arXiv subjects

M. S. Pose

Publications and source records attributed to M. S. Pose.

9 recordsLinked to original sources

arXiv2026

Excitation function for natMo(p,x) reactions with covariance analysis

The excitation functions of proton induced reactions on natMo targets are measured using the activation technique followed by off-line γ-ray spectroscopy with improved precision. The experiment was performed at the BARC-TIFR Pelletron Linac Facility, Mumbai. Thin samples of natMo were irradiated with a proton beam of energies ranging from 13 to 22 MeV for measurements of various (p,x) cross sections, with an emphasis on the production of medical isotopes. The present data for 93mTc and 94gTc address and resolve the discrepancies in the existing data. The 93gTc radioisotope production is extracted with appropriate corrections for 93mTc contribution. While the measured cross sections for the production of 95gTc, 96g+mTc, 99mTc and 99Mo are consistent with the reported data, significant differences are observed for 89g+mZr. A comprehensive uncertainty analysis, including the correlation coefficients of the measured reaction cross sections is also presented.

nucl-ex↗

arXiv2022

An analytical model for electronic noise in a cryogenic bolometer detector readout circuit

This paper presents an analytical model to quantify the measured noise in a cryogenic bolometer readout circuit. The model includes the contributions from the bias resistors and sensor resistors, voltage and current noise of amplifier, and cable capacitance. The model parameters are empirically estimated using frequency domain analysis of the measured noise data of indigenously developed Neutron Transmutation Doped (NTD) Ge sensors. The model is shown to describe noise data for NTD Ge sensors over a wide range of resistances corresponding to temperatures in the range 20 - 70 mK. Relative contributions of different components are discussed and it is shown that the contribution to the overall noise from the differential amplifier at 300 K is the dominant source. It is observed that the amplifier flicker noise is significantly lower than that specified in the amplifier datasheet. The present study also indicates that a desirable value of resistance of NTD sensor (R$_{NTD}$) from noise considerations is $\leq$ 1 G$Ω$ at $sim$ 20 mK.

physics.ins-det↗

arXiv2022

Radiopurity studies of a rock sample from the Aut region

Efforts are underway to set up an underground laboratory in India for rare event studies like double beta decay, dark matter, etc. For such experiments, mitigation of radiation background is of paramount importance and understanding ambient background at the site, originating from the rock, is one of the crucial factors. With this motivation, the radiopurity studies of a rock sample from the potential laboratory site in the Aut tunnel of Himachal Pradesh (India) have been carried out using the TIFR low background experimental setup (TiLES). The concentration of $^{40}$K in Aut rock is observed to be lower by a factor of ~1000 as compared to the samples from BWH (Bodi West Hill), Tamil Nadu (India), current designated site for India-based Neutrino Observatory. The natural radioactive trace impurity $^{232}$Th is lower in the Aut rock, while $^{238}$U is somewhat higher than the BWH rock. Overall, the ambient gamma ray background at Aut is expected to be lower than the BWH, while ambient neutron background is expected to be similar. Further, to assess the neutron-induced long lived activity, fast neutron activation studies have been carried out on the both Aut and BWH rock samples at the Pelletron Linac Facility, Mumbai.

physics.ins-det↗

arXiv2021

Background Estimation Studies for Positron Double Beta Decay

The study of neutrinoless double beta decay has attracted much attention as it can provide valuable information about the mass and the nature of the neutrino. The double beta decay (DBD) itself is also of interest in nuclear physics. While DBD has been observed in about a dozen nuclei, the positron double beta decay ($β^{+}β^{+}$/EC-$β^{+}$) continues to be an elusive. An important signature for $β^{+}β^{+}$ decay is the simultaneous emission of four 511 keV gamma rays and the coincident detection of these gamma rays can improve the measurement sensitivity. This paper presents an estimation of sensitivity for EC-$β^{+}$ and $β^{+}β^{+}$ employing coincidence measurement with two high purity Ge (HPGe) detectors. Simulations for coincident detection efficiency ($ε_c$) of 511 keV gamma rays with two HPGe detectors have been carried out using GEANT4 for different source geometries to optimize the mass efficiency product (M$ε_c$). The source of size $55\,mm \times 55\,mm \times 5\,mm$ (thickness) sandwiched between the front faces of the detectors were found to be optimal for 2 pairs of 511 keV gamma rays in the present detector setup. The coincident background is estimated at the sea level with moderate Pb shielding. With this setup, the sensitivity for T$_{1/2}$ measurement of EC-$β^{+}$ in $^{112}$Sn and $β^{+}β^{+}$ in $^{106}$Cd is estimated to be $\sim$10$^{19}$ - 10$^{20}$ y for 1y of measurement time.

physics.ins-det↗

arXiv2019

Study of the effect of external noise pickups on the performance of a cryogenic bolometer

This paper reports the detailed noise characterization, investigation of various noise sources and its mitigation to improve the performance of a cryogenic bolometer detector. The noise spectrum has been measured for a sapphire bolometer test setup with indigenously developed NTD Ge sensor in the CFDR system at Mumbai. The effect of external noise, arising either from ground loops in the system or from the diagnostic and control electronics of the cryostat, on the performance of a cryogenic bolometer is assessed. A systematic comparison of the influence of different noise pickups on the bolometer resolution is also presented. The best-achieved resolution at 15mK is ~15 keV for heater pulses and appears to be mainly limited by the noise due to the pulse tube cryocooler.

physics.ins-det↗

arXiv2017

Neutron response of PARIS phoswich detector

We have studied neutron response of PARIS phoswich [LaBr$_3$(Ce)-NaI(Tl)] detector which is being developed for measuring the high energy (E$_γ$ = 5 - 30 MeV) $γ$ rays emitted from the decay of highly collective states in atomic nuclei. The relative neutron detection efficiency of LaBr$_3$(Ce) and NaI(Tl) crystal of the phoswich detector has been measured using the time-of-flight (TOF) and pulse shape discrimination (PSD) technique in the energy range of E$_n$ = 1 - 9 MeV and compared with the GEANT4 based simulations. It has been found that for E$_n$ $>$ 3 MeV, $\sim$ 95 \% of neutrons have the primary interaction in the LaBr$_3$(Ce) crystal, indicating that a clear n-$γ$ separation can be achieved even at $\sim$15 cm flight path.

physics.ins-det↗

arXiv2017

Giant Dipole Resonance studies in Ba isotopes at $\textbf{ E/A}\sim$ 5 MeV

Exclusive measurements of high energy $γ$-rays are performed in $\rm ^{124}Ba$ and $\rm ^{136}Ba$ at the same excitation energy ($\sim$ 49 MeV), to study properties of the giant dipole resonance (GDR) over a wider $N/Z$ range. The high energy $γ$-rays are measured in coincidence with the multiplicity of low energy $γ$-rays to disentangle the effect of temperature ($T$) and angular momentum ($J$). The GDR parameters are extracted employing a simulated Monte Carlo statistical model analysis. The observed $γ$-ray spectra of $\rm ^{124}Ba$ can be explained with prolate deformation, whereas a single component Lorentzian function which corresponds to a spherical shape could explain the $γ$-ray spectra from $\rm ^{136}Ba$. The observed GDR width in $\rm ^{136}Ba$ is narrower compared to that of $\rm ^{124}Ba$. The statistical model best fit GDR cross sections are found to be in good agreement with the thermal shape fluctuation model (TSFM) calculations. Further, it is shown that the variation of GDR width with $T$ is well reproduced by the TSFM calculations over the temperature range of 1.1--1.7MeV.

nucl-ex↗

arXiv2016

Characterization of PARIS LaBr$_3$(Ce)-NaI(Tl) phoswich detectors upto $E_γ$ $\sim$ 22 MeV

In order to understand the performance of the PARIS (Photon Array for the studies with Radioactive Ion and Stable beams) detector, detailed characterization of two individual phoswich (LaBr$_3$(Ce)-NaI(Tl)) elements has been carried out. The detector response is investigated over a wide range of $E_γ$ = 0.6 to 22.6 MeV using radioactive sources and employing $^{11}B(p,γ)$ reaction at $E_p$ = 163 keV and $E_p$ = 7.2 MeV. The linearity of energy response of the LaBr$_3$(Ce) detector is tested upto 22.6 MeV using three different voltage dividers. The data acquisition system using CAEN digitizers is set up and optimized to get the best energy and time resolution. The energy resolution of $\sim$ 2.1% at $E_γ$ = 22.6~MeV is measured for the configuration giving best linearity upto high energy. Time resolution of the phoswich detector is measured with a $^{60}$Co source after implementing CFD algorithm for the digitized pulses and is found to be excellent (FWHM $\sim$ 315~ps). In order to study the effect of count rate on detectors, the centroid position and width of the $E_γ$ = 835~keV peak were measured upto 220 kHz count rate. The measured efficiency data with radioactive sources are in good agreement with GEANT4 based simulations. The total energy spectrum after the add-back of energy signals in phoswich components is also presented.

physics.ins-det↗

arXiv2001

Distributed Data Acquisition System for Pachmarhi Array of Cerenkov Telescopes

Pachmarhi Array of \v Cerenkov Telescopes (PACT) consists of a 5$\times$5 array of \v Cerenkov telescopes deployed over an area of 100 $m$ $\times$ 80 $m$, in the form of a rectangular matrix. The experiment is based on atmospheric \v Cerenkov technique using wavefront sampling technique. Each telescope consists of 7 parabolic mirrors mounted para-axially on an equatorial mount. At the focus of each mirror a fast phototube is mounted. In this experiment a large number of parameters have to be measured and recorded from each of the 175 phototubes in the shortest possible time. Further, the counting rates from each phototube as well as the analog sum of the 7 phototubes from each telescope (royal sum) need to be monitored at regular intervals during the run. In view of the complexity of the system, the entire array is divided into four smaller sectors each of which is handled by an independent field signal processing centre (FSPC) housed in a control room that collects, processes and records information from nearby six telescopes that belong to that sector. The distributed data acquisition system (DDAS) developed for the purpose consists of stand-alone sector data acquisition system (SDAS) in each of the four FSPC's and a master data acquisition system (MDAS). MDAS running in the master signal processing centre (MSPC) records data from each of the 25 telescopes. The data acquisition and monitoring PCs (SDAS and MDAS) are networked through LAN. The entire real time software for DDAS is developed in C under $linux$ environment. Most of the hardware in DDAS are designed and fabricated in-house. The design features and the performance of the entire system along with some other auxiliary systems to facilitate the entire observations will be presented.

astro-ph↗