Custom Scintillation Detectors

 

 

 

 

 

 

 

 

Berkeley Nucleonics offers a comprehensive range of standard, specialized, and custom built scintillation detectors designed to meet the most stringent radiation counting applications. All known scintillation materials are employed ranging from plastics to liquid scintillators to inorganic crystals such as NaI(Tl), CsI(Tl)(Na), high-density BGO, high-resolution CeBr3, plus many more. The characteristics of the more frequently employed scintillators can be found below. 

 

A great number of possibilities exist when considering the properties of a detector design. Whether detecting particles or electromagnetic radiation such as gamma or x-rays, a determination on the type of scintillation material, its size, and readout method must be made. Additionally, the use of integrated or plug-on electronics such as a voltage divider or preamplifier must be considered. In practice, many scintillation detectors are often "tailor made" to meet the customer's specific application. 

 

Please contact us directly or complete our brief Detector Survey to have your requirements reviewed by an engineer. 

See our Scintillator Line Card below

Sodium Iodide Detectors

NaI(Tl) scintillation crystals are used in most standard applications for detection of Gamma radiation because of their unequaled high light output and the excellent match of the emission spectrum to the sensitivity of photomultiplier tubes, resulting in a good energy resolution.

Physical Properties:

Density
-
3.67 g/cm3
Emission Max
-
415 nm
Decay Constant
-
0.23 µs
Refractive index
-
1.85
Conversion Effency
-
100
Hygroscopic
-
Yes

Cesium Iodide Detectors (Tl)(Na)(undoped)

CsI(Tl) has the advantage that it is non-hygroscopic, does not cleave and can be read out using silicon photodiodes instead of photomultiplier tubes. These so-called Scintillator Photodiode Detectors are compact, very stable, do not require any high voltage, are rugged, and can be operated in high magnetic fields. These detectors are frequently used in arrays or matrices in particle physics research. Physical Properties:

Density
-
4.51 g/cm3
Emission Max
-
550 nm
Decay Constant
-
0.6/3.4 µs
Refractive index
-
1.79
Conversion Effency
-
45
Hygroscopic
-
No

CsI(Na) is a non-hygroscopic, high light output scintillator mainly used for applications where mechanical stability and good energy resolution are required. Below 120 o C it is an alternative to NaI(Tl). Physical Properties:

Density
-
4.51 g/cm3
Emission Max
-
420 nm
Decay Constant
-
0.63 µs
Refractive index
-
1.84
Conversion Effency
-
85
Hygroscopic
-
Slightly

CsI(Undoped) Fast, non-hygroscopic, radiation hard, low light output. Applications - Physics (calorimetry).

Physical Properties:

Density
-
4.51 g/cm3
Emission Max
-
315 nm
Decay Constant
-
16 ns
Refractive index
-
1.47
Conversion Effency
-
4-6
Hygroscopic
-
No

BGO Detectors

BGO has the extreme high density of 7.13 g /cm 3 and has a high Z value which makes these crystals very suited for the detection of natural radioactivity (U, Th, K), for high energy physics applications (high photofraction) or in compact Compton suppression spectrometers.

Physical Properties:

Density
-
7.13 g/cm3
Emission Max
-
480 nm
Decay Constant
-
0.3 µs
Refractive index
-
2.15
Conversion Effency
-
15-20
Hygroscopic
-
No

CaF2 Detectors

CaF 2 (Eu), Europium doped calcium fluoride is a low density scintillation crystal with a high light output. Thanks to its low Z value it is well suited for the detection of electrons (beta particles) with a high efficiency (low backscatter fraction). CaF 2 (Eu) is a crystal that is also used in phoswich scintillation detectors in combination with NaI(Tl).

Physical Properties:

Density
-
3.18 g/cm3
Emission Max
-
435 nm
Decay Constant
-
0.84 µs
Refractive index
-
1.47
Conversion Effency
-
50
Hygroscopic
-
No

6Lil(Eu) Detectors

High neutron cross-section, high light output. Applications - Thermal neutron detection and spectroscopy.

  • 3 mm LiI(Eu) stops 90% of thermal neutrons
  • Rugged crystal (> 20 degrees C gradient / hour allowed)
  • Excellent neutron / Gamma discrimination (neutron peak > 3 MeV)
  • Neutron peak resolution < 7% FWHM (PMT readout)

Physical Properties:

Density
-
4.1 g/cm3
Effective decay time
-
1.4 s
High Neutron Peak Position
-
> 3 MeV
Photoelectron yield
-
30-35 % of NaI(tl)
6-Li enrichment
-
96%

Neutron Detection

Neutrons do not produce ionization directly in scintillation crystals, but can be detected through their interaction with the nuclei of a suitable element. In a 6 LiI(Eu) scintillation crystal for example, neutrons interact with 6 Li nuclei to produce an alpha particle and a triton (tritium nucleus), which both produce scintillation light that can be detected. For this purpose, also enriched 6 Li containing glasses can be used, doped with Ce as activator.

6Li - Glass Detectors Glass scintillator with enriched Li-6 content of 96%.
Applications - Thermal neutron detection.
Physical Properties:

 

 

Composition
-
SiO2, MgO, Al2O3, Ce2O3, 6-Li2O (18 %)
Li-6 content by weight
-
7.9 %
Density
-
2.5 - 2.7 g / cm3
Primary decay time
-
60 ns
Thermal Neutron peak loc
-
1.7 – 1.9 MeV
Photoelectron yield
-
30-35 % of NaI(tl)4 - 6 %
relative to NaI(Tl) for Gamma rays

 

 

CdWO4

This material has a very high density, low afterglow and is radiation hard.

Applications - low afterglow CT applications, DC measurement of X-rays (high intensity), readout with photodiodes, Computerized Tomography (CT).
Physical Properties:

Density
-
7.9
Emission Max
-
470 / 540 nm
Decay Constant
-
20 / 5 µs
Refractive index
-
2.3
Conversion Effency
-
25-30
Hygroscopic
-
no

CeBr3

CeBr3 offers an alternative to NaI(Tl) crystals for high resolution gamma spectrometry. Above an energy of 200 keV, the resolution is superior to NaI(Tl). CeBr3 scintillation detectors do not suffer from the intrinsic La-138 background typical for Lahalide scintillators. Physical Properties:

 

Density
-
5.23 g/cm3
Emission Max
-
370 nm
Decay Constant
-
16 ns
Refractive index
-
1.9
Conversion Effency
-
130
Hygroscopic
-
Yes

 

YAP:Ce

YAP:Ce is a high density (5.5 g/cm 3) oxide crystal with a decay time about 10 times shorter than NaI(Tl). It is used in detectors for high count rate (up to several MHz) X-ray spectrometry. The non-hygroscopic nature of this material allows the use of thin mylar entrance windows and guarantees a long lifetime of the detector. Physical Properties:

Density
-
5.55 g/cm3
Emission Max
-
350 nm
Decay Constant
-
27 µs
Refractive index
-
1.94
Conversion Effency
-
35-40
Hygroscopic
-
No

Plastic Detectors

Organic (plastic) scintillators consist of a transparent host material (a plastic) doped with a scintillating organic molecule (e.g. POPOP : p-bis [2-(5-phenyloxazolyl)] benzene). Radiation is absorbed by the host material, mostly via Compton effect because of the low density and Z- value of organic materials. Therefore, plastic scintillators are mostly used for the detection of b - and other particles. Furthermore plastic scintillators are mainly used when large detector volumes are required e.g. in security or health physics applications. The cost of large plastic scintillation detectors (per volume) is much lower than that of equivalent size NaI(Tl) detectors; plastic scintillators can be manufactured in meter long slabs.

Physical Properties:

Density
-
1.03 g/cm3
Emission Max
-
375-600 nm
Decay Constant
-
1-3 µs
Refractive index
-
1.58
Conversion Effency
-
25-30
Hygroscopic
-
No