Activated alkali metal rare earth halides and articles using same
Scintillator materials based on certain types of activated alkali metal rare earth halide materials are described. In one embodiment, the material contains CsLaBr 4 with Ce(III) ions substituted for a portion of the La component. The scintillator or other detector materials can be in monocrystalline or polycrystalline form. Radiation detectors that use the scintillators are also described, as are related methods for detecting high-energy radiation.
1 . An activated alkali metal rare earth halide having the formula A[RE]X 4 :T, wherein A is an alkali metal, [RE] is a rare earth element, X is a halogen, and T is an activator element.
2 . The activated alkali metal rare earth halide of claim 1 , wherein the alkali metal comprises cesium.
3 . The activated alkali metal rare earth halide of claim 1 , wherein the rare earth element comprises yttrium, gadolinium, lanthanum, lutetium, or a combination thereof.
4 . The activated alkali metal rare earth halide of claim 3 , wherein the rare earth element comprises lanthanum.
5 . The activated alkali metal rare earth halide of claim 1 , wherein the halogen comprises bromine.
6 . The activated alkali metal rare earth halide of claim 1 , wherein the activator comprises cerium, bismuth, thallium, or a combination thereof
7 . The activated alkali metal rare earth halide of claim 1 , wherein the activator is substituted for a portion of the rare earth element and is present in a total amount from about 0.1 mol % to about 20 mol %.
8 . The activated alkali metal rare earth halide of claim 7 , wherein the activator is substituted for a portion of the rare earth element and is present in a total amount from about 1 mol % to about 10 mol %.
9 . The activated alkali metal rare earth halide of claim 6 , wherein the activator is substituted for a portion of the rare earth element and is present in a total amount from about 1 mol % to about 10 mol %.
10 . The activated alkali metal rare earth halide of claim 1 , wherein:
the alkali metal comprises cesium;
the rare earth element comprises lanthanum;
the halogen comprises bromine;
the activator comprises cerium, is present in a total amount from about 1 mol % to about 10 mol %, and is substituted for a portion of the rare earth element.
11 . The activated alkali metal rare earth halide of claim 10 , having the formula CsLa 0.95 Ce 0.05 Br 4 .
12 . A sensing element activated by radiation comprising:
a first scintillator activated by gamma-radiation; and
a neutron-sensing layer comprising a second scintillator activated by neutron radiation;
wherein the first scintillator comprises an activated alkali metal rare earth halide having the formula A[RE]X 4 :T, and wherein A is an alkali metal, [RE] is a rare earth element, X is a halogen, and T is an activator element.
13 . The sensing element of claim 12 , wherein:
the alkali metal comprises cesium;
the rare earth element comprises lanthanum;
the halogen comprises bromine;
the activator comprises cerium, is present in a total amount from about 1 mol % to about 10 mol %, and is substituted for a portion of the rare earth element.
14 . The sensing element of claim 13 , wherein the activated alkali metal rare earth halide comprises CsLa 0.95 Ce 0.05 Br 4 .
15 . The sensing element of claim 12 , wherein the second scintillator comprises ZnS(Ag)—LiF.
16 . The sensing element of claim 14 , wherein the second scintillator comprises ZnS(Ag)—LiF.
17 . A radiation detector capable of detecting both gamma-rays and neutrons comprising:
a radiation-sensing element comprising a gamma-radiation-sensing first scintillator and a neutron-sensing second scintillator; and
a photosensor;
wherein the gamma-radiation-sensing first scintillator comprises an activated alkali metal rare earth halide having the formula A[RE]X 4 :T, and wherein A is an alkali metal, [RE] is a rare earth element, X is a halogen, and T is an activator element.
18 . The radiation detector of claim 17 , wherein the second scintillator is structured not to excite the first scintillator and is also not excitable by the first scintillator.
19 . The radiation detector of claim 17 , wherein the detector is hand-held or portable.
20 . The radiation detector of claim 17 , wherein the first scintillator and the second scintillator are optically connected such that the light from one scintillator passes through the other.
21 . The radiation detector of claim 17 , wherein the first scintillator and the second scintillator are optically separated.
22 . The radiation detector of claim 17 , further comprising a photodiode for both reading the second scintillator and for direct detection of low-energy gamma-rays, wherein the detector is structured with pulse-shape discrimination capability to discriminate between low-energy gamma-rays and neutrons.
23 . The radiation detector of claim 17 , further comprising a moderating material to thermalize neutrons before detection in order to increase detection efficiency.
24 . The radiation detector of claim 17 , wherein:
the alkali metal comprises cesium;
the rare earth element comprises lanthanum;
the halogen comprises bromine;
the activator comprises cerium, is present in a total amount from about 1 mol % to about 10 mol %, and is substituted for a portion of the rare earth element.
25 . The radiation detector of claim 24 , wherein the activated alkali metal rare earth halide comprises CsLa 0.95 Ce 0.05 Br 4 .
26 . The radiation detector of claim 17 , wherein the second scintillator comprises ZnS(Ag)—LiF.
27 . The radiation detector of claim 25 , wherein the second scintillator comprises ZnS(Ag)—LiF.
28 . The radiation detector of claim 17 , wherein:
the second scintillator is structured not to excite the first scintillator and is also not excitable by the first scintillator;
the detector is hand-held or portable;
the detector further comprises a photodiode for both reading the second scintillator and for direct detection of low-energy gamma-rays, wherein the detector is structured with pulse-shape discrimination capability to discriminate between low-energy gamma-rays and neutrons;
the detector further comprises a moderating material to thermalize neutrons before detection in order to increase detection efficiency;
the activated alkali metal rare earth halide comprises CsLa 0.95 Ce 0.05 Br 4 ; and
the second scintillator comprises ZnS(Ag)—LiF.