Navigation Links
Checking people at airports -- with terahertz radiation
Date:9/18/2008

This press release is available in German.

Within the last few years the number of transport checks above all at airports has been increased considerably. A worthwhile effort as, after all, it concerns the protection of passengers. Possibilities for new and safe methods of transport checks are offered by terahertz radiation. Before this radiation can be used for this purpose, however, it has to be measured quantitatively, so that damage to health caused by radiation can be ruled out. The exact measurement of this type of radiation has now been successfully undertaken by the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, for the first time.

Radiation in the THz range (with wavelengths from 30 m to 3000 m and frequencies from 0.1 THz to 10 THz) penetrates clothing and many other organic materials and furthermore offers spectroscopic information on safety-relevant materials such as explosives and pharmacological substances. The broad spectrum of the possible applications extends from security check to the investigation of the spatial and/or time structure of the electron packages in the storage rings for synchrotron radiation production and in free-electron lasers, for which the receivers of the German Electron Synchrotron DESY characterized here are used.

The complete information on the THz spectra can only be determined with detectors of known spectral responsivity. Up to now, the integral responsivity of the respective detectors and their spectral distribution are still largely unknown. The PTB has now for the first time determined the spectral responsivities of two THz detectors in the wavelength range from 50 m to 600 m with the aid of cavity radiators.

In order to make available spectral radiation fluxes in the THz range, calculable according to Planck's radiation law, the PTB uses two THz cavity radiators at different temperatures in connection with THz band and longwave-pass filters. The interior surfaces of the radiators are provided with a special coating which possesses a known and high emissivity also in the THz range and thus enables the calculability of the radiation incident on the detector. In order to obtain a sufficiently spectral purity of the THz radiation, a suppression of the infrared radiation of more than nine orders of magnitude is necessary.

By using an FT-IR spectrometer, the transmittance for all filter combinations used was accurately determined in the wavelength range from 0.8 m to 1700 m. Due to the calculable radiation of the cavity radiators and the known transmittance of the filters, it is possible to accurately determine the spectral radiation fluxes and thus determine the spectral absolute responsivities of THz receivers for the first time. Such absolutely characterized receivers will in future be utilized, e.g., both at the Metrology Light Source of the PTB to investigate the THz radiation produced there and in the investigation of the effect of THz radiation on the biological cell cycle.


'/>"/>

Contact: Berndt Gutschwager
berndt.gutschwager@ptb.de
49-303-481-7323
Physikalisch-Technische Bundesanstalt (PTB)
Source:Eurekalert

Related biology news :

1. Older people who diet without exercising lose valuable muscle mass
2. Genes may make some people more prone to anxiety
3. People with heart disease still have trouble controlling blood lipid levels
4. Robotics research: Enhancing the lives of people with disabilities
5. Simian foamy virus found in several people living and working with monkeys in Asia
6. Why do people vote? Genetic variation in political participation
7. Nitric oxide regulates plants as well as people
8. People with diabetes may have all natural citrus supplement
9. Veterinary college researcher studying brain tumors in people and animals
10. Most people believe smallpox not an extinct disease
11. Impacts of fossil fuels on fish and people
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/13/2016)... 2016  IMPOWER physicians supporting Medicaid patients in ... clinical standard in telehealth thanks to a new partnership ... platform, IMPOWER patients can routinely track key health measurements, ... index, and, when they opt in, share them with ... a local retail location at no cost. By leveraging ...
(Date:3/29/2016)... 2016 LegacyXChange, Inc. (OTC: ... SelectaDNA/CSI Protect are pleased to announce our successful effort ... variety of writing instruments, ensuring athletes signatures against counterfeiting ... from athletes on LegacyXChange will be assured of ongoing ... Bill Bollander , CEO states, "By ...
(Date:3/22/2016)... PROVO and SANDY, Utah ... Ontario (NSO), which operates the highest sample volume laboratory ... and Tute Genomics and UNIConnect, leaders in clinical sequencing ... announced the launch of a project to establish the ... panel. NSO has been contracted by ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016   Boston Biomedical , an ... designed to target cancer stemness pathways, announced that ... Orphan Drug Designation from the U.S. Food and ... cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin is ... inhibit cancer stemness pathways by targeting STAT3, and ...
(Date:6/23/2016)... , June 23, 2016 A person commits ... the crime scene to track the criminal down. ... U.S. Food and Drug Administration (FDA) uses DNA evidence to ... Sound far-fetched? It,s not. The FDA has ... to support investigations of foodborne illnesses. Put as simply as ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... Plate® YM (Yeast and Mold) microbial test has received AOAC Research Institute approval ... of microbial tests introduced last year,” stated Bob Salter, Vice President of Regulatory ...
(Date:6/23/2016)... , June, 23, 2016  The Biodesign Challenge ... envision new ways to harness living systems and biotechnology, ... Art (MoMA) in New York City ... 130 participating students, showcased projects at MoMA,s Celeste Bartos ... Paola Antonelli , MoMA,s senior curator of architecture and ...
Breaking Biology Technology: