconductor gas sensor and iso-butane gas

Facile method for <i>in-situ</i> measurement of gas diffusion coefficient of soil with semiconductor gas sensor and iso-butane gas

Ultrasonographic Evaluation of Exogenous Isobutane Gas in the Mammary Gland of Cows

Infusion of chemicals or gases into the mammary glands of dairy cattle has been used to alter the appearance of udders in cattle used in exhibitions. People who fit dairy cattle to enhance the gross appearance of the udder by making it appear larger and fuller have used these agents. The ethical issues surrounding this practice are controversial and the purebred dairy cattle show industry is considering methods to detect these practices. In the past, studies using thermography and ultrasonography were inconclusive in determining if agents placed in the udder could be detected.1,2 The purposes of this study were to determine the ultrasonographic appearance of exogenous isobutane gas infused into the udder. And to determine the effects of volume and pressure used to infuse exogenous isobutane gas and exogenous isobutane gas on duration of ultrasonographic appearance in the udder.

Commissioning of the ACtive TARget and Time Projection Chamber (ACTAR TPC)

The ACtive TARget and Time Projection Chamber (ACTAR TPC) is a novel gas-filled detector that has recently been constructed at GANIL. This versatile detector is a gaseous thick target that allows the tracking of charged particles in three dimensions and provides a precise reaction energy reconstruction from the vertex position. A commissioning experiment using resonant scattering of a 3.2 MeV/nucleon 18 O beam on an isobutane gas (proton) target was performed. The beam and the heavy scattered ions were stopped in the gas volume, while the light recoil left the active volume and were stopped in auxiliary silicon detectors. A dedicated tracking algorithm was applied to determine the angle of emission and the length of the trajectory of the ions, to reconstruct the reaction kinematics used to built the excitation functions of the 1 H( 18 O, 18 O) 1 H and 1 H( 18 O, 15 N) 4 He reactions. In this article, we describe the design of the detector and the data analysis, that resulted in center of mass reaction energy resolutions of 38(4) keV FWHM and 54(9) keV FWHM for the proton and alpha channels, respectively.

MRPC3b for CBM-TOF

The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The Multigap Resistive Plate Chamber (MRPC) has been adopted for the construction of the Time of Flight (TOF) Wall; a system time resolution of 80ps is necessary for hadron identification. MRPC3b, as defined in the CBM TOF TDR, has been designed for the outer region of the TOF system. The MRPC3b is a two-stack, 10 gas gaps with 32 strips read out at both ends. The thin floating glass will be used as the electrodes. In this paper, the design details will be discussed. The mass production has already during the spring of 2017. The assembly procedures and QA (Quality Assurance) & QC (Quality Control) methods will also be presented. The performance achieved from the cosmic ray test shows that the efficiency is better than 91% and the resolution is about 80ps with 95% Freon and 5% iso-butane gas mixture.

Selective carbon monoxide sensing properties of bismuth iron oxide

Among nitrogen oxide (NO2), methane (CH4), isobutane (i-C4H10) and carbon monoxide (CO) gases; selective CO sensing has been reported for perovskite p-type bismuth iron oxide (BFO) gas sensor at 200 °C. We have adopted glycine based auto-combustion route to synthesize phase pure BFO powders. For 100 ppm of CO, response% is reported to be 60% with response and recovery times of 85 s and 102 s respectively. BFO sensor yields high sensitivity (n∼ 1.27) and high selectivity with respect to NO2 (selectivity coefficient, κ ∼217.5), CH4 (κ∼994.2) and i-C4H10 (κ∼8.4). The sensor also exhibits excellent repeatability and long-term stability. The selective CO sensing characteristics of BFO sensor has been attributed to the catalytic nature of BFO surface towards efficient CO oxidation. Lower metal-oxygen binding energy, favorable ‘d’ orbital electron configuration of surface iron cations and nature of the surface adsorbed species are demonstrated to be the three dominant parameters in yielding superior catalytic activity towards CO oxidation in order to promote selective CO sensing.

Nano-gate opening pressures for the adsorption of isobutane, n-butane, propane, and propylene gases on bimetallic Co-Zn based zeolitic imidazolate frameworks.

In this article, zeolitic-imidazolate framework-8 (ZIF-8) and its mixed metal CoZn-ZIF-8 were synthesized via a rapid microwave method. The products were characterized by Raman spectroscopy, XPS, XRD, EDX, TEM, NanoSEM, TGA, and DSC. The gas adsorption properties of samples were determined using C3 and C4 hydrocarbons, including propane, propylene, isobutane and n-butane at a temperature of 25 °C. The adsorption equilibrium and kinetics of these gases on various ZIFs were studied. It was noted that ZIF-8 and mixed metal CoZn-ZIF-8 samples start to adsorb these gases after certain pressures which are believed to result in the opening of their nano-gates (i.e., 6-membered rings) to allow the entry of gas molecules. The nanogate opening pressure value (p0) for each ZIF towards different gases was determined by fitting adsorption equilibrium data against a modified form of the Langmuir adsorption isotherm model. It was observed that the value of p0 differs significantly for each gas and to various extents for various ZIFs. Therefore, it is possible that the distinct values of p0 afford a unique technique to separate and purify these gases at the industrial scale. The overall mass transfer coefficient values of the adsorption process were also investigated.

On the nanogate-opening pressures of copper-doped zeolitic imidazolate framework ZIF-8 for the adsorption of propane, propylene, isobutane, and n-butane

In this study, a zeolitic imidazolate framework-8 (ZIF-8) and its copper-doped variants (Cu-doped ZIF-8) were synthesized using a rapid microwave technique. The products were characterized by XRD, NanoSEM, FTIR, Raman spectra, TGA, XPS, and EDX. The gas adsorption properties of samples were performed using C3 and C4 hydrocarbons including propane, propylene, isobutane, and n-butane gases at 25 °C. Both equilibrium adsorption and kinetics were studied. It was found that ZIF-8 and Cu-doped ZIF-8 samples open their nanogates (i.e., six-membered rings) at some threshold pressures when adsorbing different gases, which it is denotes later as the gate-opening pressure (p0). The p0 value for each ZIF toward each gas was evaluated by fitting equilibrium adsorption data against a modified version of the Langmuir adsorption isotherm model. It was observed that the value of p0 differs significantly for each gas utilized, and with different extents for ZIF samples. The overall mass transfer coefficient values of adsorption process were estimated. Therefore, it is possible that the distinct values of p0 afford a unique chance to separate and purify these gases at mass production, and the best-studied adsorbent to for this purpose was Cu30%/ZIF-8.

10Be low-energy AMS with the passive absorber technique

The passive absorber technique is one of the most common ways to suppress the 10B interference during 10Be measurements at facilities working with beam energies above 7 MeV. At lower energies, the range straggling complicates the application of absorbers, so that other suppression techniques are normally preferred. Several experiments were conducted at the SARA (hosted at Centro Nacional de Aceleradores, Seville, Spain) and VERA (Faculty of Physics, University of Vienna, Austria) AMS facilities to demonstrate the potential of the passive absorber technique also at and below 2.4 MeV. Two different absorber setups were installed and tested. For the detection of the rare isotopes both facilities used a gas ionization chamber optimized for light ions detection based on the same design. The absorber installed at the SARA facility was a combination of SiN foils and an isobutane gas volume, whereas VERA was equipped with an absorber constituted of a stack of SiN foils. In both cases, 10Be could be clearly separated from 10B and the use of a passive absorber at the entrance of the detector gave higher transmission compared to the degrader method.Depending on the absorber design, different background contributions could be identified: Rutherford scattering of 10B on the protons contained in the SiN foils and isobutane gas was responsible of a severe background at SARA, and fragments from 9Be1H molecules surviving the stripping process resulted in events partially overlapping the 10Be gate at VERA. The measured transmissions and background levels will be presented for the tested setups, as well as the advantages and disadvantages of each absorber design.

Design and commissioning of a 600 L Time Projection Chamber with Microbulk Micromegas

We report the design, construction, and initial commissioning results of a large high pressure gaseous Time Projection Chamber (TPC) with Micromegas modules for charge readout. The detector vessel has an inner volume of about 600 L and an active volume of 270 L. At 10 bar operating pressure, the active volume contains about 20 kg of xenon gas and can image charged particle tracks. Drift electrons are collected by the charge readout plane, which accommodates a tessellation of seven Micromegas modules. Each of the Micromegas covers a square of 20 cm by 20 cm. A new type of Microbulk Micromegas is chosen for this application due to its good gain uniformity and low radioactive contamination. Initial commissioning results with 1 Micromegas module running with 1 bar argon and isobutane gas mixture and 5 bar xenon and trimethylamine (TMA) gas mixture are reported. We also recorded extended background tracks from cosmic ray events and highlighted the unique tracking feature of this gaseous TPC.

Addressing the selectivity issue of cobalt doped zinc oxide thin film iso-butane sensors: Conductance transients and principal component analyses

Iso-butane (i-C4H10) is one of the major components of liquefied petroleum gas which is used as fuel in domestic and industrial applications. Developing chemi-resistive selective i-C4H10 thin film sensors remains a major challenge. Two strategies were undertaken to differentiate carbon monoxide, hydrogen, and iso-butane gases from the measured conductance transients of cobalt doped zinc oxide thin films. Following the first strategy, the response and recovery transients of conductances in these gas environments are fitted using the Langmuir adsorption kinetic model to estimate the heat of adsorption, response time constant, and activation energies for adsorption (response) and desorption (recovery). Although these test gases have seemingly different vapor densities, molecular diameters, and reactivities, analyzing the estimated heat of adsorption and activation energies (for both adsorption and desorption), we could not differentiate these gases unequivocally. However, we have found that the lower the vapor density, the faster the response time irrespective of the test gas concentration. As a second strategy, we demonstrated that feature extraction of conductance transients (using fast Fourier transformation) in conjunction with the pattern recognition algorithm (principal component analysis) is more fruitful to address the cross-sensitivity of Co doped ZnO thin film sensors. We have found that although the dispersion among different concentrations of hydrogen and carbon monoxide could not be avoided, each of these three gases forms distinct clusters in the plot of principal component 2 versus 1 and therefore could easily be differentiated.

Ionization Quenching Factor measurement of 1 keV to 25 keV protons in Isobutane gas mixture

The French Institute for Radiation protection and Nuclear Safety (IRSN) is providing reference neutron fluence energy distribution at its standard monoenergetic neutron fields, produced at the AMANDE facility. The neutron energy is assessed by measuring the recoil nuclei energy in a μTPC detector, the LNE-IRSN/MIMAC detector. The knowledge of the ionization quenching factor (IQF) is fundamental to determine the kinetic energy of the recoil nuclei. For some various gases and pressures, discrepancies of about 15% were observed between IQF calculations using the SRIM software and experimental measurements. No data are available for the iC4H10 + 50% CHF3 gas mixture which are used for measurements from a few keV up to 565 keV neutron energies in the μTPC detector. The experimental determination of the IQF is of primary importance to provide reference neutron fluence energy distribution. After a short description of the experimental set-up, this paper presents the first results of the IQF measurements in a iC4H10 + 50% CHF3 gas mixture in the energy range 1 keV – 25 keV.

Measurement of positronium thermalization in isobutane gas for precision measurement of ground-state hyperfine splitting

The thermalization parameter of positronium in pure isobutane gas was measured in order to take into account the thermalization effect on precision measurements of the ground-state hyperfine splitting (HFS) of positronium. The momentum-transfer cross section was measured to be for positroniums with kinetic energy below 0.17 eV. Using this value, our new HFS experiment revealed that the positronium thermalization effect on HFS was as large as . In this article, we show the details of Ps thermalization measurement, which have not been published before, and also its effect on HFS.

A new cylindrical drift chamber for the MEG II experiment

A new cylindrical drift chamber is currently under construction for the MEG II experiment. The chamber is meant to track low momentum positrons from μ+ decays to search for μ+→e+γ events. The detector is segmented in very small drift cells, placed in stereo configuration and operated in a helium–isobutane gas mixture. The use of thin aluminium wires and light gas mixture set the total radiation length of the chamber to only 1.6×10−3X0 per track turn allowing for a momentum resolution of ~120keV/c.