Patent GB-1348427-A (GB)
Title: Scintillators
IPC: C09K11/06
Filed: 1971-07-26
Abstract: 1348427 Tri-aryl boranes EASTMAN KODAK CO 26 July 1971 [27 July 1970] 34940/71 Heading C2B [Also in Division C4] A scintillator solution comprises an energy transfer solvent containing as fluorescent solute a triarylborane of formula in which x is an integer 1 to 3, R<SP>1</SP>, R<SP>2</SP>, R<SP>4</SP>, R<SP>5</SP>, R<SP>6</SP>, R<SP>7</SP>, R<SP>9</SP>, R<SP>10</SP>, R<SP>11</SP>, R<SP>12</SP>, R<SP>14</SP> and R<SP>15</SP> are the same or different and represent a H atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted phenyl group or an electron donating group, or R<SP>1</SP> and R<SP>2</SP>, R<SP>4</SP> and R<SP>5</SP>, R<SP>6</SP> and R<SP>7</SP>, R<SP>9</SP> and R<SP>10</SP> ,  R<SP>11</SP> and R<SP>12</SP> ,  R<SP>12</SP> and R<SP>13</SP> ,  R<SP>13</SP> and R<SP>14</SP> or R<SP>14</SP> and R<SP>15</SP> when taken together, represent the atoms necessary to complete a fused aromatic ring system; R<SP>3</SP> and R<SP>8</SP> each represent a hydrogen atom, a halogen atom, a cyano group, a carboxy group, an optionally substituted alkyl group or an electron donating group; R<SP>3</SP> taken alone, when x = 1, represents one of the groups R<SP>3</SP> and R<SP>8</SP>, or when x = 2, a covalent bond, an alkimino group, a cycloalkylimino group or a vinylene group or when x represents 3, the group -N-; provided that at least four of the groups R<SP>1</SP>, R<SP>5</SP>, R<SP>6</SP>, R<SP>10</SP>, R<SP>11</SP> and R<SP>15</SP> are other than hydrogen and at least one of R<SP>1</SP>, R<SP>3</SP> ,  R<SP>5</SP>, R<SP>6</SP>, R<SP>8</SP> ,  R<SP>10</SP>, R<SP>11</SP>, R<SP>13</SP> and R<SP>15</SP> is an electron donating group when none of the pairs of groups R<SP>11</SP> and R<SP>12</SP>, R<SP>12</SP> and R<SP>13</SP>, R<SP>13</SP> and R<SP>14</SP>, R<SP>14</SP> and R<SP>15</SP> are taken together to form a fused aromatic ring system. Many examples are disclosed including stilbenes, amines and anthracenes with a B atom bonded directly to 3 aryl groups. Input radiation may be X-, γ-rays, electrons, neutrons, positrons, protons, deuterons, tritons, α-particles, fission fragments, Á mesons or # mesons. The term " electron donating group " is defined as one of the groups: hydroxy, optionally substituted alkoxy, aryloxy, amino including substituted amino, alkylazo, arylazo, or an unsaturated aliphatic group or aryl substituted unsaturated aliphatic group in which the unsaturation is conjugated with the aryl group to which the electron donating group is attached. Scintillation counters may incorporate photomultipliers (e.g. p/c, dynodes, anode) and pulse recorders (e.g. output capacitor with linear pulse recorder) and different measurements are instanced. The solvent may be a mixed solvent and have an abundance of #-electrons, e.g. xylene and toluene. The energy transfer solvent may fluoresce at 250 to 350 nm and the primary scintillator absorb at 250 to 350 nm, e.g. 288 nm with dioxane-naphthalene system, emitting 350 to 400 nm, a wavelength shifter then emitting at 350 to 400 nm. The solute may be 2,2<SP>1</SP>-p-phenylenebis-(5-phenyloxazole). Detailed preparations are described. Starting materials include Grignard reagents, ArMgX, and aryllithium compounds, ArLi, for example. Primary scintillators which may be used with the triarylboranes when secondary scintillators, include 2,5-diphenyloxazole, terphenyl, 2-phenyl-5-(4- biphenylyl) - 1,3,4 - oxadiazole, 2 - (4 - t - butylphenyl) - 5 - (4 - biphenylyl) - 1,3,4 - oxadiazole, 2 - (1 - naphthyl) - 5 - phenyloxazole and 2,5- di - (4 - biphenylyl)oxazole, 1,1 - dinaphthyl. In detecting neutrons, the boranes undergo the reaction B<SP>10</SP>(n, α)Li<SP>7</SP> or may incorporate additional neutron captive solutes, e.g. B compounds e.g. alkyl borates, trimethyl borate, boron trifluoride and triborine triamine, or those reacting as Li<SP>6</SP>(n, α)H<SP>3</SP>. Solvents include transparent hydrocarbons, ethers and mixed solvents and aromatic solvents, e.g. benzene, alkyl benzenes, e.g. xylene, toluene, phenylcyclohexane, ethylbenzene, triethylbenze, butyl benzene and cumene; aromatic ethers, e.g. anisole; and mixed solvents such as naphthalene-p-dioxane, toluene-methanol and toluene-ethanol. Particular mixture combinations and concentrations are given. Gamma captive solutes, suspending and modifying agents may also be included. A '' cocktail'' may include the material to be tested, e.g. #-emitter such as tritium or C<SP>14</SP> labelled organic compound (e.g. benzoic acid) or α-, γ-, X-ray, meson and neutron emitters. Water may be a constituent.