SBIR Award Phase I to Picometrix-NASA Differential Terahertz Imaging Methods for Enhanced Detection of Subsurface Features, Flaws, and Damage

Name: David Zimdars
Title: Mgr. of THz Development
Phone: (734) 864-5639
Email: dzimdars@picometrix.com


https://www.sbir.gov/sbirsearch/detail/1217323

Picometrix proposes to demonstrate the feasibility of using differential time domain terahertz imaging methods to enhance the contrast and detectability of features such as kissing disbonds and cracks that in conventional THz imaging only weakly reflect or scatter the THz pulses. The goal of the project is to develop methods of shearographic loading of the samples, and use the penetrating THz pulses to detect the subsurface deformation of the defects in the differential THz images with better contrast than traditional THz imaging. In a "kissing" disbond there is a region where the two sides of the material are not adhered, but the space between the two sides are essentially in perfect optical contact. When the space between the two interfaces is so optically "thin," the reflections of the THz pulses from the top and bottom surfaces cancel each other out. The defect signature is only weakly detectable compared to when the spacing is greater than the minimum THz wavelength (approx. 50-150 microns), the shearographic loading will microscopically deform defects, changing the small THz reflections in the loaded vs. unloaded state. The differential images should subtract all background clutter and highlight the microscopic subsurface distortion of the defects under loading.

API at IRMMW-2014

My Note: It's my understanding that API had two exhibition tables (pictured above), at the recent IRMMW-2014, and that both Irl Duling, Director of Terahertz Business Development Advanced Photonix, Inc., and David Zimdars, attended. 

Some highlights for API in relation to other products on display were:
The robustness of API's equipment and suitability for industrial deployment (UL, CE, 0-50degreeC temperature stability).
The reality of API's current industrial deployments across multiple applications.
API's high signal to noise ratio (40-50dB for a single waveform and 90dB for a 30sec average).
API's high speed data acquisition (up to 1000 waveforms/sec) which allows high speed imaging.
The length of API's waveform in high speed acquisition, which allows high resolution spectroscopy or examination of thick objects.
API's  volume manufacturing which results in a high value product.
The intelligence of API's Terahertz Control Unit (TCU) and its ability to do waveform processing.

2012 presents much promise and much hype in the development of Terahertz

2012 has come to a close. The year has been nothing less than "dizzying" in the continuing  development of Terahertz. Dizzying has been defined as: Make (someone) feel unsteady, confused, or amazed: "the dizzying rate of change"; "her nearness dizzied him". Because I have no technical background or training, my interest in Terahertz is that of a lay person. This makes posting any commentary authored by me,  pretentious, and perhaps naive. I acknowledge this simple truth once again, and caution readers that what I have to say about developments in this very technical field, is just that of a layman. I do note that I constantly try to find knowledgeable engineers and scientists who will share their insights with me. If any of you, want to correct any statement, false assumption or conclusion, that I make please feel free to do so.

One of the most important blog posts this year was the reprint of Carter Armstrong's article, "The Truth about Terahertz", http://terahertztechnology.blogspot.com/p/the-truth-about-terahertz.html, which describes the many challenges which remain  inherent in the effective use of Terahertz, primarily because of atmospheric attenuation, as well as the inherent limitations of THz in penetrating some materials at all. Dr. Peter Jepsen, had this to say about the article:
"I think that this article gives a quite accurate and honest insight in the real state of matters in application-oriented THz research - there are still many wild ideas in circulation that will never work, and it's healthy for the THz community to think a little bit about how we justify our research. I do think, however, that he is too focused on applications that will never work - the real strength of THz radiation lies in my opinion in the fact that it IS a fantastic spectral region for scientific exploration - just because we cannot build T-Ray goggles to look through the clothes of our colleagues does not mean that research and innovation in the THz region is not justified. Clearly, if we cannot look through a kilometer of atmosphere, then why not look at applications that only look through centimeters of atmosphere? Then suddenly many things work again. THz spectroscopy, and in particular THz time-domain spectroscopy with ultrashort THz transients remains a very versatile tool for fundamental investigations in physics and chemistry, and niche applications in industry are being thoroughly tested, for instance by Picometrix".

 At various times, this year I have felt both confused but mostly, simply amazed by the developments in THz. Back in 2008, when I started this blog, I had no idea that it would attract the number of regular readers that come by each day to check out the latest posting. The blog has had visits from 144 countries world-wide, and close to 200,000 web-views. (I didn't start keeping track of the web visits until well into the 2nd year, if you wonder why the web-counter doesn't show quite this many visits).

My goals in starting this blog was to create a location where developments in Terahertz could be tracked and  stored in one location for future reference. I think this blog has done a good job in achieving this goal. More importantly, I wanted to create a location or site where lay persons could learn very basic information about THz, and I really hoped to attract commentary by some of the leaders in the field, so that both readers and I could ask questions.

I'm less satisfied, that I have achieved this last goal, and getting commentary from the scientific community has been akin to pulling teeth. There have been some notable exceptions and Dr. Daniel Mittleman at Rice University, has been a constant and steady source of information for me and readers of this blog. His recent post on TeraNano which was an exclusive to this blog, was a favorite of both readers, and myself.  Thank you, Dr. Mittleman!

I also want to give a special shout-out to Dr. Gerhard Schoenthal, at Virginia Diodes, Inc, (VDI),  who has been kind enough to answer some of my technical questions this year about THz. In regard to VDI, he writes:

"Virginia Diodes continues to see robust interest in mm-wave and THz test and measurement, particularly for VNA Extension Modules up to 1.1 THz. The applications we are seeing are still diverse, ranging from communications and radar to spectroscopy and radio astronomy.

Best regards and happy holidays,

Gerhard"

Gerhard S. Schoenthal • Director of Operations and Microelectronics

Virginia Diodes, Inc. • www.vadiodes.com

979 2nd St. SE, Suite 309 • Charlottesville, VA 22902

I really enjoy being able to provide readers of this blog with original content, and over the years in addition to  Dr. Mittleman's posts, Dr. Irl Duling, Director of Terahertz development at Advanced Photonix,  has been kind enough to share a number of original thoughts, and explanations to various questions I have asked. This year, I also made contact with Dr. Ken O, at UT Dallas about his exciting work in CMOS, and he made exclusive comments on the developments at UT Dallas, for readers here. Similarly, Dr. Anis Rahman, CTO at Applied Research and Phtonics, was kind enough to alert me and readers to here, to a number of timely artcles and blog posting about ARP, and THz, that were posted here earlier this month.

I would also be remiss if I failed to mention, the helpful comments I have received from Dr. Michael Martin, at Lawrence Livermore National Laboratory, who I believe is the editor of the Virtual Terahertz Journal, which is linked on this blog, (on the left-hand column) and also leads the Facebook Terahertz Community group, which I post frequently on. 

To each of these gentlemen, I want to post a hearty thank you, and good luck to each of you in the upcoming year!

Now, I would like to turn my attention to the 10 most notable blog posts of the year. 

1. - 5. CMOS enters the THz lexicon on this blog, coming in from multiple sources. 

I think that the greatest buzz surrounding advances in THz was in the development of solid state THz transistors using CMOS (Complementary Metal-Oxide Semiconductor) technology. I featured no less than 24 blog posts about breakthroughs in this area,  at the University of Wuppertal,  in conjunction with STMicroelectronics, at the University of Texas Dallas, in conjunction with Semiconductor Research Corporation (SRC), by researchers at Cornell University, at Texas Instruments, as well as at the Tel Aviv University,  at Caltech, along with a recent story about similar work at TeraTop, and lastly from  the Leibniz Institutes at IHP, and FBH.

I have to consider these articles and news releases to collectively cover the first five important Terahertz stories of the year. I do note that the work thus far has been in sub-terahertz range, and one reader who knows a great deal wrote me:

"Personally, I think it will be 5 to 10 years before you see the CMOS based THz chips in anything. Obviously, that depends on what you definition of THz is. Lower frequencies will come first and it looks like 60 to 80 GHz is imminent."

6. Genia Photonix signs strategic partnership and development agreement with In-Q-Tel

In the heat of the summer, this story brought a tremendous amount of attention to THz, as Genia Photonix was reported by the online tech magazine Gizmodo, to have developed a new terahertz device which was purportedly so sensitive it would make all other security measures at airports moot. This THz device is supposed to be so sensitive that it can detect the presence of mere molecules of suspicious substances, and could do so all the way from a distance of 50 meters. http://terahertztechnology.blogspot.com/search?q=genia

(I have some skepticism about these claims but my efforts to get any comment from Genia were simply ignored-I guess we will learn more this year about this remarkable device).

7. Northrup Grumman & Darpa makes advances in developing solid-state THz devices using monolithic microwave intergrated circuits
Darpa appears to be taking a somewhat different avenue in it's efforts to create a sold state THz device employing MMIC technology. At present progress remains in the sub-millimeter wavelength.http://terahertztechnology.blogspot.com/search?q=darpa (Please, note that this article reports development in the 850 GHz range, which is significantly higher than what is reported in the first category above.) 

8. On April 16th, 2012, I reposted the article "Viewpoint: Stimulated Near-Infrared Light Emission in Graphene" written by author Ilias Perakis, 
http://terahertztechnology.blogspot.com/2012/04/viewpoint-stimulated-near-infrared.html
This article discusses the work "Femtosecond Population Inversion and Stimulated Emission of Dense Dirac Fermions in Graphene". which I reposted here:
http://terahertztechnology.blogspot.com/2012/11/manipulating-light-with-single-layer-of.html
The Perakis article continues to be a reader favorite and each week it typically continues to be the most widely read of the 849 blog posts found here.

9. Work with Graphene, continues to revolutionize Terahertz
If CMOS attracted attention this year, it was only surpassed by reader interest in developments using graphene . There were multiple articles I could mention, but only have space for a few. One of the most interesting ones was Agilent Technologies announcement it was opening a Terahertz Measurement Research Lab, in conjunction with the University of Leeds. Graphene will play an integral role as it was noted that; "In the new field of graphene, the network analyser will allow the university staff to perform on-wafer terahertz measurements of transistors, THz biosensors, magnetic storage elements, THz spin-switches and novel acoustoelectric devices. It will also be used to characterise THz passive components such as filters, waveguides, fibres and antennas."http://terahertztechnology.blogspot.com/2012/10/agilent-technologies-and-university-of.html  
Dr. Daniel Mittleman's post regarding the presentations at TeraNano Japan also focused  in part on the role graphene will play in THz developments in the future.
Work with graphene at NASA, ASTAR and the University of Denmark/University of Wuppertal were also equally significant.http://terahertztechnology.blogspot.com/search?q=TeraNano

10. InView obtains patents on it's compressive sensing camera,
InView, which is a spin off from Rice University announced it's patent of a compressive sensing camera, which will be high-performance, and cost effective, because they will require a much smaller number of photodiode detectors than is required in a conventional camera, and are well suited for security, surveillance and maritime navigation applications because of their unique ability to see through impairments such as fog, haze, smoke and dust.
http://terahertztechnology.blogspot.com/2012/06/inview-issued-patent-on-compressive.html

Lastly, I would be remiss in not mentioning the continuing work of Dr.'s Duling and Zimdars, at Advanced Photonix, (API),  in continuing to trailblaze the way, in the actual commercialization of THz, here at the terrestrial level and in a variety of commercial applications on the factory floor. 

As an investment Advanced Photonix, continues to sadly disappoint, with the stock price dropping to an all time low, of .38, a share. In response,  the faithful retail investment community has taken a more proactive stance in letting Management and the Board of Directors know about their dissatisfaction.

 The reality is that most startup ventures in emerging technology fail, however API appears to have turned the corner with a geometric increase in sales of their proprietary T-Gauge to a number of factories, and in a variety of settings. In July I noted that the very widely-read authoritative publication,  Jane's Airport Security and Safety Review, featured a story about Advanced Photonix, anomaly detection device, which it has named the "Saf-T-Chek". In this article Dr. Duling, director of terahertz business development for API, noted that the anomaly detection system will allow TSA security personnel to discontinue the practice of physically "patting-down" passengers after initial scanning by threshold airport security systems reveals an anomaly on the person's body, which might be a concealed object, (or simply a person wearing religious headgear which can't be removed.).
The system's terahertz pulse which covers a wide bandwidth from 20 GHz, to almost 4 THz, and is capable of detecting a wide range of chemical or biological signatures, which it then compares against the library of spectroscopic signatures it has been programmed to detect.
Duling indicated that the accuracy of the detection program was very high, and that there is a low false alarm rate. The detection system is based upon proprietary algorithms written by Duling and API engineers for use in the system's internal semiconductors.
Jane's reports that at present, the system when purchased in bulk will retail at around $70,000 per unit.
Jane's article also reports that the device is relatively maintenance free, and because it uses automated software user training is very minimal, (5-10 minutes) to achieve operator proficiency.
http://terahertztechnology.blogspot.com/2012/07/june-2012-ihs-janes-airport-review.html
The uses for the Advanced Photonix new T-Gauge® system are for the process and quality control markets in industrial manufacturing. The firm has already signed several new value added resellers that should help it secure a solid market share. These agreements include one with Automation and Control Technology Inc. (ACT) and Thermo Fisher Scientific. The Homeland Security market is the wild card application for Advanced Photonix new terahertz product called the Saf-T-Chek ADS©. This next generation system for non-contact, non-imaging inspection for potential threat anomalies under clothing, is just the latest opportunity for Advanced Photonix.
As a retail investor in API, I remain hopeful that 2013 will finally see Advanced Photonix, turn the corner on profitability.
There are many other companies, and blog posting not mentioned here and if you would like to have your work mentioned please write me and share your thoughts.I do note that  my efforts to communicate with many are simply ignored, leaving the lay investing world to simply speculate about the developments in this exciting technology. Thank you for reading, and have a happy and prosperous 2013!

Advanced Photonix Anomaly Detection Device, T-Ray 5000, with hand-held applications expected to ship to TSA by the end of March

 

  •Touchscreen 

•Internal processing

•Integrated umbilical

•35 lbs

•0 – 50 °C

• Line-scan width 3 in.
  
  • – Gap > 500 mils
    
  • – Step 0 to > 250 mils
• Stand-off approx. 3 in.
  
• 4 to 10 B-scans per second
  
• Laser projection reticule aids operator positioning
  
• 3.5 in. high, 5.25 in. wide, 6 in. long (handle 4.2" high)
  
• 240 x 320 pixel backlit color LCD touch-screen, 3.78" diagonal
  
• 15 m umbilical
  
• Weight 3 lbs. 

My Note: It is my understanding that Advanced Photonix (API)  is on track to ship the Transportation Security Department (TSA) funded, Anomaly Detection Device, (pictured in the top photo above), to the TSA by the end of this month. Some may not know, or have forgotten, that this project was financed in conjunction with In-Q-Tel, which also  took a sizeable equity position in API.
API has designated this device the "T-Ray 5000", and as shown above it only weighs 35 pounds, and allows for hand-held scanning for both security as well as industrial quality control purposes. Pretty exciting for the API retail community. Cheers to Dr's Irl Duling &  David Zimdars, Rob Risser, Rick Kurtz, Steve Williamson, and the gang at API/Picometrix. 
Here is the original press release to this story from November of 2010:

ANN ARBOR, Mich., Nov. 5, 2010 /PRNewswire/ -- Advanced Photonix (API) today announced an agreement in principle withIn-Q-Tel (IQT) to engineer a low cost terahertz anomaly detectiondevice, and deliver multiple systems for evaluation. IQT, a not-for-profit, strategic investment firm that works on behalf of the U.S. Intelligence Community, is focused on identifying new and emerging commercial technologies that have the potential to give its customer agencies mission-advantage today and in the future. 
"We are excited to have reached an agreement in principle with IQT to use our technology currently found in the T-Ray® 4000 to produce a low cost derivative for the security market," said Richard Kurtz, CEO of API. "With the help of IQT we expect to work with the end users, accelerate the testing and evaluation, and deliver multiple fully functioning systems for evaluation within one year. The fact that the T-Ray® platform is being considered for this mission speaks volumes to the performance of our system."

The T-Ray® 4000 produces ultrashort pulses of terahertz light that allow a variety of unique and novel applications to be investigated. The system's patented fiber coupling permits automated or manual positioning of the sensor heads. As a result, users can examine any size object in place, thereby eliminating the need to fit the object into a specialized sample chamber. The excellent signal-to-noise ratio of the T-Ray® platform allows even thick samples to be scanned effectively.

As a strategic partner for the Intelligence Community (IC), IQT understands complex customer requirements and constantly surveys the leading edge of the commercial marketplace in order to identify, adapt, and deliver technology solutions to its customers. This technology development agreement is designed to apply API's terahertz technology to anomaly detection. Delivered in the form of a handheld device or "wand," this technology is intended to detect external objects on the body of a person without the need for imaging or a lengthy physical pat-down procedure, avoiding the associated privacy concerns and time-consuming image review.

"We are pleased to be partnering with API to provide this important technology capability to our customers," said William Strecker, Executive Vice President of Architecture & Engineering and CTO at IQT. "Upon execution, this agreement will allow us to work together with API to adapt the product to fit customer needs." 

The proposed $1,800,000 development program is designed to advance API's product to accommodate increased anomaly detection needs. The Transportation Security Administration (TSA) is providing funding to IQT for this development effort.

The agreement in principle includes a royalty agreement that is based on sales to entities other than the U.S. Government of the commercialized anomaly detection device developed under this technology development agreement. The royalty has both a monetary cap and time limit associated with all sales.

Separately, API also announced that it had entered into a Securities Purchase Agreement (SPA) with IQT pursuant to which API agreed to issue and IQT agreed to purchase approximately 198,524 shares of API's Class A Common Stock at a price of $1.0074 per share. The closing of the SPA is subject to receipt of NYSE Amex approval of an additional listing application covering the shares of Class A Common Stock issued in connection with the SPA (the Listing Application) and other closing conditions customary for transactions of this nature.

Execution of definitive documentation with respect to the proposed development agreement and royalty agreement is anticipated within the next ten business days and is subject to NYSE Amex's approval of the Listing Application and the satisfaction or waiver of the closing conditions to the SPA.

Picometrix hand-held Terahertz imaging -In-space NDI Technology workshop

http://www.nasa.gov/pdf/626494main_3-3-A_Zimdars.pdf

Dr. David Zimdars of Picometrix -2012 In-Space Non-Destructive Inspection Technology Workshop Presenter

2012 In-Space Non-Destructive Inspection Technology Workshop Presenter

---

Dr. David Zimdars Picometrix, LLC Manager of Terrahertz R&D dzimdars@picometrix.com (734) 865-5639 www.picometrix.com

Session 3A Presentation 3 "Hand Held Terahertz Imaging" Demo: No | Poster: No One-on-One Table: No

Abstract: Hand held time-domain terahertz (TD-THz) non-destructive evaluation (NDE) systems can be used to inspect space flight structures such as inflatable space habitats, thermal protection systems (TUFI-type tiles, SOFI TPS), and other components for voids, disbonds, and damage such as tearing and micro-meteorite impact. THz radiation in the range of 0.1 THz to 3 THz can penetrate these materials, and can be used to generate sub-surface images of these otherwise opaque or hidden structures. TD-THz reflection tomography is a single sided method, so it can inspect an inflatable habitat from the inside. Because the method is electromagnetic, it is inherently non-contact, and can penetrate vacuum (unlike ultrasound tomography), which is a significant advantage for the space based inspection of delicate structures such as polyurethane or silica foam TPS. The method of TD-THz reflection tomography employs near single-cycle sub-picosecond electromagnetic impulses that are generated and detected by the TD-THz instrument. These THz impulses are focused onto the object to be inspected. A small portion of the THz impulse reflects from the boundary of each material interface. These reflected pulses are separated in time, proportional to the thickness between the layers. The reflected TD-THz waveform is recorded, and the waveform is a representation of the sub-surface structure. In many ways, TD-THz reflection tomography is like an electromagnetic analog to ultrasound tomography (UT). Background: Dr. David Zimdars is the Manager of Terahertz Research and Development at Picometrix. Since 2001, Dr. Zimdars has been the research and development manager for all terahertz scientific, industrial and homeland security product development contracts, terahertz analytical/imaging applications development, and terahertz manufacturing quality control applications development. He was a co-developer of the compact fiber optic coupled T-Ray 4000 modular time domain terahertz instrumentation system. Picometrix T-Ray 4000 and QA-1000 terahertz imaging systems have been deployed by NASA Michoud / Lockheed Martin to scan the space shuttle external fuel tank sprayed on foam insulation and orbiter thermal protection systems. The QA-1000 has been awarded the 2004 Photonics Spectra Circle of Excellence Award. He was a co-developer of the T-Ray 2000 THz spectroscopy and imaging system. Released in the in fall 1999, the T-Ray 2000 was the world’s first commercially available time domain THz instrument. The T-Ray2000, due to its unique capabilities and innovative fiber coupled design, was given an R&D 100 award for and a Photonics Spectra award. He currently has over 32 papers and publications and several patents and patents pending. Education: Stanford University, Ph.D. (Chemistry - Chemical Physics), 1996 Rocky Mountain College, B.S. (Chemistry), 1989 Professional Experience:Pres-2001 Manager of Terahertz R&D, Picometrix, LLC, Ann Arbor, MI 2001-1999 Research Scientist, Picometrix Inc., Ann Arbor, MI 1999-1996 Postdoctoral Researcher, Dept. of Chem., Columbia Univ., New York

Find this article at:

http://www.nasa.gov/offices/nesc/workshops/in_space_Bio_zimdars.html

My Note: Thanks for finding this link to:

bucktailjig05

Picometrix obtains Phase II from NASA to space qualify a compact TD-THz, control unit design to be used for in-orbit inspections of inflatable habitats and thermal protection systems

NASA Phase II

(MY NOTE: Thanks to message board poster bucktailjig05 for bringing this to my attention.)

SBIR 2010

SBIR 2010 Phase II Selection Announcement Announced on December 19, 2011

National Aeronautics and Space Administration
Small Business Innovation Research (SBIR) Program

2010 Phase 2

Proposals Selected for Negotiation of Contracts

FIRM LIST

Picometrix, LLC
2925 Boardwalk Drive
Ann Arbor, MI 48104-6765
Marsha Gilbert (734) 864-5600
10-2-X5.04-8154 LaRC
Miniaturized Time Domain Terahertz Non Destructive Evaluation for In-Orbit Inspection of Inflatable Habitats and Thermal Protection Systems

PROPOSAL NUMBER:	10-2 X5.04-8154
PHASE 1 CONTRACT NUMBER:	NNX11CH15P
SUBTOPIC TITLE:	Spaceflight Structural Sensor Systems and NDE
PROPOSAL TITLE:	Miniaturized Time Domain Terahertz Non Destructive Evaluation for In-Orbit Inspection of Inflatable Habitats and Thermal Protection Systems

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Picometrix, LLC
2925 Boardwalk Drive
Ann Arbor, MI 48104 - 6765
(734) 864-5600
PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
David Zimdars
dzimdars@picometrix.com
2925 Boardwalk
Ann Arbor, MI 48104 - 6765
(734) 864-5639
Estimated Technology Readiness Level (TRL) at beginning and end of contract:
Begin: 4
End: 6
TECHNICAL ABSTRACT (Limit 2000 characters, approximately 200 words)
Picometrix's time-domain terahertz (TD-THz) non-destructive evaluation (NDE) technology could be used to inspect space flight structures such as inflatable space habitats, thermal protection systems (TUFI-type tiles, SOFI TPS), for voids, disbonds, and damage such as tearing and micron-meteorite impact. The current instrumentation paradigm is that a multi-purpose TD-THz control unit is used to provide common drive, data acquisition, and analysis functionality to interchangeable sensors and imaging which connect to the control unit with a fiber-optic/electrical umbilical. However, the current COTS control unit is substantially larger and heavier than would be desirable for a space-flight capable unit. In Phase II we will construct a prototype compact TD-THz control unit with a fiber optically coupled remote compact TD-THz reflection tomography sensor based on the Phase I designs. At the end of a successful Phase II, and transitioned into Phase III, we envision that a hand-held A or B-Scan NDE imager could attach to a control unit, sufficiently robust for spaceflight, no larger than a shoebox. In Phase II, it should be possible to reduce the size of the control unit to approximately 1/3 of the current values to, for example, 14 in. X 10 in. X 4 in. and 15 pounds.
POTENTIAL NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
At the end of a successful Phase II, the goal would be to space qualify the compact control unit design in Phase III so that it could be used for in-orbit inspections of inflatable habitats and thermal protection systems. In addition, THz NDE instrumentation will be valuable in characterizing the aging and durability of aircraft and spacecraft materials and components. Materials include ceramics, foams, Kevlar, Zylon, and other non-conductive polymer matrix composites. Additional NDE applications include inspection of soft shell fan containment, thermal protection systems, and composite overwrap pressure vessels.
POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (Limit 1500 characters, approximately 150 words)
Ceramics, foams, and polymer matrix composites are used in automobile and ships and many other consumer and industrial products. A compact TD-THz imaging system could be used inspect automobile dashboards, inspect for delamination of printed circuit boards, inspect of pipe insulation, as well as inspect manufactured parts such as pure plastic and paper products. A compact TD-THz imager benefits homeland security applications under development such as personnel and luggage inspection for concealed weapons and explosives (in luggage, shoes, etc.).

PRODUCTION PROCESS MONITORING OF MULTILAYERED MATERIALS USING TIME-DOMAIN TERAHERTZ GAUGES

 

MY NOTE: MESSAGE BOARD POSTER bucktailjig05 BROUGHT THIS PDF FILE TO MY ATTENTION. I WAS ABLE TO CONVERT THE FIRST COUPLE OF PAGES TO A FORMAT YOU CAN READ HERE. THE REST CAN BE ACCESSED VIA THE LINK BELOW.

http://b-dig.iie.org.mx/BibDig/P10-0372/cdr_pdfs/indexed/stage4_copyr/564_1.pdf

David Zimdars, Irl Duling, Greg Fichter, and Jeffrey White

Picometrix LLC, 2925 Boardwalk Dr., Ann Arbor, MI 48104 USA

ABSTRACT.    The results of both a laboratory and factory trial of a  time-domain terahertz (TD-THz) multi-layer gauge for on-line process monitoring are presented.  The TD-THz gauge is demonstrated on a two layer laminated plastic insulation material.   The TD-THz gauge simultaneously measured the total and the individual layer thicknesses. Measurements were made while transversely scanning across a 12 foot wide sheet extruded at high speed in a factory environment.  The results were analyzed for precision, accuracy, and repeatability;  and demonstrated that  the TD-THz  gauge  performed  in an equivalent  or superior manner to existing ionizing radiation gauges (which measure only one layer).   Many dielectric materials  (e.g.,  plastic,  rubber, paper, paint) are transparent  to THz pulses, and the  measurement of a wide range of samples is possible.

Keywords: Terahertz, NDE

PACS: 81.70.Fy

INTRODUCTION

The use of time-domain terahertz (TD-THz) non destructive evaluation (NDE) imaging has been well established  as a useful sub-surface  inspection method for  aerospace materials such as non-conductive polymer matrix composites; and polymer, ceramic, and silica thermal protection materials[1-4].  In the current work, we expand the application of TD-THz methods and instrumentation to on-line factory process monitoring of thickness.  We present the results of both a laboratory and factory trial of a reflection TD-THz multi-layer thickness gauge which measured  both  the  total  and individual  layer  thicknesses  of  a  multi-layer  plastic  laminate material used in commercial building construction.   Data was collected both in the laboratory and  in   a  factory  demonstration  continuously  over  several  days,  showing  the  precision, accuracy, and long term stability of the instrument.

The multi-layer plastic laminate material measured in this demonstration is widely used in commercial building construction.   The material is a two layer sandwich of thermo-plastic olefin sheets, with a fabric material separating the middle layer; which is pressed and laminated in large sheets.    The layers must be thick enough to meet specifications but not so thick as to waste material.   While the  demonstration was made on a specific type of multi-layer sheet product,  the   TD-THz   gauge   is  widely   suitable   for  many  other   products.   In  general, measurements may be made on most dielectric materials (e.g., plastic, rubber, paper, paint).

The legacy measurement technology currently employed by the manufacturers  of the multi-layer plastic  construction  material  is generally  based  on  ionizing  radiation.  A single ionizing radiation  gauge (gamma, beta or x-ray gauge) can  measure only the total material thickness.    If  a  multi-layer  product  is  being  manufactured,  then  more  than  one  ionizing

 radiation thickness gauge must be deployed on the line, and the thickness of the second layer is inferred by subtracting the first layer thickness from the total.   To achieve the best accuracy, both measurements must be made on the same location,  requiring sophisticated  timing and coordination of the speed of the line with the scanning of the gauges.

The   TD-THz  gauge  concept  can  measure  the  thickness  of  both  layers   of  the construction material simultaneously, replacing one or more ionizing radiation gauges with a single TD-THz gauge.   Furthermore, in contrast to the ionizing radiation of x-ray, gamma, and beta gauges, THz energy presents no hazard to operators or bystanders.   There is no need for ionizing  radiation   safety   precautions,   security   to  prevent  theft  of  radioactive   material, government  mandated record  keeping,  or special  costly  end  of life  disposal  of radioactive material.

The  TD-THz  instrumentation  employed utilizes  miniature fiber  optic  interconnected remote THz transmitter and receiver modules.  These modules are connected to a rack mounted TD-THz  control  and  analysis  unit  by  flexible  cables  up  to  30  m  long.    This  allows  the construction  of  a  small,  solid-state  TD-THz  gauge  sensor  head  which  can  be  mounted  in existing ionizing radiation gauge mounts.  The software developed is similar in user interface and simplicity to the existing ionizing radiation gauge software, but with the additional multi- layer measurement functionality.  This approach will allow users of the gauge to easily replace existing ionizing  radiation  gauges  with TD-THz  gauges,  and in addition  receive  the added capability of multiple layer measurements.

TD-THz Reflection Measurement of Multi-Layer Thickness

TD-THz instrumentation makes measurements with ultra-short near single cycle pulses of electromagnetic radiation (approximately 0.5 to 1 ps width).   This  corresponds  to a very wide bandwidth from (0.1 to >3 THz).   The instrument records  a high fidelity trace of the measured electric field vs. time repeated in a waveform window, similar to a very high speed sampling oscilloscope.

The   method   of   TD-THz   measurement   of   multiple   layer   materials   is   shown schematically in Fig. 1 for heuristic purposes.   A pitch-catch configuration of transmitter and receiver is shown on the left.  The transmitter sends a TD-THz pulse into the two layer sample. Index of refraction discontinuities at each layer boundary will cause Fresnel reflections of the input pulse.