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 φ38x38mm Strontium Iodide SrI2(Eu) Scintillator


Next-generation Strontium Iodide Scintillator SrI2(Eu) of φ38x38mm based on the new manufacturing method named “Liquinert Process”




SrI2(Eu) scintillator has very high light yield of > 80,000 ph/MeV which is 2.2 times higher compared to a NaI(Tl) scintillator. Owing to such high light yield, energy resolution of less than 4% for 662keV 137Cs gamma-ray can be available  with1.5 inch-size of detector.

SrI2(Eu) scintillator was discovered and patented by Dr. R. Hofstadter in 1968 with poor light yield. But it was rediscovered by the team of Lawrence Livermore National Laboratory in US with high quality crystals in 2008.

Union Materials Inc. (location: Tone-machi, Ibaraki, hereinafter referred to UM) holds innovative crystal preparation technology "Liquinert"* process, and late in 2013, developed successfully high quality SrI2(Eu) crystals by using this technology.

This time, UM announced that it had established the mass production technologies to make larger sized crystals of φ38x38mm (1.5-inch cylindrical).

Use of NaI(Tl) scintillator with around 7% of energy resolution which ability for nuclide discrimination is relatively low, is common in the present market of the scintillator for radiation measurement, but of higher energy resolution is requested in nuclide discrimination.

The SrI2(Eu) scintillator has very high energy resolution (less than 4%), very high light yield, no intrinsic radioactivity, low noises and superior proportionality of the sensitivity. Therefore, it is expected with the next-generation product which can support from low energy X-ray to high energy gamma-ray.

Ampere Inc. is appointed for the exclusive distributorship of UM scintillator products.

Gamma-ray detectors are used in many fields such as environmental, medical, nuclear power plants and mining applications. The improved performances of SrI2(Eu) scintillator will answer to these various demands.


Technical Data of UM SrI2(Eu)


Energy spectra from the contaminated soil of Fukushima 

φ25x25 SrI2(Eu) of UM scintillator+R6231 PMT


A peak of 662 keV is much more clear and sharp than NaI(TI).


Superior characteristics of SrI2(Eu)

1.Energy Resolution: <4% ... Nuclide discrimination is possible.
2.Light Yield: More than 80,000 Photon/MeV
3.Intrinsic Radioactivity: No. .. Very Small Background Noises
4.Light Yield Proportionality: Broadband exact measurement is possible.
5.Larger Size Available: φ38×38

SrI2(Eu) Performances Compared to NaI(Tl)


About Union Materials, Inc.


The company was established in 1986. The head office is in Tone-machi, Ibaraki.

Union material President Sakuragi (doctor of science) studied the metallic halide crystal in The Institute for Solid State Physics, The Univ. of Tokyo from 1966.

After the establishment of the company, he brushed up his experience to an ultimate crystal growth technology named the “liquinert”  process, while studying   halides compounds, BiSbTe, Ge, GaAs and Si. The development of SrI2(Eu) single crystals was completed by the accumulation of such techniques.

And then, UM has established the production facility for the larger sized crystal of 1.5 inches recently.


What is the “Liquinert” Process of UM ?


“Liquinert” ---Liquid is inert state.


The “Liquinert” process is an ideal Bridgman technology to prepare high quality inorganic crystals in the environment where the crucible and the melt is non-wetting relation each other. This process is realized by the purification technology of raw materials, crucible and atmosphere.


Water repellency represents

the sphere shape of water on a plant leaf

at around room temperature. 

Liqinert is non-wetting and

non-reactive state of molten inorganic

materials at each melting temperature.

leaf.jpg Example.jpg

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Contact us


   Sales Contact: Tomobe Office, Industrial Products Division, Ampere Inc.

   Phone: +81-29-677-6188

   Fax.: +81-29-670-5011

   E-mail: hp_que_scintillator@ampere.co.jp

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