Plasma and Fusion Research

Volume 18, 2402079 (2023)

Regular Articles

Investigation of Temporal Evolution of Hard X-Ray Spectrum from Neon-Seeded Plasma of ADITYA-U Tokamak
Shishir PUROHIT1,2), Manoj K. GUPTA1), Malay B. CHOWDHURI1), Umesh NAGORA1), Yashika TAUNK1), Abhishek KUMAR1), Kajal GARG1), Surya K. PATHAK1), Kumarpalsinh A. JADEJA1), Rohit KUMAR1), Kumudni TAHILIANI1), Sameer KUMAR1), Kaushal M. PATEL1), Rakesh L. TANNA1), Supriya A. NAIR1), Joydeep GHOSH1,2) and ADITYA-U Team
Institute for Plasma Research, Bhat, Gandhinagar 382428, Gujarat, India
Homi Bhaba National Institute, Training School Complex, Anushakti Nagar, Mumbai 400094, India
(Received 9 January 2023 / Accepted 18 July 2023 / Published 25 September 2023)


The adverse effect associated with runaway electrons (RE) requires the temporal monitoring of the Hard X-ray (HX) spectrum produced by RE. This enables us to know the photon flux corresponding to a particular energy of HX in temporal space. A Lanthanum Bromide (LaBr3)-based HX spectrometer system (80 keV ∼ 5 MeV) is routinely operated on the ADITYA-U tokamak for monitoring the temporal evolution of the HX spectrum. The temporal evolutions of the HX energy having maximum count and the average RE temperature (RE average energy) have been analyzed for the plasmas injected with neon (Ne) impurity. It has been found that peak energy and average runaway energy reduces significantly after the Ne gas puff and this reduction happens when the electron density rises after the Ne gas puff. The RE temperature values were ∼ 620 KeV and 230 KeV before and after the Ne injection, respectively. The spectral shape, in both counts and energy, shrunk drastically, suggesting the reduction of the HX emission after the Ne gas puffing.


ADITYA-U, runaway electron, LaBr3(Ce), neon seeding, runaway electron temperature

DOI: 10.1585/pfr.18.2402079


  • [1] A. Hassanein and V. Sizyuk, Sci. Rep. 11, 2069 (2021).
  • [2] B.N. Breizman et al., Nucl. Fusion 59, 83001 (2019).
  • [3] H. Knoepfel and D.A. Spong, Nucl. Fusion 19, 785 (1979).
  • [4] M. Lehnen et al., J. Nucl. Mater. 463, 39 (2015).
  • [5] S. Purohit et al., Rev. Sci. Instrum. 93, 93512 (2022).
  • [6] V. Plyusnin et al., Nucl. Fusion 46, 277 (2006).
  • [7] R.L. Tanna et al., Nucl. Fusion 62, 42017 (2022).
  • [8] A. Shevelev et al., Nucl. Fusion 61, 116024 (2021).
  • [9] J.R. Martin-Solis et al., Phys. Rev. Lett. 105, 185002 (2010).