- Transmission Crystal Spectrometers
Artep Inc. is a leading provider of hard x-ray transmission crystal spectrometers. The Artep manufactured spectrometers are currently in use at the Lawrence Livermore National Laboratory (LLNL), the Laboratory of Laser Energetics (LLE) in Rochester, New York, Los Alamos National Laboratory in New Mexico, the Sandia Labortory in Albuquerque, New Mexico, the Laboratoire Pour l’Utilisation Des Laser Intenses (LULI) in Paris, France, the CEntre Lasers Intenses et Applications (CELIA) in Bordeaux, France and KLA Tencor in Milpitas, California.
The transmission-crystal spectrometers are of the Cauchois (Cauchois 1932 translation) type with innovative Artep improvements giving enhanced spectral resolution, spatial resolution, and shielding against hostile radiation, particle, and electromagnetic environments. The designs are based on an earlier design of bent transmission crystal spectrometers by an NRL/NIST team headed by Drs. John Seely and Lawrence Hudson.
Each of the provided spectrometers is custom designed for the specific scientific requirements and the environment in which they are meant to be operated. As such, each spectrometer project is unique and undergoes the following steps: i) a conceptual design, ii) a performance assessment of the proposed design, iii) full mechanical CAD design of the spectrometer components, iv) fabrication, quality assurance testing and assembly, v) alignment using an x-ray source, vi) x-ray performance verification testing, and vii) if required absolute calibration of spectrometer throughput and sensitivity. On average, a spectrometer project takes three to four months from start to end.
Each of the several Artep senior physicists and engineers working on these projects has well over 30 years of experience with this type of research and development at DOE and DOD national laboratories as well as in the private sector.
Examples of parameters incorporated into spectrometers constructed in recent years are listed below:
|Energy range:||6-260 keV|
|Standoff distances:||254mm to 6000 mm|
|Rowland circle diameter:||118 mm, 254 mm and 330mm|
|Crystal detector distances:||118 mm to 850 mm|
|Transmission Crystal used:||Quarts (100) 2d-0.8152 nm, Quartz (101) 2d=0.6687 nm,
Quartz (203) 2d=0.2749 nm and Quartz (502) 2d=0.1624 nm
2. Elliptical bent reflection crystal
Artep has the experience of producing crystals packs consisting of crystals mounted on spherical and elliptical shaped holders. The crystals are mechanically attached and not glued to the holders.
3. Calibration facility
Artep has the experience in the custom design and construction of turnkey vacuum facilities for the absolute calibration in the keV energy range of crystals in transmission and reflection, image plates, electronic detectors and end to end spectrometers. Such a facility may include a large vacuum tank, x ray source capable of housing 10 different anodes, electron gun, absolutely calibrated detector.
A recently constructed calibration facility includes a vacuum chamber (2.0 m x 0.5 m x 0.3 m) evacuated by a large turbo and fore pumps. A moveable structure placed within the chamber is designed to support devices to be calibrated, an absolutely and remotely computer controlled electronic detector, x-z remotely controlled servo mechanism for moving the detector, and a laser based aligning system. The x ray source connected to the chamber via a gate valve consists of 10 preselected anodes. The selected anode can be moved into position without breaking the vacuum. An electron beam with maximum voltage of 30 keV which could be focused to a spot of ~1 mm drives the x ray source.
Additional information and references will be provided upon request