Thursday 28 July 2011

Second international terahertz (THz) application workshop 11- 13 October 2011 Dayton, Ohio - REMINDER

ONLY 3 SPACES LEFT!


This workshop aims at bringing together new and existing terahertz instrumentation users. It is an opportunity to share knowledge and understating of the technology.
THz systems will be used for hands on demonstration of the equipment. Data processing and analysis techniques will be also extensively discussed.
The workshop will span throughout two days, with the opportunity of remaining a third day on –site for further hands-on demonstrations.
Throughout the two days there will be extensive opportunities for the users to discuss their projects in detail and to establish links to experts in this field.

Topics will include:
Introduction to terahertz spectroscopy
Data Analysis
Terahertz imaging
Hands-on use of terahertz equipment

Anyone wishing to to learn more about terahertz applications should attend this workshop!

Find more information on TeraView's website:



Wednesday 27 July 2011

Terahertz Pulsed Imaging as a PAT Tool for Evaluating the Effect of Coating Methods and Application of Stress Conditions on Applied Film Quality

In Proceedings of the 1st Electron. Conf. Pharm. Sci.

Sciforum Electronic Conferences Series, 2011, b003:1-10

Haaser, M.; Gordon, K.; Pepper, M.; Rades, T.; Rantanen, J.; Strachan, C.; Taday, P.; Zeitler, J.; Naelapää, K. 



Abstract: Film coating process development and applied film quality have been in the focus of the pharmaceutical industry for decades. Many techniques have been used to investigate and characterise complex film coating structures. Recently, terahertz pulsed imaging (TPI) has been introduced to study and understand the quality of film coatings. In this study, the effect of two different film-coaters , a fluid bed (Combi Coata, Model CC1/LAB, Niro Atomizer, Denmark) and a drum coater (Hi-Coater, HCT 20, Lödige Mascinenbau GmbH, Germany) on the applied film quality was determined by TPI (TPI imaga 2000, TeraView Ltd, Cambridge, UK). In addition to the coating application under recommended conditions, stress conditions were applied and investigated; e.g. high spray rate, simulated nozzle block during the coating process, and varying curing times after coating. From the terahertz time-domain waveforms, maps of the terahertz electricfield peak strength (TEFPS), interface index (TII) and coating thickness (CT) were successfully derived. SEM was used as a complimentary technique to increase the insight into the various coating characteristics. The results showed lower TEFPS values for samples coated by the fluid bed device, indicating a rougher coating surface than samples coating by the drum coater. Although the amount of coating applied was found to be the same, the mean CT for the fluid bed coated samples was higher. Furthermore, it was possible to distinguish an interface between the subsequent coating layers in the CT maps (generated by a coating liquid application stop), which couldn't be resolved by SEM for all samples. The different process conditions in both pieces of equipment are considered to be reason for this observation, as well as the difference found in the TII values (interface coating/core) for tablets coated by the two methods, respectively. In good agreement with previous studies, the overall thickness of the coating layer was systematically thinner around the centre band compared to the top and bottom surfaces. TPI can be considered to be a sophisticated PAT tool for gathering information, and increasing the understanding of complex film coating structures.
Keywords: Terahertz Pulsed Imaging (TPI), film quality, coating

Tuesday 26 July 2011

Total variation deconvolution for terahertz pulsed imaging

Inverse Problems in Science and Engineering

Volume 19Issue 2, 2011

DOI: 10.1080/17415977.2010.550045


Abstract

In terahertz pulsed imaging (TPI), a deconvolution process is usually applied as an inverse operation to extract the sample impulse function for further imaging or spectroscopic analysis. Often, such deconvolution is achieved by direct inverse filtering (IF) or IF with a coupled low-pass or double Gaussian filter. However, the low-pass or double Gaussian filter cannot cope well with both suppressing noise and retrieving localized terahertz pulses and they often result in over-smoothing. Here, we apply the iterative total variation method to the deconvolution process in TPI with a view to enhance the sample impulse function and generate better terahertz images. Experiments with both simulated and raw data validate a better performance for the proposed approach.
·        View full text
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Keywords

·      inverse filtering
·      double Gaussian filter

Friday 22 July 2011

Terahertz absorption spectra of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) polymorphs

Christopher T. Konek, Brian P. Mason, Joseph P. Hooper, Chad A. Stoltz and John Wilkinson
Indian Head, Naval Surface Warfare Center, 4104 Evans Way, Suite 102, Indian Head, MD 20640, USA

Abstract

Interest in terahertz spectroscopy of organic compounds has been driven by its potential utility as a stand-off detection technology for explosives. Much work has focused on identifying the spectral signatures of explosives compounds and understanding the molecular origin of the complex, low-frequency modes in the terahertz regime. We present distinct absorption spectra in the terahertz region for polymorphs of the secondary high explosive 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). For α-HMX, we couple experiments to solid-state density functional perturbation theory (DFPT) calculations, and find excellent agreement. This work underlines the importance of careful sample preparation when examining spectra and comparing experimental work with calculations.

Graphical abstract

HMX polymorphs are investigated with terahertz spectroscopy. We demonstrate good agreement between DFPT calculation and the experimental spectrum of α-HMX.


 http://www.sciencedirect.com/science/article/pii/S0009261410002204

Note from the Blog's Editor: Measurements in this paper were done using TeraView's Spectra 3000.

Monday 18 July 2011

Terahertz pulsed spectroscopy and imaging for pharmaceutical applications: A review


Yao-Chun Shen
Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, UK

Available online 13 January 2011. 

Abstract

The terahertz region of the electromagnetic spectrum spans the frequency range between the infrared and the microwave. Traditionally the exploitation of this spectral region has been difficult owing to the lack of suitable source and detector. Over the last ten years or so, terahertz technology has advanced considerably with both terahertz pulsed spectroscopy (TPS) and terahertz pulsed imaging (TPI) instruments now commercially available. This review outlines some of the recent pharmaceutical applications of terahertz pulsed spectroscopy and imaging. The following application areas are highlighted: (1) discrimination and quantification of polymorphs/hydrates, (2) analysis of solid form transformation dynamics, (3) quantitative characterisation of tablet coatings: off-line and on-line, (4) tablet coating and dissolution, (5) spectroscopic imaging and chemical mapping. This review does not attempt to offer an exhaustive assessment of all anticipated pharmaceutical applications; rather it is an attempt to raise the awareness of the emerging opportunities and usefulness offered by this exciting technology.


Friday 15 July 2011

Terahertz sensing in corneal tissues

J. Biomed. Opt. 16, 057003 (May 10, 2011); doi:10.1117/1.3575168



David B. BennettZachary D. TaylorPria TewariRahul S. SinghMartin O. Culjat, and Warren S. Grundfest
University of California, Los Angeles, Center for Advanced Surgical and Interventional Technology, Los Angeles, California 90095
Daniel J. SassoonR. Duncan Johnson, and Jean-Pierre Hubschman
University of California, Los Angeles, Jules Stein Eye Institute, Los Angeles, California 90095
Elliott R. Brown
Wright State University, Department of Physics and Electrical Engineering, Fairborn, Ohio 45435

This work introduces the potential application of terahertz (THz) sensing to the field of ophthalmology, where it is uniquely suited due to its nonionizing photon energy and high sensitivity to water content. Reflective THz imaging and spectrometry data are reported on ex-vivo porcine corneas prepared with uniform water concentrations using polyethylene glycol (PEG) solutions. At 79% water concentration by mass, the measured reflectivity of the cornea was 20.4%, 14.7%, 11.7%, 9.6%, and 7.4% at 0.2, 0.4, 0.6, 0.8, and 1 THz, respectively. Comparison of nine corneas hydrated from 79.1% to 91.5% concentration by mass demonstrated an approximately linear relationship between THz reflectivity and water concentration, with a monotonically decreasing slope as the frequency increases. The THz-corneal tissue interaction is simulated with a Bruggeman model with excellent agreement. THz applications to corneal dystrophy, graft rejection, and refractive surgery are examined from the context of these measurements.


Note from the Blog's Editor: some of the measurements in this paper were done using a Spectra 3000

Thursday 14 July 2011

RSC EVENT - Recent Developments in Terahertz Spectroscopy and Imaging


Event Details    

Recent Developments in Terahertz Spectroscopy and Imaging
Terahertz radiation, the part of the electromagnetic spectrum between microwaves and infrared radiation, has unique properties in that it easily penetrates through most polymeric materials and is therefore an exciting new tool to study such materials. As well as being a non-destructive imaging probe, in organic molecular crystals terahertz radiation interacts with vibrational modes that extend across large domains of a crystal lattice. This makes terahertz spectroscopy unique: even though it is possible to excite molecules using a variety of energies it is only through the careful selection of the low energy in the terahertz range that it is possible to selectively excite crystal lattice vibrations and study the presence and nature of interactions between molecules
Date: 27 October 2011 10:00 - 16:00
Event Subject(s): Analytical
Physical

Venue

RSC, Thomas Graham House
Barton Room
Science Park
Milton Road
Cambridge
CB4 0WF
United Kingdom


Monday 11 July 2011

TeraView expands customer base in Europe

TeraView Cambridge, United Kingdom – 11 July 2011

TeraView (http://www.teraview.com/), the pioneer and leader in Terahertz solutions and technology, has successfully delivered two systems to Military University of Technology (MUT) in Poland.

Established in 1951 MUT is one of the country’s most prestigious research institutes, with over 8000 students and over 385 academic staff.

TeraView supplied its TPS spectra 3000 system with stand-off explosives detection module and accessories to MUT for Terahertz research and materials characterisation. In addition to this system, TeraView was also chosen to supply a second fibre-fed scanning system with multiple gantry options for research into Terahertz imaging and non-destructive testing. Both systems were chosen in open tender over competitors, due to ease of use, superior performance and the Company’s track record with its existing customers.

The sale adds to TeraView’s growing installed base in Europe, and helps strengthen its position as the market leader for Terahertz systems.

Dr Don Arnone, TeraView’s CEO stated 'This multiple sale to a prestigious institution highlights TeraView’s position as the major supplier of Terahertz systems and indicates the continued growth in the use of Terahertz as a valuable research tool.'

Friday 8 July 2011

Recent paper: terahertz pulsed imaging of human colonic tissue


Terahertz pulsed imaging of freshly excised human colonic tissues


Caroline B Reid1, Anthony Fitzgerald2,5, George Reese3, Robert Goldin4, Paris Tekkis3, P S O'Kelly5, Emma Pickwell-MacPherson6, Adam P Gibson1 and Vincent P Wallace2,5




ABSTRACT

We present the results from a feasibility study which measures properties in the terahertz frequency range of excised cancerous, dysplastic and healthy colonic tissues from 30 patients. We compare their absorption and refractive index spectra to identify trends which may enable different tissue types to be distinguished. In addition, we present statistical models based on variations between up to 17 parameters calculated from the reflected time and frequency domain signals of all the measured tissues. These models produce a sensitivity of 82% and a specificity of 77% in distinguishing between healthy and all diseased tissues and a sensitivity of 89% and a specificity of 71% in distinguishing between dysplastic and healthy tissues. The contrast between the tissue types was supported by histological staining studies which showed an increased vascularity in regions of increased terahertz absorption.

http://stacks.iop.org/0031-9155/56/4333 



Caroline B Reid et al 2011 Phys. Med. Biol. 56 4333

Monday 4 July 2011

2011 Joule Medal and Prize


2011 Joule Medal and Prize

Dr Donald D Arnone
TeraView Ltd.
For his pioneering work in the science, technology and applications of terahertz radiation.
Dr Arnone has acquired an international reputation for his pioneering work in taking terahertz radiation from a laboratory demonstration to an important, previously unsuspected, diagnostic technique arousing world-wide scientific and industrial interest. Early work at Lucent showed that femtosecond excitation of a semiconductor resulted in emission of terahertz radiation and primitive imaging was demonstrated. Working at Toshiba Research Europe, Cambridge, Arnone improved methods of generation and detection, initially for basic semiconductor studies. Then in 1999 he obtained the first terahertz image of human tissue - a tooth- showing decay and enamel wear more clearly than X-Rays, subsequently investigating excised cancerous skin samples demonstrating absorption differences between skin cancer and healthy tissue.
In 2001 TeraView was established with Arnone as CEO, he led a programme improving both hardware and software for the pharmaceutical industry resulting in significant breakthroughs in non-invasively detecting polymorphic changes in active ingredients in tablets, a major problem in the industry with serious safety implications. Internal interfaces of tablets were resolved with important relevance for high added value tablets such as anti-cancer where controlled release of ingredients is imperative to prevent harmful side-effects. Arnone’s team have subsequently worked with over 20 of the world’s leading pharmaceutical companies on improving tablet efficiency and safety. New methods for predicting dissolution properties have also been found.
Other areas which he has pioneered have been security imaging and spectroscopic identification of explosives and toxic gases. An advanced fault determination technology has been developed for semiconductor chips and terahertz instrumentation is undergoing clinical trials in Guys Hospital London for determination of tumour margins during surgery The development of terahertz has been a remarkable demonstration of applied physics with important applications based on fundamental principles, Arnone’s team and company are now the international leaders in this important, new emerging industry.