گارنت اللوتتيوم ألومنيوم
گارنت اللوتتيوم ألومنيوم (Lutetium aluminium garnet وتشيع الإشارة إليه بالرمز LuAG، صيغته الجزيئية Al5Lu3O12) هي مركب غير عضوي ذو بنية بلورية فريدة، وتُعرف أساساً لاستخدامها في أجهزة الليزر عالية الكفاءة. كما أنها مفيدة في تخليق سيراميك شفاف اُقترح إستخدامها لصناعة العدسات وذلك لأنها ذات معامل إنكسار عالي..[1]
وعندما تغمس في السيريوم فإنها تكتسب وميضاً scintillation مع تألق واضح، مما يؤهلها للاستخدام في اكتشاف الفوتونات عالية الطاقة.[2]
LuAG is a dopable scintillating crystal that will demonstrate luminescence after excitation. Scintillating crystals are selected for high structural perfection, high density and high effective atomic number. LuAG is particularly favored over other crystals for its high density and thermal conductivity. LuAG has a relatively small lattice constant in comparison to the other rare-earth garnets, which results in a higher density producing a crystal field with narrower linewidths and greater energy level splitting in absorption and emission.[3] These properties make it an excellent host for active ions such as Yb, Tm, Er, and Ho employed in diode-pumped solid-state lasers. The density of the lutetium crystal is greater than that of other metals, such as yttrium, meaning that the crystal properties do not change with the addition of dopant ions.[4] It can be especially useful for high energy particle detection and quantification on account of its density and thermal stability. This high melting temperature, in addition to the lack of availability of lutetium has made this crystal less commonly used than its fellow garnets, despite its favorable physical properties.[1]
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الخصائص الطبيعية والبـُنية
Lutetium aluminum garnet, with the molecular formula Al5Lu3O12, has a complex cubic crystal structure. The unit cell contains 24 lutetium atoms in c sites, 96 oxygen atoms in h sites, and aluminum in 16 a sites and 24 d sites.[5]
The mass of the lutetium ion is closer to laser-active lanthanides which are used for doping, meaning that the thermal conductivity is not altered as it would be in other garnet structures at higher doping levels. Additionally, the crystal radius of lutetium limits the alterations observed in the crystal structure with doping present.[1]
| الصيغة الكيميائية | Al5Lu3O12 |
|---|---|
| البنية البلورية | Cubic |
| الوزن الجزيئي | 851.81 g/mol |
| الكثافة | 6.71 g/cm^3 |
| نفطة الانصهار | 1980 ˚C |
| الحرارة النوعية | 0.419 J/gK |
انظر أيضاً
المراجع
- ^ أ ب ت Moore, Cheryl (2015). "Towards a Greater Understanding of Hydrothermally Grown Garnets and Sesquioxide Crystals for Laser Applications". Clemson University Tiger Prints. Bibcode:2015PhDT.......308M.
- ^ Transparent Ceramic Lutetium Aluminium Garnet Scintillators (ملخص)
- ^ أ ب "Lutetium Aluminum Garnet - LuAG - Lu3Al5O12". scientificmaterials.com. Retrieved 2016-04-29.
- ^ Kiss, Z. J.; Pressley, R. J. (1966-10-01). "Crystalline Solid Lasers". Applied Optics (in الإنجليزية). 5 (10): 1474–86. Bibcode:1966ApOpt...5.1474K. doi:10.1364/ao.5.001474. ISSN 1539-4522. PMID 20057583.
- ^ Kuwano, Yasuhiko; Suda, Katsumi; Ishizawa, Nobuo; Yamada, Toyoaki (2004-01-02). "Crystal growth and properties of (Lu,Y)3Al5O12". Journal of Crystal Growth. 260 (1–2): 159–165. Bibcode:2004JCrGr.260..159K. doi:10.1016/j.jcrysgro.2003.08.060.