S. A. Shulyapov, E. M. Starodubtseva, I. N. Tsymbalov, A. Yu. Zavorotny, M. A. Bakulev, A. S. Chepurnov, A. A. Kuznetsov, A. B. Savel'ev, “Measurement of the energy spectrum of short-pulse neutron sources based on photonuclear reactions”, Pis'ma v Zh. Èksper. Teoret. Fiz., 2025, Volume 121, Issue 11,Pages <nobr>865

FIELDS, PARTICLES, AND NUCLEI

Measurement of the energy spectrum of short-pulse neutron sources based on photonuclear reactions

S. A. Shulyapov^a, E. M. Starodubtseva^a, I. N. Tsymbalov^ba, A. Yu. Zavorotny^a, M. A. Bakulev^ca, A. S. Chepurnov^ca, A. A. Kuznetsov^ca, A. B. Savel'ev^da

^a Faculty of Physics, Moscow State University, Moscow, 119991 Russia
^b Institute for Nuclear Research, Russian Academy of Sciences, Moscow, 117312 Russia
^c Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, 119991 Russia
^d Lebedev Physical Institute, Russian Academy of Sciences, Moscow, 119991 Russia

Abstract: The energy spectrum of neutrons generated in the Pb($\gamma ,n$) photonuclear reaction has been experimentally studied using a short-pulse laser-plasma electron source (1 TW, 10 Hz). An electron beam accelerated in a nitrogen jet is incident on a lead converter where bremsstrahlung initiating a photodisintegration reaction is generated. The time-of-flight method has been applied for the first time to measure the neutron spectrum in the neutron-counting mode using a scintillation detector based on a stilbene crystal. An exponential distribution with a characteristic “temperature” of $\sim$ 2 MeV and a maximum energy of $\sim$ 8 MeV is observed in the measured spectrum. The developed method is very promising for studying photonuclear reaction cross sections near the threshold using compact laser systems or projected $\gamma $-ray sources based on inverse Compton scattering.

Received: 20.04.2025
Revised: 29.04.2025
Accepted: 30.04.2025

DOI: 10.31857/S0370274X25060019