Glossary |
Glossary of Terms used on this website.
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| ALS | Advanced Light Source Synchrotron User Facility |
| beamtime | Beamtime is the operating time when there is synchrotron beam available in a specific beamline. Beamtime is allocated in shifts of 8 hours each, and can be scheduled on the IR beamlines in increments of 0.5 shifts (4 hours). One user is scheduled at a time for each beamline whenever beamtime is available. |
| bending magnet | A bending magnet changes the path of the electrons in the storage ring. This acceleration causes synchrotron radiation to be emitted. The light used by the infrared beamlines are all from bending magnet sources. |
| brightness | Flux per unit area. It is by a factor of ~1000 that synchrotron IR sources are brighter than conventional thermal IR sources. |
| brilliance | See brightness.
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| Continuum | The infrared microscope on Beamline 1.4.4 is a Thermo Scientific Continuum XL. |
| cryostat | A cryostat is used to cool a sample to below room temperature, and typically to cryogenic temperatures such as liquid nitrogen (77K), liquid helium (4.2k), or even lower. The infrared beamlines have several cryostats available to users. |
| cycle | The ALS runs in beamtime cycles, typically 6 months long, and typically January - June, and July - December of each calendar year. Users must apply for beamtime for each cycle, or renew an active beamtime proposal for the next cycle. |
| DLATGS | deuterated lanthanum triglycine sulfate - room temperature mid-infrared detector often used in FTIR benches. |
| DOE | U.S. Department of Energy (the major funder of LBNL and ALS activities). |
| DTGS | Deuterated triglycine sulfate - type of room-temperature infrared detector commonly used in FTIR benches. |
| far-IR | Far-infrared region, approximately 5 - 500 cm-1. Also called Terahertz radiation. Has traditionally been used for rotational spectroscopy, but the emerging field has many new applications in communications, security, and imaging. |
| front end | The first part of a synchrotron beamine, usually the part that is behind the shield wall and connects directly to the storage ring, is called the front end. |
| FTIR | Fourier Transform Infra-Red |
| InSB | Indium antimonide - often used as element for a near infrared detector. Can also be used as an element for hot electron bolometer for the far-IR region, primarily in the 1-10 cm-1 range. |
| IR | Infra-Red, or simply infrared. |
| LBNL | (Earnest Orlando) Lawrence Berkeley National Laboratory |
| LN2 | Liquid Nitrogen. This cryogen is used for cooling MCT detectors to 77 Kelvin. |
| MCT | Mercury cadmium telluride (HgCdTe) - HgCdTe is a ternary semiconductor compound which exhibits a wavelength cutoff proportional to the alloy composition. This type of detector is used in our infrared microscopes and requires liquid nitrogen cooling. |
| mid-IR | mid-infrared region, approximately 500 - 4000 cm-1. Can be used to study the vibrations of most molecules. Because every molecule has a unique infrared spectrum, mid-IR spectroscopy has become a workhorse for analytical, biological, environmental, forensic, and material science applications. |
| NA | numerical aperture, n*sin(theta) |
| near-IR | Near-infrared, approximately 4000 - 14000 cm-1. Covers the region of overtone vibrations and has many applications, including biological and medical imaging |
| Nic-Plan | The infrared microscope on Beamline 1.4.3 is a Nic-Plan microscope. |
| shield wall | The synchrotron storage ring is located behind a shield wall, a large cement, steel and lead wall designed to protect all people from any radiation that could be generated by the accelerator. The beamlines come out through special ports in the shield wall. Access behind the shield wall is not permitted during normal operations, only on maintenance days. |
| storage ring | A storage ring is a primary component of a synchrotron used to store the high-energy electrons as they circulate emitting synchrotron radiation. |
| synchrotron | An electron accelerator used to produce light called synchrotron radiation. Most synchrotrons are designed to produce x-rays, but they also produce light with energies all the way down through the UV, visible and infrared. |
| synchrotron radiation | Synchrotron radiation is the light emitted by a relativistic charged particle when accelerated. The light from a synchrotron is called synchrotron radiation. |
| THz | Terahertz, see far-IR. |
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Glossary of Terms
