NASA’s new detectors could improve views of gamma-ray events

Utilizing expertise much like that present in smartphone cameras, NASA scientists are creating upgraded sensors to disclose extra particulars about black hole outbursts and exploding stars—all whereas being much less energy hungry and simpler to mass produce than detectors used at this time.

“When you consider black holes actively shredding stars, or neutron stars exploding and creating actually high-energy bursts of sunshine, you’re looking on the most excessive occasions within the universe,” stated analysis astrophysicist Dr. Regina Caputo. “To watch these occasions, it’s good to take a look at the highest-energy type of mild: gamma rays.”

Caputo leads an instrument-development effort referred to as AstroPix at NASA’s Goddard House Flight Heart in Greenbelt, Maryland. The silicon pixel sensors in AstroPix—nonetheless in growth and testing—are paying homage to the semiconductor sensors that enable smartphone cameras to be so small.

“Gamma rays are notoriously difficult to measure due to the way in which that the incoming particle interacts along with your detector,” stated Dr. Amanda Steinhebel, a NASA Postdoctoral Program fellow working with Caputo.

Gamma rays are wavelengths of sunshine extra energetic than ultraviolet and X rays, and their photons act extra like particles than waves. “As an alternative of simply being absorbed by a sensor like visible light,” Steinhebel stated, “gamma rays bounce throughout.”

NASA’s Fermi Gamma-ray House Telescope, which has studied the gamma-ray sky since 2008, solved the “bounce” downside in its major instrument through the use of towers of strip-shaped sensors. This table-sized dice, Fermi’s Giant Space Telescope, was itself groundbreaking expertise when the mission launched.

Every strip maps a gamma-ray strike in a single-dimension, whereas layers of strips oriented perpendicular to one another document the second dimension. Gamma rays generate a cascade of energetic strikes by means of a number of layers, offering a map pointing again to the supply.

In regards to the measurement of a golf bag, a space telescope instrument utilizing AstroPix sensors would require half as many layers because the Fermi strip detector expertise, Caputo stated.

“It is simpler to inform precisely the place particles work together,” Steinhebel stated, “since you simply determine the purpose within the grid that it interacted with. Then you definately use a number of layers to actually hint again the paths that particles took by means of it.”

AstroPix may document lower-energy gamma rays than present expertise, Steinhebel defined, as a result of these photons are inclined to get misplaced filtering by means of the a number of layers of a strip detector. Capturing them would supply extra details about what occurs throughout short-lived, energetic occasions. “These low-energy gamma rays are most typical throughout peak burst brightness,” she defined.

The pixel detectors additionally eat much less electrical energy to function, Caputo stated, a serious upside for future missions planning out their energy utilization.

Pixelated silicon detectors have been confirmed in particle accelerator experiments, she stated, and their frequent use and mass production for cell telephones and digital cameras make them simpler and cheaper to acquire.

Creating completely different prototypes over a number of years and seeing AstroPix create correct plots of gamma-ray mild has been exhilarating and very satisfying, Steinhebel stated.

Whereas the group continues to work on creating and enhancing their expertise, Caputo stated the following step can be to launch the expertise on a brief sounding rocket flight for additional testing above Earth’s ambiance.

They hope to learn a future gamma-ray mission meant to additional the examine of high-energy universe occasions.

“We are able to do such cool science with this,” Caputo stated. “I simply need to see that occur.”