Rishi (Metea Valley High School) and Sartaj (Naperville Central High School)

In 2008, the DAMA-LIBRA collaboration (D-L) released reports claiming the detection of Weakly Interacting Massive Particles (WIMPs), essentially reporting direct detection of dark matter. D-L used sodium iodide scintillators coupled to photomultiplier tubes to measure signals of WIMP particles passing through. An annual modulation in the signal, close to 6 KeV, was found. It corresponded to the expected seasonal change in dark matter interactions, which are expected to occur from the Earth's motion through the galactic dark matter halo. Since then, no other experiment has produced the same results.

One theory that tries to explain the results of the D-L experiment says that the energy difference was due to a time delay in the NaI scintillator. As particles pass through NaI, the crystal would release most of the energy gained from the particles as light. However, a small but substantial amount of energy would be left within the scintillators, and would be released at a later time. The theory postulates that this delay in response was the signal noticed by D-L.

Rishi and Sartaj worked together with Lauren Hsu to find out if this proposed time delay caused the DAMA-LIBRE results. They didnít find the time delay, but Rishi and Sartaj were able to learn many useful skills such as how to calibrate a PMT and many things about other types of electronics. You can find a link to their presentation below. (In pdf form)

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