Development of IR Laser Induced Breakdown Spectroscopy employing a Mercury Cadmium Telluride Array Detector
Abstract
The National Defense Authorization Act for Fiscal Year (FY) 2014 and the Department of Defense (DoD) Appropriations Act for 2014 allocated $10.7M to assist Historically Black Colleges and Universities and Minority-Serving Institutions (HBCU/MI) and to enhance their research and education capabilities in scientific areas relevant to the defense mission. The FY 2014 program supports the acquisition of research equipment and instrumentation to augment existing capabilities and to develop new capabilities that will facilitate greater participation in DoD research programs and encourage more students to pursue careers in science, technology, engineering. and mathematics (STEM) disciplines. This proposal from Principal Investigator, Dr. Uwe Hommerich, requests support for the acquisition of an eye-safe laser source, a linear mercury cadmium telluride (MCT) array detector-spectrometer system, and a digital oscilloscope to be used in time-resolved infrared laser- induced breakdown spectroscopy (IR-LIBS). LIBS has shown great promise for sensing of chemical, biological, and energetic (CBE) hazardous materials of relevance to DOD and Homeland security applications. Conventional LIBS is typically limited to atomic type transitions in the UV-VIS-NIR region (-0.2-1 µm). It is well known, however. that molecules exhibit spectroscopic signatures in the long-wavelength IR region. In an effort to augment the atomic emission spectra of conventional LIBS and to provide an increase in selectivity, researchers from HU, along with collaborators at Brimrose Corporation and Edgewood Chemical Biological Center (ECBC), demonstrated the first IR LIBS emission signatures in the 3-5 µm spectral region from several so lid-state materials. More recently, our work on IR LIBS was extended to the 5-12 µm IR region and molec ular fingerprints of several energetic materi als (e.g. ammonium nitrate, potassium chlorate) were identified using a standard 1.06 µm Nd: Y AG pump laser and single element MCT detection system. In this project, the development of an eye-safe IR LIBS system employing a multi-element MCT array is being proposed for CBE sensing applications. The system will include an eye-safe laser system operating at l.5 µm , a MCT array detector with 128 elements covering a spectral region from 2 to 12 µm. and a four channel digital oscilloscope. The new IR LIBS setup will be developed and tested at HU for sensing applications of energetic materi als (e .g. ammonium compounds, chlorate salts), and nerve agent simulants (e.g. DMMP, DIMP). For comparison, time-resolved IR LIBS studies employing a single element MCT detector and scanning spectrometer will also be performed. Experimental parameters to be varied include laser pulse energy, pump laser wavelength (1064nm versus 1540nm), pump geometry, acquisition gate delay and width. and ambient gas effects. Besides its impact on research, the proposed research will be incorporated in the research training of undergraduate and graduate students seeking degrees in STEM disciplines (physics, chemistry, computer science, and engineering). Specific educational efforts enabled through the proposed instrumentation include (1) research training of undergraduate and graduate students, (2) curriculum development in laser and optical spectroscopy techniques, and (3) outreach to local K-12 schools.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1510050
Entities
People
- Uwe Hömmerich
Organizations
- Army Contracting Command
- Hampton University
- Office of the Secretary of Defense