ICARUS at the Fermilab Short-Baseline Neutrino program: initial operation

Abstract

The ICARUS collaboration employed the 760-ton T600 detector in a successful 3-year physics run at the underground LNGS laboratory, performing a sensitive search for LSND-like anomalous ${\nu }_e$ appearance in the CERN Neutrino to Gran Sasso beam, which contributed to the constraints on the allowed neutrino oscillation parameters to a narrow region around 1 eV${}^2$. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 the cryogenic commissioning began with detector cool down, liquid argon filling and recirculation. ICARUS then started its operations collecting the first neutrino events from the booster neutrino beam (BNB) and the Neutrinos at the Main Injector (NuMI) beam off-axis, which were used to test the ICARUS event selection, reconstruction and analysis algorithms. ICARUS successfully completed its commissioning phase in June 2022. The first goal of the ICARUS data taking will be a study to either confirm or refute the claim by Neutrino-4 short-baseline reactor experiment. ICARUS will also perform measurement of neutrino cross sections with the NuMI beam and several Beyond Standard Model searches. After the first year of operations, ICARUS will search for evidence of sterile neutrinos jointly with the Short-Baseline Near Detector, within the Short-Baseline Neutrino program. In this paper, the main activities carried out during the overhauling and installation phases are highlighted. Preliminary technical results from the ICARUS commissioning data with the BNB and NuMI beams are presented both in terms of performance of all ICARUS subsystems and of capability to select and reconstruct neutrino events.

Fig. 1

Left: internal view of one ICARUS-T600 module evidencing the main components of its two TPCs. Right: schematic view of the ICARUS-T600 readout principle, shown for one TPC

Fig. 2

One of the two new ICARUS cryostats during its assembly at a CERN workshop

Fig. 3

A2795 custom board housing 64 amplifiers (far end), AD converter, digital control, and optical link (top-left). An assembled feed-through with nine DBBs and the biasing cables (top-right). A mini-crate populated by the nine A2795 boards installed on a feed-through flange (bottom)

Fig. 4

The new ICARUS PMTs mounted behind the wires of one TPC

Fig. 5

Picture of a vertical TOP CRT module installed in the detector hall

Fig. 6

Deployment of the ICARUS cryostats inside the pit of the SBN Far Detector experimental hall at Fermilab in August 2018 (left). Installation of TPC, PMT and laser feed-through flanges in December 2018 (center). Status of the ICARUS detector at the beginning of data taking for commissioning (right)

Fig. 7

ICARUS cryogenic plant physical layout

Fig. 8

Two low voltage power supply (LVPS) modules powering the two adjacent mini-crates populated with nine A2795 boards, serving 576 wires each

Fig. 9

Left: picture of the Side CRT. Right: top CRT horizontal modules whose installation was completed in December 2021

Fig. 10

Sketch of the CRT modules (top, side, bottom) surrounding the ICARUS-T600 detector. The Top CRT extends beyond the longitudinal size of ICARUS and includes vertical rimes complementing the Side CRT, thus allowing for full top and side coverage

Fig. 11

Trend of the liquid argon level inside the two ICARUS cryostats during the filling phase

Fig. 12

Trend of the drift electron lifetime in the two ICARUS cryostats during the commissioning phase. The sharp decreases of the lifetime are due to programmed interventions on the LAr recirculation pumps or on the cryogenic system. The lifetime quickly recovers after the end of the interventions

Fig. 13

TPC noise levels at ICARUS before and after filtering of coherent noise, as measured by waveform RMS in ADC counts (with ENC of roughly $550{\text{e}}^{-}/\text{ADC}$ [28]). Results are shown separately for the Induction 1 plane (left), Induction 2 plane (center), and Collection plane (right). Mean values of the shown distributions are presented at the bottom of each figure

Fig. 14

Fast Fourier transforms (FFTs) of noise waveform data collected by the ICARUS TPCs, before and after filtering of coherent noise. Results are shown separately for the Induction 1 plane (top), Induction 2 plane (middle), and Collection plane (bottom)

Fig. 15

Peak signal-to-noise ratio (PSNR) of ionization signals for each of the three TPC wire planes using cosmic muons in ICARUS data. Coherent noise is removed from the TPC waveforms prior to identification and measurement of the ionization signal amplitude. See the text for details on the cosmic muon data selection

Fig. 16

Results of the ionization drift velocity measurement using ICARUS cosmic muon data. Shown are Crystal Ball fits to the maximum ionization drift time distributions associated with anode-cathode-crossing cosmic muons in the two TPCs in the West cryostat

Fig. 17

Measured spatial offsets in the drift direction as a function of ionization drift distance for the two TPCs in the West cryostat, evaluated using anode-cathode-crossing cosmic muon tracks in ICARUS data. The results are compared with predictions of spatial distortions from a calculation of space charge effects (SCE) presently used in ICARUS Monte Carlo simulations (to be updated with data-driven SCE measurement)

Fig. 18

Calibrated collection plane dE/dx as a function of residual range for a selection of stopping muons in ICARUS cosmic muon data, including a comparison to the most-probable value (MPV) of dE/dx from stopping muons predicted from theory [36] (left); comparison of cosmic muon kinetic energy reconstruction by calorimetry, $E_{\text{calo}}$, and by range, $E_{\text{range}}$, showing little bias between the two methods for stopping muons in ICARUS cosmic muon data after the energy scale calibration is applied (right)

Fig. 19

PMT signal as recorded by the light detection system electronics

Fig. 20

Example of single photo-electron charge distribution collected during the PMT gain equalization campaign (PMT 93, run 7210)

Fig. 21

Gain distribution for 354 PMTs after the fine tuning equalization. The automatic procedure was not applied on 6 PMTs (not present in the plot) that were manually calibrated

Fig. 22

Side CRT cosmic event rates as a function of time. The black points corresponds to the rates from the north side CRT wall, the pink and blue points corresponds to east and west north walls, and the remaining walls are at 1 kHz rate

Fig. 23

Cosmic ray rates as a function of time for a set of Top CRT horizontal (left) and vertical (right) modules. Numbers in the legend indicate the module’s Front End Board and the black dot lines indicate the beginning and the end of 3 m overburden installation over the displayed modules: the rates reduced from 610 (260) Hz before to 330 (180) Hz after the installation of the overburden for the horizontal (vertical) modules

Fig. 24

Layout of the trigger system. SPEXI board: synchronizes the whole ICARUS detector, generates clocks and readout signals, handles beam extraction messages; 7820 FPGA boards: generate a Global Trigger in coincidence with beam extraction (Early Warning) on the basis of selected PMT signal majorities to recognize an event interaction in the LAr, to start the PMT activity recording; RT Controller implements all the features for communication with DAQ

Fig. 25

Time distribution of the recorded PMT light flashes ($\ge$ 5 fired PMT pairs in the left and right TPCs within 150 ns): the beam event excess is observed for BNB (left) and NuMI beam (right). The $1.6\mathrm{\mu }\text{s}$ and $9.6\mathrm{\mu }\text{s}$ spills duration of the beams are well recognized

Fig. 26

Cumulative sum of POT delivered by the accelerator and collected by the detector, and the daily beam utilization coefficient as a function of the operation time for BNB (NuMI) on the left (right). The dotted black line marks the separation between the two operation periods of the detector: the full month of June 2021 (Run 0) and between November 5, 2021 and June 1, 2022 (Run 1). The long break between the two periods is hidden in the plot

Fig. 27

Hit efficiency as a function of wire (pitch): blue, red and green points correspond to Induction 1, Induction 2 and Collection wires respectively. Measurement made by means of a sample of cosmic muon tracks crossing the cathode

Fig. 28

The PMTs associated with a cosmic ray muon crossing the cathode

Fig. 29

Left: distribution of $\mathrm{\Delta }z=z_{\mathit{TPC}}-z_{\mathit{PMT}}$ for a sample of cosmic ray muons crossing the cathode. Right: distribution of $\mathrm{\Delta }z=z_{\mathit{TPC}}-z_{\mathit{PMT}}$ for a sample BNB $\nu$ interactions identified by visual scanning

Fig. 30

Time difference between matched CRT hits and PMT flashes. The plot refers to Top CRT data in time with the BNB spill

Fig. 31

CRT hit time relative to the neutrino gate start time in the south wall (side CRT) for the BNB beam

Fig. 32

A visually selected ${\nu }_{\mu }$CC candidate from the BNB beam

Fig. 33

Distribution of the measured dE/dx of the muon candidate in the event shown in Fig. 32. dE/dx is reconstructed on each wire applying a preliminary calibration constant

Fig. 34

A visually selected ${\nu }_e$CC candidate from the NuMI beam

Fig. 35

Difference $\mathrm{\Delta }Z$ between the automatic and manual measured longitudinal (beam) coordinate of the neutrino interaction vertex for a sample of 476 ${\nu }_{\mu }$CC candidates from the BNB beam