The upcoming 50 kt magnetized iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) is designed to study the atmospheric neutrinos and antineutrinos separately over a wide range of energies and path lengths. The primary focus of this experiment is to explore the Earth matter effects by observing the energy and zenith angle dependence of the atmospheric neutrinos in the multi-GeV range. This study will be crucial to address some of the outstanding issues in neutrino oscillation physics, including the fundamental issue of neutrino mass hierarchy. In this document, we present the physics potential of the detector as obtained from realistic detector simulations. We describe the simulation framework, the neutrino interactions in the detector, and the expected response of the detector to particles traversing it. The ICAL detector can determine the energy and direction of the muons to a high precision, and in addition, its sensitivity to multi-GeV hadrons increases its physics reach substantially. Its charge identification capability, and hence its ability to distinguish neutrinos from antineutrinos, makes it an efficient detector for determining the neutrino mass hierarchy. In this report, we outline the analyses carried out for the determination of neutrino mass hierarchy and precision measurements of atmospheric neutrino mixing parameters at ICAL, and give the expected physics reach of the detector with 10 years of runtime. We also explore the potential of ICAL for probing new physics scenarios like CPT violation and the presence of magnetic monopoles. v Physics Potential of ICAL at INO vi PrefaceThe past two decades in neutrino physics have been very eventful, and have established this field as one of the flourishing areas of high energy physics. Starting from the confirmation of neutrino oscillations that resolved the decades-old problems of the solar and atmospheric neutrinos, we have now been able to show that neutrinos have nonzero masses, and different flavors of neutrinos mix among themselves. Our understanding of neutrino properties has increased by leaps and bounds. Many experiments have been constructed and envisaged to explore different facets of neutrinos, in particular their masses and mixing.The Iron Calorimeter (ICAL) experiment at the India-based Neutrino Observatory (INO) [1] is one of the major detectors that is expected to see the light of the day soon. It will have unique features like the ability to distinguish muon neutrinos from antineutrinos at GeV energies, and measure the energies of hadrons in the same energy range. It is therefore well suited for the identification of neutrino mass hierarchy, the measurement of neutrino mixing parameters, and many probes of new physics. The site for the INO has been identified, and the construction is expected to start soon. In the meanwhile, the R&D for the ICAL detector, including the design of its modules, the magnet coils, the active detector elements and the associated electronics, has been underway over the past deca...

Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN), a plastic scintillator array (10×10), is being constructed for the purpose of electron anti-neutrino (ν e ) detection for reactor monitoring applications. A prototype detector called mini-ISMRAN, which consists of 16% of ISMRAN, has been setup for studying the detector response, background rates and event characterization in the reactor and non-reactor environment. The data acquisition system based on waveform digitizers is being used for pulse processing and event triggering. Monte-Carlo based simulations using GEANT4 are performed to optimize lead (Pb) and borated polyethylene (BP) shielding for background reduction and to study the positron, neutron and γ-ray response in the ISMRAN detector. Characterization of plastic scintillator detectors with known radioactive sources is performed for energy, timing and position measurements.Using the energy summation and bar multiplicity selection, coincident events from 60 Co decay are reconstructed in non-reactor environment. Results from background measurements using various detectors are quantified in reactor ON and OFF condition. The shielding of 10 cm Pb and 10 cm BP along with the requirement of hits in multiple bars, reduces the uncorrelated background in reactor ON condition. been shown to be sensitive to the reactor ON and OFF cycles. Also, since the ν e rate and energy spectrum changes as the uranium in the core is consumed and plutonium is produced, it is possible to calculate the burn up and estimate the isotopic content of the core [3]. Several groups across different countries are already pursuing this activity [4,5,6].This technique of monitoring reactors remotely may be useful for the International Atomic Energy Agency's (IAEA) 'Reactor Safeguards Regime' aimed towards ensuring implementation of safeguards for reactor facilities [7].Apart from relatively small volume of the detector, factors such as mobility of the setup, safety and convenience of use, especially, from the point of view of long-term operation are crucial for the goal of reactor monitoring. Due to their chemical composition, LS are toxic, flammable and face issues of compatibility with the container material, as they are good solvents. Plastic scintillators (PS) on the other hand are 98% Polyvinyl chloride (PVC), Polyvinyl Toluene (PVT) or polystyrene i.e. similar to normal plastic with no toxic or radioactive component and non-flammable. Therefore, for long-term near reactor operation use of PS is preferable. However, PS suffers from issues such as reduced light output due to attenuation and radiation damage. These aspects have been extensively studied and addressed to a reasonable extent in modern commercially available PS detectors [8]. Also, majority of PS can not use pulse shape discrimination (PSD) technique for discrimination between neutron and γ-ray signals.However, a segmented geometry of many plastic scintillator bars, employing a thermal neutron capture agent, can make use of the hit patterns and energy deposition ...

An earlier measurement on the 4+ to 2 + radiative transition in 8 Be provided the first electromagnetic signature of its dumbbell-like shape. However, the large uncertainty in the measured cross section does not allow a stringent test of nuclear structure models. The present paper reports a more elaborate and precise measurement for this transition, via the radiative capture in the 4 He+ 4 He reaction, improving the accuracy by about a factor of three. The ab initio calculations of the radiative transition strength with improved three-nucleon forces are also presented. The experimental results are compared with the predictions of the alpha cluster model and ab initio calculations.PACS numbers: 21.60. De, 23.20.Js, 24.30.Gd, 27.20.+n The nucleus 8 Be is a classic example of the occurrence of alpha clustering [1] in nuclei. Its formation from two alpha particles provides an intermediate step in the synthesis of 12 C [2] from the fusion of three alpha particles inside the stars. The nucleus is also the stepping stone to understand alpha-clustering in heavier self-conjugate 4n nuclei. The dumbbell-shaped nucleus exhibits rotational states manifested as resonances in the alpha-alpha scattering system. The electromagnetic transition between the excited resonant states in 8 Be, with spin-parities of 4 + and 2 + , was reported earlier [3] in order to provide a test for its alpha cluster structure. The measurements were made at two beam energies, on and off the 4 + resonance, by detecting the transition gamma rays in coincidence with the two alpha particles arising from the decay of the 2 + final state. However, the measured cross section (with an uncertainty of ∼33%) and the inferred reduced electromagnetic transition rate were not precise enough to provide a stringent test for various models like the cluster model [4] and ab initio quantum Monte Carlo model [5]. The uncertainty arose mainly due to the large background of 4.44 MeV gamma rays originating from the interaction of the incident beam with the window of the chamber holding the helium gas target. The present work, using essentially the same method, is aimed at a more accurate measurement and also at more beam energies straddling the 4 + resonance. The essential aspects in this improved measurement are a better pixelisation of the alpha particle detectors, a more efficient and segmented gamma ray detector and a better shielding of the gamma rays from the beam-window interaction mentioned above.The experiment was carried out using beams of 4 He from the BARC-TIFR Pelletron Linac Facility at TIFR, Mumbai at energies of 19−29 MeV. The beam current was about 1 pnA on the target. The schematic of the experimental setup is shown in Fig. 1. The γ-rays were detected in a BGO detector array with a photopeak efficiency of about 23% at E γ =8 MeV. The array consisted of 38 hexagonal cross section detectors, of length 76 mm and a face to face distance of 56 and 58 mm (in two groups), encased in thin aluminum housing. These were mounted in close packed groups of 19 each p...

The damping of the nuclear shell effect with excitation energy has been measured through an analysis of the neutron spectra following the triton transfer in the 7 Li induced reaction on 205 Tl.The measured neutron spectra demonstrate the expected large shell correction energy for the nuclei in the vicinity of doubly magic 208 Pb and a small value around 184 W. A quantitative extraction of the allowed values of the damping parameter γ, along with those for the asymptotic nuclear level density parameterã, has been made for the first time. The shell effect is a cornerstone of the mean field theory describing finite fermionic systems. The shell structure in atoms decides the chemical properties of the corresponding elements. In nuclear physics the spin orbit coupling, in addition, plays a dominant role in deciding the shell closures and the associated magic numbers of protons and neutrons. The nuclei having such numbers of neutrons and protons have an extra stability with respect to that expected from the average behaviour described by the liquid drop model (LDM). Many important nuclear phenomena such as the occurrence of super heavy elements [1,2], fission isomers [3,4], super-deformed nuclei [5] and new magic numbers in exotic nuclei [6,7] are the consequences of the shell effect. The shell effect also affects another fundamental property of the nucleus viz. the nuclear level density (NLD). The NLD is an indispensable input to the statistical calculation of compound nuclear decay and thus an important physical quantity for many practical applications, such as the calculations of reaction rates relevant to nuclear astrophysics, nuclear reactors and spallation neutron sources.The NLD was first calculated by Bethe using a noninteracting Fermi gas model, without shell effects, arriving at its leading dependence on excitation energy (E X ) and angular momentum (J) [8,9]. The generic behaviour with respect to E X is described by e 2 √ aE X . Here 'a' is the NLD parameter which is related to the single particle density at the Fermi energy. Direct measurements of the NLD are based on the study of slow neutron resonances, which are mainly s-and p-wave, and are extrapolated to higher J values to estimate the angular momentum summed or total NLD. The total NLD inferred from such a measurement shows that on the average the level density parameter a increases linearly with the mass number (A) of the nucleus as a ≈A/8 MeV −1 . However, there is a significant departure from this liquid drop value at shell closures. This departure is the largest for the doubly magic nucleus 208 Pb, where a (at E X ∼7 MeV) is as low as A/26 MeV −1 . This shell effect on the NLD parameter is expected to damp with excitation energy so that a approaches its liquid drop value at E X ∼ 40 MeV [10]. It is important to make measurements on the damping of the shell effect over a wide E X range. To our knowledge, no such measurement has been reported.Experimental information on the damping of the shell effect can be obtained by measuring the E X dependence...