| 研究実績の概要 |
The EGADS (Evaluating Gadolinium's Action on Detector Systems) laboratory is located one km underground in the Mozumi mine in northern Gifu-ken, near the Super-Kamiokande neutrino detector. Originally designed as an R&D test bed for studying the effects of dissolving gadolinium (Gd) salts in a water Cherenkov detector (Gd makes neutrons visible, which has many potential physics benefits), the purpose of this Kakenhi was to convert EGADS into the world's most advanced supernova neutrino detector.
This ambitious goal has been achieved in FY2016.
Since April 2015, the 200-ton EGADS detector has been full of water enriched with 0.2% gadolinium sulfate by mass. Once the detector itself was operating at peak efficiency, it was time to make sure the DAQ and data pipeline were equally capable. During FY2016 we performed a complete upgrade of the front-end electronics. To accomplish this, new, deadtime-less, zero-energy-threshold readout boards (known as QBEE's) for all 240 photomultiplier tubes in EGADS have been installed this year.
We then added a custom-made 56-core realtime computer to receive and analyze every byte of data (include all PMT dark noise and radioactively induced backgrounds) as it is collected. It filters the data in real time, and will be capable of immediately identifying a supernova signal as genuine thanks to the dissolved gadolinium, which acts like an amplifier for these signals.
By the end of FY2016 we unquestionably had the most advanced supernova neutrino detector in the world; EGADS now stands for Employing Gadolinium to Autonomously Detect Supernovas.
|
