2012 Fiscal Year Annual Research Report
超新星爆発によるニュートリノ信号と重力波信号の相関の研究
| Project Area | New development in astrophysics through multimessenger observations of gravitational wave sources |
|---|
| Project/Area Number |
24103004
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
ヴァギンズ マーク 東京大学, カブリ数物連携宇宙研究機構, 教授 (90509902)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
小汐 由介 岡山大学, 自然科学研究科, 准教授 (80292960)
|
|---|
| Project Period (FY) |
2012-06-28 – 2017-03-31
|
| Keywords | 重力波 / 超新星爆発 / ニュートリノ / ガドリニウム |
|---|
| Research Abstract |
The EGADS (Evaluating Gadolinium's Action on Detector Systems) laboratory is located one kilometer underground in the Mozumi mine in northern Gifu-ken, close to 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 is to convert EGADS into the world's most advanced supernova neutrino detector.
In order to realize this new phase of EGADS (which now stands for Employing Gadolinium to Autonomously Detect Supernovas) the single most important task involves a complete upgrade of the front-end electronics (currently based on 20-year-old ATM boards). To accomplish this upgrade -which will provide the deadtime- less and zero-energy-threshold functionality needed to literally collect every possible bit of information during a once-in-a-lifetime galactic supernova explosion - new readout boards for all 240 photomultiplier tubes in EGADS must be produced.
This year these new, custom electronics modules (known as QBEE's) were commissioned and completed, along with a couple of spares.
In addition to this, EGADS's all-important selective water filtration system, which keeps the water in the detector clean but does not remove the dissolved gadolinium, has been upgraded via the installation of a fast recirculation subsystem. This new loop keeps the water even cleaner than before, but still allows the desired Gd levels to be indefinitely maintained.
|
| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Although basically I feel that (2) is the most representative answer for where the project stands - we are making excellent, steady progress toward our supernova detection goals - I still must say (3) is the most technically correct answer.
This is primarily because the production and delivery of the QBEE's from the vendor (Iwatsu) was several months slower than expected. As a result, we are a bit behind the pace outlined in the original proposal. However, while waiting for the new electronics we have already achieved full galaxy supernova neutrino sensitivity using the old ATM electrons, and are currently online and taking data 24 hours a day, though at a somewhat reduced detection efficiency. This will be remedied after the QBEE's are installed later this year.
|
| Strategy for Future Research Activity |
The QBEE's will be installed sometime later this year, at which point we will be the most advanced supernova neutrino detector in the world.
We will then install a specialized realtime computer which will receive and analyze every byte of data (include all PMT dark noise and radioactively induced backgrounds) as it is collected. It will filter 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.
The ultimate goal of this upgraded EGADS detector is to have the capability to alert the other members of this multimessenger Kakenhi that a supernova explosion is taking place in our galaxy within one second of the first neutrino's arrival in EGADS.
A prompt alert provided by EGADS will help KAGRA look for a signal in their data; both gravitation radiation and neutrinos would be emitted at the same moment from an asymmetric explosion. Concerning the other messengers - visible light, infrared radiation, X-rays, and gamma rays - the knowledge gained in the precious few hours between the arrival of the neutrinos (which are generated first) and the arrival of the supernova's first light (the so-called shock breakout) will serve to guide and optimize the subsequent multi-wavelength observations of the dying star.
Therefore, in addition to keeping EGADS in good working order with the highest possible uptime fraction, continued co-ordination with the other Kakenhi members is essential, and will be vigorously pursued.
|
-
-
-
-
-
-
-
[Presentation] GADZOOKS!2013
Author(s)
Yusuke Koshio
Organizer
13th International Conference on Topics in Astroparticle and Underground Physics (TAUP2013)
Place of Presentation
Asilomar, California, USA
Year and Date
20130908-20130913
Invited
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
