In the structure of Tl < sub > 2 </ sub > Ba < sub > 2 </ sub > CuO < sub > 6 </ sub > ( Tl-2201 ), there is one CuO < sub > 2 </ sub > layer with the stacking sequence ( Tl – O ) ( Tl – O ) ( Ba – O ) ( Cu – O ) ( Ba – O ) ( Tl – O ) ( Tl – O ).

In Tl < sub > 2 </ sub > Ba < sub > 2 </ sup > CaCu < sub > 2 </ sub > O < sub > 8 </ sub > ( Tl-2212 ), there are two Cu – O layers with a Ca layer in between.

Similar to the Tl < sub > 2 </ sub > Ba < sub > 2 </ sub > CuO < sub > 6 </ sub > structure, Tl – O layers are present outside the Ba – O layers.

In Tl < sub > 2 </ sub > Ba < sub > 2 </ sub > Ca < sub > 2 </ sub > Cu < sub > 3 </ sub > O < sub > 10 </ sub > ( Tl-2223 ), there are three CuO layers enclosing Ca layers between each of these.

However, the value of T < sub > c </ sub > decreases after four CuO < sub > 2 </ sub > layers in TlBa < sub > 2 </ sub > Ca < sub > n-1 </ sub > Cu < sub > n </ sub > O < sub > 2n + 3 </ sub >, and in the Tl < sub > 2 </ sub > Ba < sub > 2 </ sub > Ca < sub > n-1 </ sub > Cu < sub > n </ sub > O < sub > 2n + 4 </ sub > compound, it decreases after three CuO < sub > 2 </ sub > layers.

Hg – Ba – Ca – Cu – O superconductor: The crystal structure of HgBa < sub > 2 </ sub > CuO < sub > 4 </ sub > ( Hg-1201 ), HgBa < sub > 2 </ sub > CaCu < sub > 2 </ sub > O < sub > 6 </ sub > ( Hg-1212 ) and HgBa < sub > 2 </ sub > Ca < sub > 2 </ sub > Cu < sub > 3 </ sub > O < sub > 8 </ sub > ( Hg-1223 ) is similar to that of Tl-1201, Tl-1212 and Tl-1223, with Hg in place of Tl.

Thallium barium calcium copper oxide ( TBCCO, Tl < sub > m </ sub > Ba < sub > 2 </ sub > Ca < sub > n − 1 </ sub > Cu < sub > n </ sub > O < sub > 2n + m + 2 + δ </ sub >) was the next class of high-T < sub > c </ sub > cuprate superconductors with T < sub > c </ sub > = 127 K observed in Tl < sub > 2 </ sub > Ba < sub > 2 </ sub > Ca < sub > 2 </ sub > Cu < sub > 3 </ sub > O < sub > 10 </ sub > ( TBCCO-2223 ) in 1988.

Ag, As, Bi, Cd, Cu, Ga, Ge, Hg, In, Pb, Po, S, Sb, Se, Sn, Te, Tl, Zn

The 80 nucleotide tRNA was sequenced by first being digested with Pancreatic ribonuclease ( producing fragments ending in Cytosine or Uridine ) and then with takadiastase ribonuclease Tl ( producing fragments which finished with Guanosine ).

The boron group is the series of elements in group 13 ( IUPAC style ) of the periodic table, comprising boron ( B ), aluminium ( Al ), gallium ( Ga ), indium ( In ), thallium ( Tl ), and ununtrium ( Uut ).

Like most radioisotopes found in the radium series, < sup > 206 </ sup > Pb was initially named as a variation of radium, specifically radium G. It is the decay product of both < sup > 210 </ sup > Po ( historically called radium F ) by alpha decay, and the much more rare < sup > 206 </ sup > Tl ( radium E < sup > II </ sup >) by beta decay.

* CsI ( Tl ) or cesium iodide doped with thallium: these crystals are one of the brightest scintillators.

< sup > 201 </ sup > Tl ( half-life 73 hrs ), decays by electron capture, emitting Hg X-rays (~ 70 – 80 keV ), and photons of 135 and 167 keV in 10 % total abundance ; therefore it has good imaging characteristics without excessive patient radiation dose.

* BGO or bismuth germanate: Bismuth germanate has a higher stopping power, but a lower optical yield than NaI ( Tl ).

It has a slightly shorter decay time than CsI ( Tl ) ( 630 ns versus 1000 ns for CsI ( Tl )).

Koski Hl was renamed Hämeenkoski in 1995 but Koski Tl has not changed its name.

) has no R-sound and is devoid of some consonant clusters like Tl, Hm ,….. in their dialects.

Thallium-doped sodium iodide ( NaI ( Tl )) has two principal advantages:

Thallium ( Tl ) has 37 isotopes which have atomic masses that range from 176 to 212.

< sup > 207 </ sup > Tl, with a half-life of 4. 77 minutes, has the longest half-life of naturally occurring radioisotopes.

Its chemical formula is reported either as Cu < sub > 7 </ sub >( Tl, Ag ) Se < sub > 4 </ sub > or ( Cu, Tl, Ag )< sub > 2 </ sub > Se.

Heavy metals ( Tl, Cd, Hg, ...) are often found as trace elements in common metal sulfides ( pyrite ( FeS < sub > 2 </ sub >), zinc blende ( ZnS ), galena ( PbS ), ...) present as secondary minerals in most of the raw materials.

They are moderately strong oxidizing agents, as illustrated by the reduction potential of + 0. 72 volts for Tl < sup > 3 +</ sup > + 3 e < sup >–</ sup > → Tl ( s ).

As an example in group 13 the + 1 oxidation state of Tl is the most stable and Tl < sup > III </ sup > compounds are comparatively rare.

< sup > 203 </ sup > Tl and < sup > 205 </ sup > Tl are the only stable isotopes, and < sup > 204 </ sup > Tl is the most stable radioisotope, with a half-life of 3. 78 years.

< sup > 208 </ sup > Tl ( half-life 3. 05 minutes ) is generated in the naturally-occurring thorium decay chain.

They are both very hygroscopic ( i. e., damaged when exposed to moisture in the air ) but offer excellent light output and energy resolution ( 63 photons / keV γ for LaBr < sub > 3 </ sub >( Ce ) versus 38 photons / keV γ for NaI ( Tl )), a fast response ( 16 ns for LaBr < sub > 3 </ sub >( Ce ) versus 230 ns for NaI ( Tl )), excellent linearity, and a very stable light output over a wide range of temperatures.

In addition LaBr < sub > 3 </ sub >( Ce ) offers a higher stopping power for γ rays ( density of 5. 08 g / cm < sup > 3 </ sup > versus 3. 67 g / cm < sup > 3 </ sup > for NaI ( Tl )).

The scintillation X-ray detector ( XC ) aboard Vela 5A and its twin Vela 5B consisted of two 1 mm thick NaI ( Tl ) crystals mounted on photomultiplier tubes and covered by a 0. 13 mm thick beryllium window.

Nisga ' a is a derivative of two Nisga ' a words-Nisk ' ( top lip ) & Tl ' ak ' ( bottom lip ), so called because the Nass River is so bountiful in food, many nations and creatures come to the river to eat.

Thin layers of CaF < sub > 2 </ sub >( Eu ) have also been used with a thicker slab of NaI ( Tl ) to make phoswiches capable of discriminating between α, β, and γ particles.

Typical numbers are ( when the incident particle is an electron ): ≈ 40 photons / keV for NaI ( Tl ), ~ 10 photons / keV for plastic scintillators, and ~ 4 photons / keV for bismuth germanate ( BGO ).

* CdWO < sub > 4 </ sub > or cadmium tungstate: a high density, high atomic number scintillator with a very long decay time ( 14 μs ), and relatively high light output ( about 1 / 3 of that of NaI ( Tl )).

Each detector had a central scintillation spectrometer crystal of NaI ( Tl ) 12 in ( 303 mm ) in diameter, by 4 in ( 102 mm ) thick, optically coupled at the rear to a 3 in ( 76. 2 mm ) thick CsI ( Na ) crystal of similar diameter, viewed by seven photomultiplier tubes, operated as a phoswich: i. e., particle and gamma-ray events from the rear produced slow-rise time (~ 1 μs ) pulses, which could be electronically distinguished from pure NaI events from the front, which produced faster (~ 0. 25 μs ) pulses.

Thallium ( ) is a chemical element with symbol Tl and atomic number 81.

The most widely used is NaI ( Tl ) ( sodium iodide doped with thallium ).

* CsI ( Na ) or cesium iodide doped with sodium: the crystal is less bright than CsI ( Tl ), but comparable in light output to NaI ( Tl ).

* LaBr < sub > 3 </ sub >( Ce ) ( or lanthanum bromide doped with cerium ): a better ( novel ) alternative to NaI ( Tl ); denser, more efficient, much faster ( having a decay time about ~ 20ns ), offers superior energy resolution due to its very high light output.

Its light output is about 1 / 3 of that of NaI ( Tl ).

Each module consisted of both a NaI ( Tl ) Large Area Detector ( LAD ) covering the 20 keV to ~ 2 MeV range, 50. 48 cm in dia by 1. 27 cm thick, and a 12. 7 cm dia by 7. 62 cm thick NaI Spectroscopy Detector, which extended the upper energy range to 8 MeV, all surrounded by a plastic scintillator in active anti-coincidence to veto the large background rates due to cosmic rays and trapped radiation.

< tr >< td > thallium ( Tl )</ td >< td > 1. 0 </ td > < td > 15 </ td >< td > 2 </ td >< td > 7 </ td ></ tr >