Author: College of Engineering

Sue Hill is the Digital Content Manager for the College of Engineering.

Hao Zhou Research

HAWC Experiment
Figure 1: The HAWC experiment as of July 26, 2013. The full array will cover the whole plane in the center of the picture.

I am working with Dr. Petra Huentemeyer on the HAWC (short for High Altitude Water Cherenkov) experiment, a very high energy (VHE) gamma-ray observatory currently being built in Mexico. In contrast to optical or radio waves, gamma-ray photons cannot penetrate the Earth’s atmosphere. Instead they collide with particles in the atmosphere and create showers of secondary particles through electromagnetic and hadronic interactions. Once completed the HAWC experiment will consist of 300 water Cherenkov detectors (WCDs), that will measure these secondary particles as they sweep through the array. The directions of the primary gamma-ray photons are reconstructed using the time between the signals in each WCD. Thus timing calibration, which is what I am currently working on, is crucial for good angular resolution. As of now, more than one third of the array is finished and operational. At the moment, I am doing a preliminary analysis of data collected with this sub-array. Figure 1 shows a picture of HAWC on July 26, 2013. My research is focusing on pulsar wind nebulae (PWNe), the largest class of galactic VHE gamma-ray sources. PWNe produce electromagnetic radiation in a very broad energy range from radio to VHE gamma rays, and thereby provide an excellent laboratory to study the physical processes at very high energy. Figure 2 shows the crab nebula at different wavelengths. Using data collected with the complete HAWC array, I will reconstruct the energy spectrum of gamma rays emitted by PWNe. I will combine my analysis results with data from other experiments that take measurements at lower energies, to reveal the physics processes occurring in PWNe.

by Hao Zhou

Crab Nebula
Figure 2: Crab nebula in radio (red), optical (green) and X-ray (blue) from APOD (Astronomy Picture of the Day) on September 20, 2002. Credit: J. Hester (ASU), CXC, HST, NRAO, NSF, NASA

SURF Presentations August 12 and 13, 2013

Recipients of Summer Undergraduate Research Fellowships (SURFs) will present end-of-summer project updates Monday and Tuesday (Aug. 12 and 13), from 9 to 11 a.m., in Fisher 139.

From Tech Today.

SURF award recipients in physics include:

Joseph Charnawskas
Advisor: Raymond Shaw
The Effects of the Gravitational Force on Water Particles in a Turbulent Flow

Mick Small
Advisor: Yoke Khin Yap
Photovoltaic Responses of Quantum Dot Sensitized ZnO Nanowires

Angela Small (Honor’s Institute)
Advisor: Jacek Borysow
Analysis of Artificial Breath Samples Using Raman Spectroscopy for Medical Diagnosis

Kevin Rocheleau (Honor’s Institute)
Advisor: Petra Huentemeyer
Analysis and Modeling of Diffuse Gamma-Ray Emission from the Cygnus Region using FERMI and HAWC Data

Jaszczak Publishes on Nanotech Innovations

Journal of Nano EducationProfessor John Jaszczak (Physics), former undergraduate student Echoe Bouta, and Professor of Practice Mary Raber (Institution for Interdisciplinary Studies) published a paper “Nanotech Innovations Enterprise at Michigan Technological University” in the latest edition of Journal of Nano Education, which is a special issue commemorating ten years of National Science Foundation funding of Nanotechnology Undergraduate Education programs.

From Tech Today.

Visit Nanotech Innovations

Fan Yang Research

Fan Yang - Nucleation Rates
Figure 1. wi and ni relationship for two ice nucleation rates. Blue points are from LES with lower ice nucleation rate and red points are higher ice nucleation rate. Solid and dashed lines are best fitted 2.5 slope lines.

Minimalist model of ice microphysics in mixed-phase stratiform clouds

Fan Yang

Advisor: Raymond Shaw

Mixed-phase clouds, which can exist days even weeks, are frequently observed in the Arctic region where they play an important role in the radiation balance. Observations also show that ice particles precipitate from these clouds nearly all time. The question of whether persistent ice crystal precipitation from supercooled layer clouds can be explained by time-dependent, stochastic ice nucleation is explored using an approximate, analytical model, and a large-eddy simulation (LES) cloud model. The updraft velocity in the cloud defines an accumulation zone, where small ice particles cannot fall out until they are large enough, which will increase the residence time of ice particles in the cloud. Ice particles reach a quasi-steady state between growth by vapor deposition and fall speed at cloud base. The analytical model predicts that ice water content (wi) has a 2.5 power law relationship with ice number concentration (ni). wi and ni from a LES cloud model with stochastic ice nucleation also confirm the 2.5 power law relationship. The prefactor of the power law is proportional to the ice nucleation rate, and therefore provides a quantitative link to observations of ice microphysical properties. Figure 1 shows LES results for two ice nucleation rates: Blue points correspond to low ice nucleation rate and red points to high ice nucleation rate. It’s clearly to see that points follow the 2.5 power law as our analytical model expected. The intercept shift predicted by the minimalist model is 1.05, which is very close to the best fitted line shift in Figure 1, 5.77-4.75=1.03. This provides a compelling link between ice microphysical properties and the ice nucleation rate within the cloud, which may be used in future analysis of cloud observation.


Yang, F., M. Ovchinnikov, R.A. Shaw (2013), Minimalist model of ice microphysics in mixed-phase stratiform clouds, Geophys. Res. Lett. doi: 10.1002/grl.50700 (accepted)

Alum Bhabana Pati Visited on Friday

Jacek Borysow and Bhabna Pati
Jacek Borysow and Bhabana Pati

Dr. Bhabana Pati visited the department on Friday, July 12, 2013. Bhabna graduated in 1997 with a Ph.D. after working with Dr. Jacek Borysow as a “laser junkie.” She developed the single mode tunable titanium sapphire laser and subsequently tunable ultraviolet laser via sum frequency generation in a non-linear crystal.

Today she is a principal scientist at Q-Peak Co. and still a “laser junkie,” trying among many other things to shoot lasers at the Moon to find out its composition via Laser Induced Breakdown Spectroscopy.

Grand Slam: Jaszczak Contributes to Four Articles in Rocks and Minerals


The March/April edition of the magazine Rocks & Minerals would be considerably slimmer if physics professor John Jaszczak’s contributions were extracted.

With John Rakovan (Miami University), he coordinated a series of articles on mining in the Arusha region of Tanzania. He coauthored “Miracle at Merelani,” an article on minerals found at the Karo Mine, providing electron microscope images and photos of many showy specimens from the Seaman Mineral Museum. He also edited a pictorial of Merelani, a village near the mine.

In addition, he coauthored “Fluorapatite from a Remarkable Occurrence of Graphite and Associated Minerals,” providing three photos for the article.

Lastly, Jaszczak wrote the Word to the Wise column entitled “Raman Spectroscopy in the Identification and Study of Minerals,” which introduced readers to this powerful tool for identifying and characterizing minerals.

From Tech Today.