AsianScientist (Oct. 12, 2017) – Clad in construction helmets, steel-toed boots and other safety gear, a small group of people packed on board the elevator. The simple steel structure crooned as it made its three-minute-long descent, its passengers with hands in pockets and waiting expectantly to reach their destination, almost 180 stories beneath the ground.
There, a new scientific facility was waiting to make its debut. Attending the inauguration ceremony was Dr. Sekhar Basu, Chairman of the Atomic Energy Commission (AEC) and Secretary of the Department of Atomic Energy (DAE), project leaders from the Saha Institute of Nuclear Physics (SINP) and local reporters.
Jaduguda has joined the search for dark matter.
Located in the east Indian state of Jharkhand is the Jaduguda mine complex. Presently, the country’s oldest uranium mine is no longer just a yellowcake processing facility, but a cavern for India’s top physicists to study dark matter. An old storage room in the mine was refurbished, giving the scientists a 37 square meter space buried 550 meters below the surface and enclosed by granite rock for their research. This Jaduguda facility will be home to the “mini-DINO” experiment—the first phase of Dark matter @India-based Neutrino Observatory (DINO), a proposal for an elaborate dark matter search project.
Dispelling the darkness
For centuries, mankind has looked into the black night sky and pondered what it could be made of. Astronomers like Fritz Zwicky and Vera Rubin had made careful observations of galaxies (large clusters of stars that surround black holes), finding that the total brightness and rotational speed of galaxies did not correspond with their respective measured masses. This suggested that there must exist something else in order for everything to add up, an unknown entity given the placeholder of ‘dark matter.’
Since then, calculations and derivations revealed that there exists about six times more dark matter than light matter or observable matter, such as planets and humans. However, to date, there has yet to be concrete physical evidence of dark matter.
Several hypotheses have been made about how dark matter might be detected, and what form it might exist in. There are several methods used to find dark matter, including measuring gravitational waves and analyzing high-energy neutrinos, both of which can hint at indirect signatures of dark matter. However, like other underground laboratories, the mini-DINO experiment instead aims for direct detection of dark matter particles.
One likely dark matter candidate is the weakly interacting massive particle (WIMP). In mini-DINO, scintillating calorimeters using caesium iodide (CsI) are to be set up in the Jaduguda facility to detect particle activity. CsI is a crystalline material that gets excited when struck by particles (ie. it scintillates), and is commonly used to intensify electromagnetic waves and measure energy levels of particles. As there is less cosmic background noise underground compared to the surface, the reduced interference in the underground environment allows for clearer measurements of what could represent traces of the WIMPs.
At this point, researchers cannot be completely certain that dark matter can be detected in such experiments. Even when if dark matter is detected, it is not immediately obvious what a better knowledge of dark matter can be used for. Nevertheless, these ventures will open new possibilities and enable new technologies in the long run—such curiosity-driven research has already contributed to practical inventions like electricity and wireless communication.
Opportunities for Indian science
Physics research, including dark matter research, makes tremendous contributions to modern technology and the collective knowledge of mankind. For example, this year’s Nobel Prize in Physics was awarded to three American scientists for the observation of gravitational waves at the Laser Interferometer Gravitational-Wave Observatory (LIGO), while the European Centre for Nuclear Physics (CERN) leads the world’s largest scientific collaborations.
But great science is also being done in other parts of the world—including India—away from the limelight in the West. In fact, one of the earliest detection of atmospheric neutrinos (high energy particles produced from cosmic rays interacting with the atmosphere) was made in India in 1965. The experiments were run in the Kolar Gold Fields (KGF) at the depth of 2,300 meters, much deeper than the new Jaduguda facility.
In its 25 years of operation, the KGF experiments not only logged in crucial data for neutrino theories but also captured extremely rare decays known as Kolar events, hinting at the existence of an unknown massive particle which could be related to dark matter. The data from the Kolar events was, however, insufficient to be conclusive. No further experiments could proceed at the site as it closed down—the mine was exhausted and there were insufficient funds to maintain the mine for the experiments in the absence of mining activities.
In an ideal world, the KGF experiments would still be making more valuable experimental data available for interpretation and celebrating their 53rd anniversary this year. Other projects—such as the India-based Neutrino Observatory (INO), the main project which mini-DINO is linked to—have been stalled due to regulatory issues and a lack of support. INO was designed to study neutrinos, which are common but elusive particles that are involved in interactions that can open new frontiers in physics.
But not all hope is lost. Jaduguda’s mini-DINO is a step forward, a fairly cheap (~US$30,000) investment based on existing infrastructure. The mini-DINO project could possibly be expanded, and there is intent to continue to set up INO in the future.
If and when it gets the the green light, INO will become the region’s largest pure-science research facility and stand as a unique icon representing India’s stellar research capacity. Building INO would spur on the local and global community and the next generation of scientists as a key contributor in the persistent search for knowledge.
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Copyright: Asian Scientist Magazine; Photo: Shutterstock.
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