COHERENT at the SNS

Detector Subsystems

Location of Detector Systems in Neutrino Alley

Active Systems

CENNS-10 Lar Detector

Single-Phase LAr Subsystem

Liquid argon (LAr) detectors continue to be instrumental in high energy physics. Efforts to reduce thresholds and inform the LAr detector response are crucial for future WIMP searches, long baseline experiments, and CEvNS measurements.

CENNS-10 is a single phase liquid argon (LAr) detector developed at Fermilab.  Two facing PMTs see a 22kg mass of LAr.  It has been operating at the SNS since December 2016 and will be upgraded to improve light collection in the summer of 2017.  The LAr working group convener is Rex Tayloe.

 

 

 

 

Rendering of the 750 kg LAr detector cryostat

The groundwork for the 610 kg fiducial mass of CENNS-750 detector is laid, to provide precision measurements of the CEvNS cross-section on argon, to probe processes such as the charged-current (CC) response of argon nuclei, and search for accelerator-produced dark matter with unprecedented sensitivity. The primary purpose of operating CENNS-750 is to demonstrate the feasibility of a future ~10 t design and mitigate the associated risks, CENNS-750 will already provide competitive preliminary limits on accelerator-produced dark matter.

 

 

 

 

 

185-kg NaI[Tl] Detector

NaI (TI) Subsystem

A 185-kg NaI[Tl] detector was deployed at the SNS in June 2016. This detector was built to study the neutrino charged-current interaction on iodine-127 and to measure beam-related backgrounds for a CEvNS search using sodium recoils. Plans are underway for a ton-scale deployment that will simultaneously measure these cross-sections. Apart from drastically different energy scales, the charged-current interaction only occurs for electron neutrinos, whereas CEvNS should occur for all flavors of neutrinos. The NaI[Tl] working group conveners are Phil Barbeau and Jason Detwiler.

 

 

 

 

 

 

Neutrino Alley(left) and MARS(right)

MARS Neutron Detector

MARS module has 16 photomultiplier tubes monitoring the signals from interwoven EJ200
scintillator and gadolinium-doped Mylar. Paired analyses are done because the neutron will leave two energy depositions in MARS – it will down-scatter and thermalize in the scintillator, then capture on the gadolinium. It has been deployed to Neutrino Alley since June of 2017, but it was moved to a new location in January 2019. The MARS working group convener is Rebecca Rapp.

 

 

 

Neutrino Cubes

Neutrino Induced Neutron Detectors

The first neutrino cube was deployed to the SNS in September 2015. It was designed to measure neutrino-induced neutrons (NINs) in lead, which are a background for CEvNS measurements. A second neutrino cube was deployed in February 2017 to search for NINs in Iron.  The neutrino cube working group convener is Phil Barbeau.

 

 

 

 

 

 

 

Planned Systems

HPGe Detector

HPGe PPC Subsystem

The HPGe detector system consists of 10 kg of p-type point-contact germanium detectors.  Germanium detectors have very good energy resolution and would be a cross-section between that for the LAr and CsI[Na] detectors.  These are being tested and should be deployed in 2017.  The HPGe working group convener is Matthew Green.

 

 

 

Rendering of 670kg Flux Normalization Detector by Eric Day, CMU

D2O Subsystem

To benchmark the neutrino flux, a 1300-kg D2O detector is planned to construct in two modules. Each module will consist of an upright cylinder, with D2O contained inside a central acrylic cylinder, contained inside a steel tank with 10 cm of H2O tail catcher. Twelve PMTs view the volume from above.

 

 

 

 

 

 

Past System

CsI[Na] Detector being assembled at the SNS

CsI (Na) Subsystem

The CsI[Na] detector is the world’s smallest working neutrino detector at 14.6kg and has been operational at the SNS since July 2015.  The CsI[Na] crystal is shielded with low background materials and has been instrumented with a super-bialkali photo-multiplier tube.  The CsI[Na] working group convener is Juan Collar.