Atomic Physics

Accelerator Based Atomic Physics

Inter University Accelerator Centre

Highly charged ions (HCI) are highly ionized atoms. They occur in nature in solar winds, hot stars, Earth's upper atmosphere, or in earth's atmosphere during thunderstorms. The study of HCI this important for a variety of fields such as astrophysics, plasma physics, accelerator physics, internal fusion, etc. Accelerator-based atomic physics studies involve the study of HCI produced with help of ion accelerators. Some of the key areas in which research is being pursued at IUAC with HCI are beam foil and beam two foil spectroscopy, circular Rydberg states, lifetime, high-resolution multi-channel Doppler tuned x-ray spectroscopy, Surface effect on post foil charge state distribution, etc..

we aim to look for the links of physics of highly charged ions produced with the ion accelerators and in various nuclear reactions with various interdisciplinary areas such as Astrophysics, ion-energy loss physics, nuclear physics, and plasma physics within the university system. The Ph.D. students from the center as well as the universities are involved in this drive. We educate the students about the various opportunities for physics research with the highly charged ions and interdisciplinary physics. The students are free to select one topic for the thesis problem. We continuously inspire them throughout their studies. Interdisciplinary physics research needs to employ the experimental techniques of different fields and we keep on adding them with our experimental facilities. The strive is being put on for the research on highly charged ions produced from the free-electron laser also.

The interdisciplinary physics research explores the connections between ideas and concepts across the area boundaries within a discipline. Researchers working in different areas can apply the knowledge gained in one area to another area as a way to expand the learning experience. The most effective approach to interdisciplinary physics study enables us to build our interdisciplinary pathway by choosing a research topic that even looks absurd the to the onset. It is not too difficult to find a theme that crosses over disciplinary areas within a subject. However, one of the biggest barriers to achieving true interdisciplinary study in physics is the necessity for collaboration of researchers in different areas. This is difficult, but not impossible. Interdisciplinary research is maximized when professionals from different areas work together to serve a common goal and to help the researchers make the connections between different subject areas. Such interaction lies in the constructive paradigm, which allows constructing new knowledge and a deeper understanding of ideas than the studies of a particular area of physics.

Contact Persons

Dr. Rajesh Pratap Singh Accelerator Based Nuclear Physics Scientist - G

(Lab incharge)

Office : 321, 8595417662

rajeshpratap07@gmail.com

Mr. Deepak Kumar Swami Accelerator Based Atomic Physics Scientist - C

Office : 8207, 9555638289

deepak37swami@gmail.com

Facilities

General Purpose Atomic Physics Chamber (GPAC)

GPAC is a stainless steel vessel installed at 30 degrees in one beamline of beam hall-2 at IUAC. The height of the chamber is 316 mm and its internal diameter is 356 mm. The chamber mounted on rigid raw steel support was designed to carry out atomic physics experiments. The essential features of the chamber include :

Computer controlled movable foil setup mounted on the horizontal rail that can be used for standard time of flight experiments
An arrangement for holding multiple foils in a ladder is made.
Two x-ray detectors can be simultaneously mounted at right angles to the beam axis to observe the decay of excited states in the post-foil beam.
The chamber has an exit port for the post foil beam which facilitates the further study of the post-foil beam by using an Electrostatic analyzer and position sensitive detector for post foil charge state analysis.
The base and the top flange of the chamber has M6 tapped holes at 15 degrees to mount different experimental accessories like mounting arrangement for SSBD detectors.
Chamber has been coupled with a dedicated 250 l/s turbo-molecular pump to achieve 10-7 mbar vacuum within two hours

Straight and Inclined Electrostatic Analyser

Knowledge of post foil charge state distribution is always useful in selecting the beam energy for a particular charge state of interest with maximum yield. For studying the charge state fraction in post foil, we are in the process of developing a new technique involving an Inclined and Straight Electrostatic Analyser (ISESA) in which one plate is held parallel and the other kept inclined at a certain angle relative to the beam axis in beam hall -2. Therefore an ISESA is asymmetric about the beam axis. It is essential to apply the voltages to the plates in such a manner that the beam is deflected towards the inclined one. A small gap (10mm) between the plates at the entry causes large deflections due to the high field. As the ions move forward, the gap increases (causing a lower field) so that the ions can escape without hitting the plate. This inclination of one deflecting plate allows better resolution of charge states and increases the number of charge states escaping without hitting the plate also. Two beam collimating slit systems are placed to align the beam with the axis of the ISESA. ISESA is being used to deflect the post foil charge state so that deflected ions in the field region do not hit the plate at the exit. A trapper drift tube chamber of 1.5 m long is used to transfer ions tangentially after passing the ISESA. The trapper drift tube chamber provides an opportunity to place a 220 mm long Position Sensitive Proportional Counter (PSPC). A P-10 gas-filled PSPC is used to measure the position of different charge states simultaneously. There is one viewport at the end of the beamline and the insertable Faraday cup placed at the end of the vacuum chamber is used to monitor the beam current throughout the experiment. A vacuum control system has been designed to create a high vacuum inside the trapper drift chamber and ISESA. To achieve the desired vacuum, one turbopump (300 l/sec) is employed on the trapper drift tube chamber. To measure the vacuum inside the ISESA, a Pirani gauge and a full range cold cathode gauge are used more...

Multi Channel Doppler Tuned Spectroscopy

Doppler Tuned Spectrometer is a novel spectrometer for X-ray emitting from fast foil excited ion beam. The spectrometer makes use of a large Doppler shift to bring the emission spectrum into coincidence with known features (such as k-edge) of the absorption spectrum of suitable filter material. Tuning is accomplished by varying the angle between the beam and the detector, with the filter material between the source foil and detector. Knowledge of the beam velocity, angle, and absorption spectrum of the filter is sufficient to determine the emission spectrum from the beam. A long one-dimensional position-sensitive proportional counter is used as an X-ray detector in this setup. Position sensitive proportional counter with a single anode wire was tested for X-ray detector by utilizing high-pressure counting gas, up to 1 atm. As a position sensing electrode, a flat-cathode with a backgammon pattern is employed. The position readout has successfully been performed to provide the position resolution of 591 μm for 5.9 keV X-rays with the use of 900 bar at 1550 voltage. A unique Soller slit assembly coupled with a long one-dimensional position-sensitive proportional counter enables us to get distinct x-ray peaks at different angles, which allows us to cover a large number of angles in one shot. A lifetime setup is also used. more...

Life time setup

The lifetime setup for standard beam-foil and beam-two-foil spectroscopy is used in GPAC. The setup gives 100 mm of flight length giving access to a lifetime study of metastable states. Three actuator motors are used to make the target move linear. The least number of these motors is 1 µm. A recent experiment carried out include the lifetime study of metastable states of highly charged Titanium ions at various beam energies.

General purpose atomic physics chamber in beam hall-II

Straight and inclined electrostatic analyzer in beam hall-II

Multi channel doppler tuned spectroscopy setup inside GPSC

Publications

Experimental evidence of beam-foil plasma creation during ion-solid interaction, Prashant Sharma and Tapan Nandi, PHYSICS OF PLASMAS 23, 083102 (2016), Link
Development of a multipurpose beam foil spectroscopy set-up for the low cross-section measurements, Gaurav Sharma, T. Nandi, H.G. Berry, Nitin K. Puri, Nuclear Instruments and Methods in Physics Research B 380 (2016) 26–3
X-ray spectroscopy: An experimental technique to measure charge state distribution during ion–solid interaction, P. Sharma and T. Nandi, Phys. Lett. A 380, 182–187 (2016), Link
Theoretical studies on shaking processes in nuclear transfer reactions, Prashant Sharma and Tapan Nandi, Nuclear Physics A 941 (2015) 265–272, Link
Emerging perspectives of beam-foil spectroscopy, Adya P. Mishra and Tapan Nandi, ScienceJet 2015, 4: 149
Combined Effect of Cascade through circular Orbits and Stark Quenching on the Decay of n=2 to n=1transition of H- like Fe in Beam Foil Excitation, Yogesh Kumar, Adya Mishra and T. Nandi, JQSRT 148, 22-26 (2014), Link
Resonance in the population of circular Rydberg states formed in beam-foil excitation, A.P. Mishra, T. Nandi and B.N. Jagatap, JQSRT, 120 ,114 (2013), Link
Fast Ion Surface Energy Loss and Straggling in the Surface Wake Fields, T. Nandi, K. Haris, Hala, Gurjeet Singh, Pankaj Kumar, Rajesh Kumar, S.K. Saini, S.A. Khan, Akhil Jhingan, P. Verma, A. Tauheed, D. Mehta, H.G. Berry, PRL 110, 163203 (2013), Link
Radiative resonant energy transfer process in projectile-like ion formed in beam-foil interaction, A.P. Mishra, T. Nandi and Jagatap, JQSRT, 118, 70 (2013), Link
Radiative resonant energy transfer: A new excitation mechanism in beamfoil interaction, T. nandi,Mumtaz Oswal, Sunil Kumar, Akhil Jhingan, S.R. Abhilash, S. Karmakar, JQSRT (Letter) , (2012), Link
Lifetime of 1s2s2p ⁴P⁰_5/2 in V²⁰⁺ using beam-foil technique, T. Nandi, P. Marketos, P. Joshi, R.P. Singh, C.P. Safvan, P. Verma, A. Mandal, A. Roy and R.K. Bhowmik, Phys. Rev A 66, 052510 (2002), Link
Role of Ion-Surface Interaction at the Entry Surface on the Energy Loss of Highly Charged Slow Ions in Solids, Tapan Nandi, Open Journal of Microphysics, 2011, 1, 53-57, Link
Observation of transitions involving core-excited states in Ar III & Ar IV and high-lying singly excited states in Ar IAr IV, T. Nandi, A.P. Mishra, B.N. Jagatap, JQSRT 112, 221-2778 (2011)
Measurement of wakefield intensity, T. Nandi and B.P. Mohanty, J. Phys. B 42, 225402-5 (2009), Link
Experimental confirmation of Circular Rydberg states with projectile like ions, T. Nandi, J. Phys. B 42, 125201-4(2009)
Collision-induced intra-shell transitions in He-like ions, T. Nandi, J. Phys. B 42, 061002 (2009) (Fast Track Communication)
Effect of satellite lines on the 1s2p 3Po 2 level lifetimes in He-like ions, T. Nandi, JQSRT, 109, 2725-2730(2008)
Formation of the circular Rydberg states in ion-solid collisions, T. Nandi, Astrophys. J., 673, L103-L106(2008)
Comparison of experimental and theoretical efficiency of HPGe X-ray detector, B.P. Mahanty, P. Balouria, M.L. Garg, T. Nandi, V.K. Mittal, and I.M. Govil, Nucl. Instr. Meth. 584, 186-190 (2008)
Selective population of the 1s2s ¹S₀ and 1s2s ³S₁ states of He-like uranium, J. Rzadkiewicz, Th. Sthlker, D. Bana, H. F. Beyer,1 F. Bosch, C Brandau, C. Z. Dong, S. Fritzsche, A. Gojska, A. Gumberidze, S. Hagmann, D. C. Ionescu, C. Kozhuharov, T. Nandi, R. Reuschl, D. Sierpowski, U Spillmann, A. Surzhykov, S. Tashenov, M. Trassinelli, and S. Trotsenko, Phys. Rev. A 74, 012511-16 (2006)
Beam-single and beam-two-foil experimental facility to study physics of highly charged ions, Nissar Ahmad, A. Wani, R Ram, S Abhilash, Rakesh Kumar, J K Patnaik, Sankar De, R Karn, Tapan Nandi, Rev. Sci. Instru. 77, 033107-11(2006)
Reliable measurement of the Li-like ₂₂Ti⁴⁸ 1s2s2p ⁴P^o_5/2 level lifetime by beam-foil and beam-two-foil experiments, T. Nandi, Nissar Ahmad, A.A. Wani, P. Marketos, Phys. Rev. A. 73, 032509-14(2006)
L x-ray production in ⁵⁷La, ⁵⁸Ce, ⁶⁰Nd and ⁶²Sm by 35.60 MeV carbon and oxygen ions, R. Mehta, N.K. Puri, Ajay Kumar, A. Kumar, B.P. Mahanty, P. Balouria, I.M. Govil, M.L. Garg, T. Nandi, A. Ahamad and G. Lapicki, Nuclear Inst. and Methods in Physics Research, B241 63-68(2005)
Lifetime of 1s2s2p ⁴P⁰₅_/₂in Ti¹⁹⁺by beam-foil and beam-two-foil experiments, T. Nandi, Nissar Ahmad, A.A. Wani, and P. Marketos, Phys. Rev. A.72, 022711-16(2005)
Inclined plate electrostatic charge state analyzer , T. Nandi, Nissar Ahmad, Hemant K. Singh, and R.G. Pillay., Rev. Sci. Instr. 75, 5041-5043(2004)
Lifetime of 1s2p 3Po 2 using Beam-two-foil experiments, T. Nandi, A.A. Wani, Nissar Ahmad, P. Marketos, R.P. Singh, R. Ram,and S. Ahmad, J. Phys.B.37 703-710 (2004)
Lifetime of 1s2s2p ⁴P^o _5/2 using Beam-foil techniques , T. Nandi, P. Marketos, P. Joshi, R.P. Singh, C.P. Safvan, P. Verma, A.Mandal, A. Roy,and R.K. Bhowmik Phys. Rev. A 66, 052510-15(2002)
K and L x-ray production cross sections and intensity ratios of rare earth elements for proton impact in the energy range of 20-25 MeV, M Hajivaliei, Sanjiv Puri, M.L. Garg, D. mehta, A. Kumar, S.K. Chamoli, D.K. Avasthi, A. mandal, T. Nandi, K.P. Singh, Nimal Singh, I.M. Govil, Nucl.Instru.Meths. B160 203-215 (2000)
Lifetimes of some O II levels by beam-foil experiments , T. Nandi, P. Marketos, N. Bhattacharya, and S.K. Mitra., J. Phys.B 32 769-778(1999)
Study of secondary electron emission from various targets due to 100 MeV Si⁷⁺ ions, R.S. Chauhan, V.K.Mittal, T. Nandi, A.Mandal, and D.K. Avasthi, Vacuum 48, 1031(1998)
Theoretical Lifetimes for Certain O II Levels P.Marketos and Tapan Nandi, Z. Phys. D42, 237-242 (1997)
L-shell Ionization Studies of Au with _-particle and Lithium Ion Bombardments, B.B. Dhal, Tapan Nandi, H.C. Padhi, and D. Trautmann, J. Phys.B28 3559-68 (1995)
Experimental Evidence in Favour of Stark Mixing of Atomic L-subshell States in Boron Impact of Au and Bi, H.C. Padhi, B.B. Dhal,Tapan Nandi, and D. Trautmann, J. Phys.B28 L59-L63(1995)
L-shell Ionization Studies of Au and Bi with by 4.8-8.8 MeV Boron Ion Bombardment, B.B. Dhal, Tapan Nandi, and H.C. Padhi, Nucl. Instr. Meth. B101, 327-34 (1995)
L-shell Ionization Studies of Pb and Bi with alpha-particle, B.B. Dhal,Tapan Nandi, and H.C. Padhi, Phys. Rev.A49 329-36(1994)
Spectroscopy of Highly Excited States in Na II-IV ions, Tapan Nandi, M.B. Kurup, K.G. Prasad, and P. Marketos, J. Phys.B28 685-92(1995)
Study of Core Excited States in Neutral Na, Tapan Nandi, M.B. Kurup, K.G. Prasad, and P.M.R. Rao, J. Phys. B27 1975-80(1994)
Lifetimes and Excitation Functions of Levels in Ar II-IV, Tapan Nandi, M.B. Kurup, K.G. Prasad, P.M.R. Rao, S. Padmanabhan, G. Krishnamurthy and A.P. Mishra, JQSRT 49 389-400 (1993)