LANSCE Neutron Beam Experiment (2025)

Researchers from the MoNA Collaboration, including students and post docs, traveled to New Mexico to test Next Generation Neutron Detector (NGn) prototypes at the Los Alamos Neutron Science Center (LANSCE).

Figure 1: LANSCE celebrated its 50th anniversary in 2022.

Figure 2: Location of the 90 m Station with respect to the neutron production target (Target 4).

The setup was located on a flight path of 90 m from the neutron spallation target that is bombarded with an intense 800 MeV proton beam and produces neutrons with energies up to hundreds of MeV. The neutron beam was tightly collimated to a diameter of 3 mm at the 90-m station, and one prototype detector with 63 SiPM sensors was mounted on a translation stage that was remote controlled to move in the horizontal direction. Different vertical beam positions were achieved by manually adjusting the height of the setup. In addition, two more prototype detectors were mounted in a fixed position downstream of the first detector.

The translation stage was designed and assembled by undergraduate students at Davidson College. Prototype detectors from Virginia State University, Davidson College, and Michigan State University were used in this test.

The collected data will be used to optimize the final detector design. The next generation neutron detector is a collaborative project of Augustana College, Davidson College, Hope College, IndianaWesleyan University, James Madison University, Michigan State University, Wabash College, and Virginia State University and funded by the National Science Foundation [https://www.nsf.gov/awardsearch/showAward?AWD_ID=2320400].

Figure 3: The detector is mounted inside a light-tight wooden box on a translation stage in front of the collimator.

Figure 4: Postdoc Juan Lois Fuentes is adjusting the mount for the stationary detectors.

Figure 5: A 9 by 7 SiPM array detects the scintillation light.

Figure 6: Anthony Kuchera and students R J Devlin and Andrew LaRochelle pose for a selfie in Los Alamos.

Figure 7: In addition to the moveable detector, additional prototypes were mounted stationary at a larger distance from the collimator.

MoNA Collaboration Starts its experimental Program at FRIB

Between June 19-July 1, 2025, the MoNA Collaboration conducted its first experiments at the Facility for Rare Isotope Beams (FRIB) using 144 plastic scintillator bars from the MoNA-LISA modular neutron arrays in combination with the large gap Sweeper magnet in the reconfigured S2 vault. Two experiments were performed:  “Investigating the halo structure of ³⁷Mg” (e23033; Co-PIs: A. Revel, B. Monteagudo Godoy, N. Frank) and “Study of possible p-wave halo in ³⁴Na ground state” (e23068; Co-PIs: B. Monteagudo Godoy, A. Revel, A. Banu). Participation for these experiments included faculty and students from all MoNA Collaborators: Wabash College, James Madison University, Argonne National Lab, Augustana College, Davidson College, Virginia State University, Indiana Wesleyan University, Hope College, Concordia College, Indiana University South Bend, and Michigan State University. Additional external collaborators were also present representing the French Authority for Nuclear Safety and Radiation Protection (ASNR, France), the Research Center for Nuclear Physics, Osaka University (Japan), and Lawrence Berkeley National Laboratory (California). The successful running of this Summer 2025 campaign would not have been possible without the critical contributions from the staff of several FRIB divisions.

The MoNA Collaboration during the Summer 2025 campaign.

MoNA-LISA /Sweeper setup in the S2 vault (picture by Shumpei Noji).

Incident secondary beam PID for e23033.

NGn Prototype Detector Tests at TUNL

A group of 18 MoNA researchers, 10 of them undergraduate students, visited the Triangle Universities Nuclear Laboratory (TUNL) located in Durham, NC, in December of 2024 to test prototype detector configurations of the Next Generation Neutron Detector (NGn). NGn is being developed under an NSF-sponsored major research instrumentation project (award numbers 2320400–2320407).

The goal of the test is to evaluate the position sensitivity of a neutron detector assembled from a plastic scintillator panel equipped with an array of silicon photomultipliers (SiPMs) for light readout. The SiPMs measure small amounts of light produced in the scintillator when neutrons collide with protons and scatter them in the scintillator. Careful analysis of the signals recorded from the SiPMs will determine the position at which the scintillation light was produced and thus where the neutron interacted in the scintillator. Tests were run with two different SiPM arrangements and three different scintillator thicknesses. MoNA Collaborators were supported by TUNL researchers Sean Finch and Forrest Friesen, who prepared neutron beams at energies of 8 MeV and 5 MeV.

Each of the undergraduate students performed mission critical tasks during the experiment, and here’s a list of some of these:

Hanna Gebremariam	Augustana	array assembly, offline data analysis
Mackenzie Lauridsen	Augustana	array assembly, offline data analysis
Luke Dalzell	Augustana	array assembly, offline data analysis
RJ Devlin	Davidson	translation stage, run recording
Mace Mierisch	JMU	array configuration & assembly
Lucas Fisher	JMU	SiPM testing
Jalen Felix	VSU	array cabling & trouble-shooting, offline data analysis
Trinity Allen	VSU	cable labeling & array assembly, offline data analysis
Justin Brown	VSU	array cabling, offline data analysis
Sarah Timothy	VSU	run log information

The data will be analyzed to quantify how accurate the position measurement can be, and this will inform the final design for the detectors, which will be constructed at the collaborating institutions starting in the summer 2025. Once completed, the detectors will be used in experiments at the Facility for Rare Isotope Beams to study rare nuclei that decay via neutron-emission on incredibly short time scales.

Group picture of the research team. From left to right: Nathan Frank (Augustana College), Thomas Redpath (VSU), Sean Finch (TUNL), RJ Devlin (Davidson College), Nico Mendez (MSU), Juan Lois Fuentes (MSU), Anthony Kuchera (Davidson College), Hanna Gebremariam (Augustana College), Andrew Wantz (MSU), Thomas Baumann (MSU), Adriana Banu, Mace Mierisch (James Madison University), Jalen Felix (VSU), Mackenzie Lauridsen, Luke Dalzell (Augustana College), Trinity Allen, Justin Brown, Sarah Timothy (VSU).

Anthony Kuchara (left) and RJ Devlin (right, both Davidson College) mount a detector on the remote-controlled positioning frame.

NGn prototype using an array of detector bricks

Jalen Felix (VSU, left) working with Mackenzie Lauridsen (center) and Hanna Gebremariam (right, Augustana College) to assemble the SiPM array for one of the detector tests.

Thomas Baumann (MSU, left) and Lucas Fisher (JMU, right) test SiPM detector bricks offline.