21-29 July 2022
US/Pacific timezone

A segmented total energy detector (sTED) for (n, γ) cross section measurements at n_TOF EAR2

28 Jul 2022, 09:02
Folsom ()



Victor Alcayne (CIEMAT (Spain))


A segmented total energy detector (sTED) for (n, γ) cross section measurements at n_TOF EAR2

V. Alcayne1, D. Cano-Ott1, E. González-Romero1, T. Martínez1, E. Mendoza1, A. Sánchez-Caballero1, J. Balibrea2, C. Domingo-Pardo2, J. Lerendegui2 and n_TOF collaboration3
1CIEMAT, Spain
3CERN, Switzerland

The neutron time-of-flight facility n_TOF [1] is characterised by its high instantaneous neutron intensity, high-resolution and broad neutron energy beams, especially conceived for neutron-induced reaction cross sections measurements. Two TOF experimental areas are available at the facility: the experimental area 1 (EAR1), located at the end of the 185 m horizontal flight path from the spallation target, and the experimental area 2 (EAR2) [2], placed at 20 m from the target in the vertical direction.

The neutron beam in EAR2 is ~300 times more intense than in EAR1 in the relevant time window, since it has a ~30 times larger neutron fluence and a ~10 times shorter flight times. It was designed to carry out challenging cross-section measurements with low mass samples (<1 mg), reactions with small cross-sections or highly radioactive samples. The first (n,γ) cross section measurement at EAR2 performed with sub milligrams samples of 244,246,248Cm isotopes [4] has shown the enormous potential of the EAR2.

The high instantaneous fluence of EAR2 results in high counting rates that challenge the existing detection systems. Therefore, new devices capable of supporting very large counting rates are under development. For the case of the (n,γ) cross section measurements, a new segmented total energy detector (sTED) has been built. It consists of a physically segmented array of nine small volume C6D6 scintillators with reduced size photosensors. In comparison to standard size C6D6 detectors [5], the segmentation reduces the high counting rates and the saturation of high energy signals originated in the spallation process. In addition, the reduced size of each module allows the use of more compact readout devices (PMTs or SiPMs) with a reduced sensitivity to the background of ultra-relativistic particles coming from the spallation target.
We will present at the conference the design and construction of the sTED detector array and results of its performance in a reference capture measurement at n_TOF EAR2.

[1] Guerrero, C. et al. Eur. Phys. J. A 49, 27 (2013).
[2] C. Weiss, et al Nuc. Inst. Meth. Phy. Res. Sec. A, 799:90–98, (2015).
[3] M. Sabaté-Gilarte et al., Eur. Phys. J. A 53, 210(2017).
[4] V. Alcayne et al., EPJ Web Conf. 239 01034 (2020).
[5] R. Plag et al., Instrum. Meth. Phys. Res. A 496. 425-436 (2003).

Primary author

Victor Alcayne (CIEMAT (Spain))

Presentation Materials


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