Specifična konstanta apsorpcije

Specifična konstanta apsorpcije (engl. Specific absorption rate, SAR) je mera količine energije koju apsorbuje telo kada je izloženo radio zračenju elektromagnetnog polja. Ona se takođe može odnositi na apsorpciju drugih formi energije od strane tkiva, kao što je ultrazvuk.^[1] SAR je definisan kao snaga apsorbovana po masi tkiva i ima jedinicu Vat po kilogramu.^[2]

SAR je uobičajno usredsrednjen preko celog tela, ili preko malog eksperimentalnog uzorka (od 1 g do 10 g tkiva).

Izračunavanje

SAR se može izračunati iz električnog polja unutar tkiva, koristeći sledeći obrazac:

{\text{SAR}}=\int _{\textrm {sample}}{\frac {\sigma (\mathbf {r} )|\mathbf {E} (\mathbf {r} )|^{2}}{\rho (\mathbf {r} )}}d\mathbf {r}

gde je:

\sigma

je električna provodnost uzorka

E

je RMS električnog plja

\rho

je gustina uzorka

Reference

↑ „Focusing of therapeutic ultrasound through a human skull: A numerical study”. ^{[mrtav link]}
↑ Jianming Jin (1998). Electromagnetic Analysis and Design in Magnetic Resonance Imaging. CRC Press. str. §5.3.3 pp. 226ff. ISBN 978-0849396939.

Vanjske veze

Specific Absorption Rate (SAR) for Cellular Telephones at the US Federal Communications Commission (FCC)
- "Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Field" (Supplement C to OET Bulletin 65), June 2001; a detailed technical document about measuring SAR
Electromagnetic fields and public health at the World Health Organization (WHO)
"An Update on SAR Standards and the Basic Requirements for SAR Assessment" Arhivirano 2017-08-30 na Wayback Machine-u at ETS-Lindgren website, April 2005
Example of a detailed SAR report from the FCC web site (for an Apple iPod Touch 4th generation); hosted at 3rd party website

[1] „Focusing of therapeutic ultrasound through a human skull: A numerical study”. ^{[mrtav link]}

[2] Jianming Jin (1998). Electromagnetic Analysis and Design in Magnetic Resonance Imaging. CRC Press. str. §5.3.3 pp. 226ff. ISBN 978-0849396939.

[1]

[2]