{"683457":{"#nid":"683457","#data":{"type":"event","title":"MS Proposal by Federico Preve","body":[{"value":"\u003Cp\u003E\u003Cstrong\u003EFederico Preve\u003C\/strong\u003E\u003Cbr\u003E\u003Cem\u003E(Advisor: Prof. Steinberg]\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003Ewill propose a master\u2019s thesis entitled,\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ELow noise double-beam laser absorption\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003Espectroscopy for ammonia sensing\u003C\/strong\u003E\u003Cem\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EOn\u003C\/em\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EThursday, August 14 at 9 a.m.\u0026nbsp;\u003C\/strong\u003E\u003Cbr\u003E\u003Cstrong\u003EBen T. Zinn Combustion Laboratory 107\u003C\/strong\u003E\u003Cbr\u003E\u003Cbr\u003E\u0026nbsp;\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EAbstract\u003C\/strong\u003E\u003Cbr\u003EThis research focuses on adapting an active noise-cancellation circuit for double-beam laser absorption spectroscopy to improve ammonia concentration measurements. By suppressing common-mode laser intensity noise, the circuit enhances absorption sensitivity without requiring complex modulation techniques. A tunable diode laser beam is split into two paths: a signal beam that passes through an absorption cell and a reference beam that bypasses any absorbing medium. The two laser beams are independently detected, and their corresponding photocurrents are fed into an electronic circuit designed to suppress the common-mode noise on laser intensity, thereby enhancing the diagnostic technique\u2019s accuracy. This architecture remains cost-effective and has the potential to achieve shot-noise-limited performance.\u003C\/p\u003E\u003Cp\u003EA circuit originally designed by Philip Hobbs was adapted, simulated in Analog Devices LTspice, and prototyped on a breadboard. The circuit was tested using a water vapor absorption setup and benchmarked against both a DAS sensor and a commercial double-beam noise cancellation module from MKS-Newport. Results showed a clear improvement in NEA over standard DAS, with performance approaching that of the commercial system. Optimal beam-splitting ratio and frequency response (\u0026gt;10 kHz) were characterized.\u003C\/p\u003E\u003Cp\u003EThe next phase of the project will focus on adapting the circuit for ammonia diagnostics using extended InGaAs photodetectors, which operate at the near-infrared wavelengths relevant to ammonia absorption. The circuit will then be transferred to a printed circuit board and housed in a Faraday cage to minimize electronic noise and improve system performance. Two experimental demonstrations are planned to validate the sensor\u2019s performance. The first is a compression-driven test in a gas cell, initially at low pressure, to track transient ammonia absorbance while collisional broadening increases as the cell fills with ambient air. The second is a shock tube experiment, where time-resolved measurements of ammonia absorption will be used to determine its pyrolysis rate across a range of temperatures and pressures.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECommittee\u003C\/strong\u003E\u003C\/p\u003E\u003Cul\u003E\u003Cli\u003EProf. Adam Steinberg \u2013 School of Aerospace Engineering (advisor)\u003C\/li\u003E\u003Cli\u003EProf. Wenting Sun\u2013 School of Aerospace Engineering (advisor)\u003C\/li\u003E\u003Cli\u003EDr. Shawn Wehe \u2013 Principal Research Engineer, School of Aerospace Engineering\u003C\/li\u003E\u003C\/ul\u003E\u003Cp\u003E\u0026nbsp;\u003C\/p\u003E","summary":"","format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003E\u003Cstrong\u003ELow noise double-beam laser absorption\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003Espectroscopy for ammonia sensing\u003C\/strong\u003E\u003Cem\u003E\u003Cstrong\u003E\u0026nbsp;\u003C\/strong\u003E\u003C\/em\u003E\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Low noise double-beam laser absorption spectroscopy for ammonia sensing "}],"uid":"27707","created_gmt":"2025-08-01 11:52:09","changed_gmt":"2025-08-01 11:52:41","author":"Tatianna Richardson","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2025-08-17T09:00:00-04:00","event_time_end":"2025-08-17T11:00:00-04:00","event_time_end_last":"2025-08-17T11:00:00-04:00","gmt_time_start":"2025-08-17 13:00:00","gmt_time_end":"2025-08-17 15:00:00","gmt_time_end_last":"2025-08-17 15:00:00","rrule":null,"timezone":"America\/New_York"},"location":"Ben T. Zinn Combustion Laboratory 107","extras":[],"groups":[{"id":"221981","name":"Graduate Studies"}],"categories":[],"keywords":[{"id":"166866","name":"MS Proposal"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1788","name":"Other\/Miscellaneous"}],"invited_audience":[{"id":"78771","name":"Public"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[],"email":[],"slides":[],"orientation":[],"userdata":""}}}