Secondary neutron dose measurements at the DRACO laser-driven ion source

Area of Science:

• Nuclear Physics
• Radiation Detection

Background:

• Laser-driven ion sources produce secondary pulsed neutron and photon radiation.
• Conventional neutron monitors are inadequate for these pulsed environments.
• Accurate characterization of neutron fields is vital for applications such as hadron therapy.

Purpose of the Study:

• To measure parasitic neutron dose at the Dresden Laser Acceleration Source (DRACO).
• To evaluate the performance of specialized neutron REM counters in pulsed fields.
• To demonstrate single-shot neutron dose monitoring capabilities.

Main Methods:

• Parasitic neutron dose measurements using laser energies from 4.5 to 18 J.
• Employed an active extended-range neutron REM counter (LUPIN-II) for pulsed fields.
• Utilized a passive extended-range neutron REM counter (Passive LINUS) for comparison.

Main Results:

• Neutron doses up to 260 nSv per proton bunch were recorded at 2m from the DRACO vacuum chamber.
• Measurements confirmed the pulsed nature of the neutron field with proton cutoff energy around 60 MeV.
• Passive and active measurements showed reasonable agreement, validating the presence of pulsed neutron radiation.

Conclusions:

• The LUPIN-II neutron REM counter can monitor pulsed neutron radiation on a single-shot basis.
• This capability is significant for applications requiring precise dose characterization in pulsed radiation fields.
• The study validates a novel approach for characterizing neutron fields from laser-driven ion sources.