New method for making improved radiation detectors

May 31, 2007

Scientists at the U.S. Department of Energy's Brookhaven National Laboratory, with funding from DOE's National Nuclear Security Administration, have devised ways to improve the performance of radiation detectors, such as those used by law enforcement agencies to locate and identify radioactive material.

The improved sensors, for which the Laboratory has filed a U.S. provisional patent application, can be used at room temperature, which makes them more practical and cost-effective than existing detectors with similar performance, which must be operated at very cold temperatures using expensive liquid nitrogen. They can also more accurately detect the X-rays and gamma rays emitted by radiological sources such as dirty bombs and other illicit materials.

"Improving the performance of radiation detectors could improve the efficiency and accuracy of cargo screening at U.S. ports," said Brookhaven physicist Aleksey Bolotnikov, one of the inventors.

Radiation detectors work by detecting electrons and "holes" — vacancies left by liberated electrons — when ionizing radiation or high-energy particles strike the detector crystal. When the free electrons and holes flow toward electrodes (an anode and a cathode) at either end of the detector, they generate a signal that can be measured and recorded.

In an ideal detector, all of the electrons and holes created by the ionization process would arrive at the electrodes. But in reality, holes travel a very short distance before getting trapped by defects in the crystal. Also, because the electrostatic field inside the detector causes some of the electrons to drift, not all of them arrive at the anode. These losses lead to a subsequent inaccuracy in radiation measurements.

The Brookhaven-designed sensors improve on this situation by combining methods to shield the detector and focus the electrons toward the anode. In addition, the electrodes at each end of the detector give information about how many electrons/holes get trapped. This "correction factor" can then be used to reconstruct the number of electrons/holes originally created by incident gamma rays or high-energy particles.

"Together, these techniques enhance the energy resolution and efficiency of these detectors. In practical terms it means that the improved devices will be able to detect more minute quantities of radiation, detect radioactive materials more quickly or from greater distances, better identify the source of the radiation, and distinguish illicit sources of concern from common naturally occurring radioactive materials," Bolotnikov said.

The patent application covers the improved high-energy detectors, as well as methods for making and using them. Details of the electrode design and processing methods are also included.

Source: DOE/Brookhaven National Laboratory

Explore further: This company's scanning technology is a smugglers' nightmare

Related Stories

Fields and flows fire up cosmic accelerators

May 16, 2017

Every day, with little notice, the Earth is bombarded by energetic particles that shower its inhabitants in an invisible dusting of radiation, observed only by the random detector, or astronomer, or physicist duly noting ...

Recommended for you

Musk, Zuckerberg duel over artificial intelligence

July 25, 2017

Visionary entrepreneur Elon Musk and Facebook chief Mark Zuckerberg were trading jabs on social media over artificial intelligence this week in a debate that has turned personal between the two technology luminaries.

Adobe bidding Flash farewell in 2020

July 25, 2017

Adobe on Tuesday said its Flash software that served up video and online games for decades will be killed off over the next three years.

Microsoft Paint brushed aside

July 24, 2017

Microsoft on Monday announced the end of days for its pioneering Paint application as it focuses on software for 3-D drawing.

Hyperloop or hyperbole? Musk promises NY-DC run in 29 mins

July 21, 2017

US entrepreneur Elon Musk said Thursday he'd received tentative approval from the government to build a conceptual "hyperloop" system that would blast passenger pods down vacuum-sealed tubes from New York to Washington at ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.