Neutron beams from deuteron breakup at the 88-Inch cyclotron at Lawrence Berkeley National Laboratory

Abstract

Abstract. Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88 Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.

Performance evaluation of an energy tuning assembly for neutron spectral shaping

“…The LBNL 88-Inch Cyclotron is capable of accelerating deuterons up to a maximum energy of 65 MeV with maximum currents on the order of 10 μA [27]. Deuterons, with a neutron separation energy of 2.22 MeV, are weakly bound and will produce neutrons via breakup in the Coulombic field of a heavier nucleus (elastic breakup), proton stripping reactions (inelastic breakup), and pre-equilibrium and evaporation emission from the excited compound nucleus formed by deuteron absorption [28][29][30][31]. Each production mechanism produces neutrons with different angular and energy distributions.…”

“…where is the breakup radius, is the energy of the deuteron, and is the Q value of the reaction, is the atomic number of the target nucleus, and is the elementary charge of a electron (proton) [29,30].…”

“…3 [27]. A Faraday cup was located at the breakup target location shown in Section 3 and equipped with a 4-mm-thick tantalum breakup target placed in the Cave 0 beam line [30,36]. The tantalum target was backed by a 14.5-mm-thick copper cooling assembly with a 38-mmradius cutout centered on the tantalum target.…”

“…Published neutron spectra for 33 MeV deuteron breakup on tantalum (or similar energies) do not address the low energy component (<3 MeV) necessary for this measurement [30,32], so the measured deuteronbreakup source spectrum from this work was used as the initial source term for the ETA performance simulation. The model captures the first five degrees of the source from BLC, and simulations showed that neutrons emitted at angles greater than five degrees from BLC are negligible given the significant collimation and small solid angle subtended by the ETA.…”

Neutron Soft Errors in Xilinx FPGAs at Lawrence Berkeley National Laboratory

“…The Lawrence Berkeley National Laboratory (LBNL) 88" cyclotron currently has tunable broad spectrum neutrons for SEE and plans to add two monoenergetic beams during 2008 [1]. These beams offer experimenters additional resources for testing.…”