Zhong He | Faculty
When Michigan Nuclear Engineering and Radiological Sciences professor Zhong He and his company, H3D, started selling the Polaris-H radiation detector in 2013, many hailed it as a game-changer for nuclear safety.
Game-changing, maybe. But He is quick to point out this didn’t happen overnight. The technology is actually older than some undergraduates.
He and generations of graduate students in his Orion Radiation Measurement Group - some of whom now work for H3D - have spent 18 years developing the world’s first portable, practical gamma ray camera. The toaster-size handheld device not only detects radiation but shows exactly where it’s located and identifies the radioactive material that’s spewing it.
Originally developed for the U.S Department of Defense in order to detect nuclear weapons, He’s technology now helps doctors track the precise path of radiation therapy and is being built into NASA rovers. In nuclear power plants around the world, it detects radiation and fuel leaks, which can be both dangerous and costly.
Gamma ray detectors typically fall into two groups: scintillation detectors, which are portable but can’t show where radiation is coming from, and germanium detectors, which provide much more information but are big and heavy, with components that must first be cooled to minus-200 degrees Celsius. He’s gamma camera provides as much information as the germanium detectors and works at room temperature.
“What people really love is the imaging capability,” He said. “You can see where the source is.”
Without the ability to pinpoint the radiation source, he said, nuclear power plants have sometimes put protective shielding around a suspected radiation source, only to find later that the radiation was coming from somewhere else.
“Hopefully, we can provide a tool so people can generate nuclear power more safely, and hopefully, we can see someday that we’ve prevented some accidents from happening,” He said.
He studied nuclear physics as an undergraduate in China - a natural path for a young man who’d always been curious about the universe and the way things work. That led to graduate work with gamma ray telescopes as part of China’s High Energy Physics Institute. Unlike optical telescopes which can only reveal the surface physics of a star, gamma ray scopes reveal how the stars were formed and, by extension, answer questions about the evolution of the universe.
Gamma rays fascinated He. Unlike the photons that make up visible light, gamma rays can’t be contained. They behave more like bullets than waves, passing through anything in their path. They’re challenging to work with, but the information they reveal about a material’s nuclear workings make it worth the trouble.
Michigan’s reputation in radiation detection research - along with its proximity to Ontario, Canada, where He’s wife was working on her PhD - would eventually draw him to Ann Arbor, where his fascination with gamma rays has continued to shape his career.
He began working on the Polaris technology in 1997, gaining momentum as advances in materials and electronics gradually brought performance up and production prices down. He launched H3D in 2011 and started selling detectors commercially in 2013.
The company is now working to evolve the original system into a modular one called Orion - the constellation to Polaris’s lone star - that would detect and identify radiation over large areas. Orion’s electronics are more sophisticated and compact than Polaris’s, with components that can be configured to changes in scale.
“With Orion you can build bigger and bigger systems, and also you can make arrays of systems,” He said. “If, say, the military was using it, everybody can have a small sensor, and then they form a human network.”
Southampton University, U.K.
PhD Physics ’93
High Energy Physics Institute, Academia Sinica, China
MS Physics ’89
Tsinghua University, Beijing, P.R. China
BS Physics ’86
Position-sensitive room-temperature semiconductor radiation imaging detectors, low-noise charge sensitive application specific integrated circuitries, gamma-ray image reconstruction, gas and scintillation radiation detectors, PET nuclear medicine imaging, experimental gamma-ray astrophysics.
Honors and Awards
- 2013 College of Engineering Rexford E. Hall Innovation Excellence Award, UM
- 2012 Room-Temperature Semiconductor Detector Scientist Award
- 2010 Top 100 R&D Award (PNNL & UM)
- Outstanding Faculty Achievement Award, Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2005
- Outstanding Teaching Award (voted by students), Department of Nuclear Engineering and Radiological Sciences, University of Michigan, in 1999 and 2003.
- 2008 - Present: Professor, Nuclear Engineering & Radiological Sciences (NERS), UM.
- 2004-2008: Associate Professor, Nuclear Engineering & Radiological Sciences Dept.
- 1998-2004: Assistant Professor, Nuclear Engineering & Radiological Sciences Dept.
- 1995-1998: Assistant Research Scientist, Nuclear Engineering & Radiological Sciences Dept.
- 1994-1995: Post-doctoral research fellow, NERS, UM.
OTHER PROFESSIONAL ACTIVITIES
- Reviewer of Nuclear Instruments and Methods in Physics Research A, since 1994.
- Reviewer of IEEE Transactions on Nuclear Sciences, since 1993.
- Reviewer of Journal of Applied Physics and Applied Physics Letters, since 2002.
- Proposal reviewer for U.S. Civilian Research and Development Foundation, DOE, NSF, NASA.
- Member of the Program Committee: SPIE International Symposium on Optical Science, Engineering, and Instrumentation, program on Hard X-Ray and Gamma-Ray Detector Physics, Optics, and Applications, since 1997.
- NASA High Energy Astrophysics (SR&T program) Peer Review Panel, 2002 – 2005, 2007
- Program chair of SORMA international conference, May 2006, May 2010 & June 2014, Ann Arbor, Michigan (general chair was Professor David Wehe)
Ten Selected Publications
(Selected from 93 peer-reviewed publications)
- Z. He, G.F. Knoll, D.K. Wehe, R. Rojeski, C.H. Mastrangelo “1-D Position Sensitive Single Carrier Semiconductor Detectors.” Nuclear Instruments and Methods in Physics Research A380 (1996) 228-231.
- Z. He, G.F. Knoll, D.K. Wehe, J. Miyamoto “Position Sensitive Single Carrier CdZnTe Detectors.” Nuclear Instruments and Methods in Physics Research A388 (1997) 180-185.
- Z. He, W. Li, G.F. Knoll, D.K. Wehe, J. Berry, C.M. Stahle “3-D Position Sensitive CdZnTe Gamma- Ray Spectrometers.” Nuclear Instruments and Methods in Physics Research A422 (1999) 173-178.
- Zhong He “Review of the Shockley-Ramo Theorem and Its Applications in Semiconductor Gamma-Ray Detectors.” Nuclear Instruments and Methods, A463 (2001)250-267.
- Zhong He and Ronald D. Vigil “Investigation of pixellated HgI2 gamma-ray spectrometers.” Nuclear Instruments and Methods in Physics Research A492 (3) (2002) 387-401.
- Feng Zhang, Zhong He, Dan Xu, Glenn F. Knoll, David K. Wehe, James E. Berry “Improved Resolution for 3D Position Sensitive CdZnTe Spectrometers.” IEEE Transactions on Nuclear Science, Vol.51 (5) (2004) 2427 – 2431.
- D. Xu, Z. He, “Gamma-ray energy-imaging integrated spectral deconvolution”, Nuclear Instruments and Methods in Physics Research A 574 (2007) 98-109.
- S.D. Kiff, Z. He, G. Tepper “Improving Spectroscopic Performance of a Coplanar-Anode High- Pressure Xenon Gamma-Ray Spectrometer,” IEEE Transactions on Nuclear Science, Vol. 54, No.4 (2007) 1263 – 1270.
- Christopher G. Wahl and Zhong He “Gamma-Ray Point-Source Detection in Unknown Background Using 3D-Position-Sensitive Semiconductor Detectors,” IEEE Transactions on Nuclear Science, vol.58, no.3, pp.605-613, June 2011.
- Yuefeng Zhu, Steve E. Anderson, Zhong He “Sub-Pixel Position Sensing for Pixelated, 3-D Position Sensitive, Wide Band-Gap, Semiconductor, Gamma-Ray Detectors,” IEEE Transactions on Nuclear Science , vol.58, no.3, pp.1400-1409, June 2011.