Assembly Materials

An assortment of materials for an optical interface, wrapping and reflector materials are available for assembling your own detector.

Optical, Paint, Tape, Resin

  • Optical Grease
    • BC-631 Silicone Optical Grease temporarily out of stock
  • Optical Pads
    • BC-634A Optical Interface Pad
    • BC-637 High-temperature Optical Interface Pad
  • Reflector Paint
    • BC-621 Reflector Paint for Plastic Scintillators
    • BC-622A Reflector Paint for Liquid Scintillators
  • Tapes
    • BC-638 Black Wrapping Tape
    • BC-640 Plastic Masking Tape
    • BC-642 PTFE Reflector Tape
  • Casting Resin
    • BC-490 Plastic Scintillator Casting Resin
  • Beta Paint
    • BC-498 Scintillator Paint for Beta Detection
Optical Pads

BC-634A is a silicone-adhesive coupling compound for making an optically clear bond between the scintillator and photomultiplier tube. BC-634A is formulated for use within the temperature range of -10 to +60oC, has an index of refraction of 1.42 and an internal transmission >98% around 400nm.  BC-634A is a self-wetting, flexible pad just hard enough to resist tearing while handling. 

Note: If you cannot maintain sufficient interface pressure, apply a thin film of coupling grease to both sides of the interface pad. 

BC-637 interface pads are a silicone-adhesive coupling compound for making an optically clear bond between the scintillator and photomultiplier tube. BC-637 is rated to 200oC.

We supply as ready-to-use disks in specified diameters and in thicknesses of 1, 3 and 6 mm.

Diameter inches (mm) Thickness inches (mm) Part number
1” (25.4mm) 0.039 (1mm) 6634A-00047
1” (25.4mm) 0.118 (3mm) 6634A-00041
1" (25.4mm) 0.236 (6mm) 6634A-00165
1.5” (38.1mm) 0.039 (1mm) 6634A-00068
1.5” (38.1mm) 0.118 (3mm) 6634A-00057
1.5” (38.1mm) 0.236 (6mm) 6634A-00194
2” (50.8mm) 0.039 (1mm) 6634A-00046
2” (50.8mm) 0.118 (3mm) 6634A-00056
2” (50.8mm) 0.236 (6mm) 6634A-00096
3” (76.2mm) 0.039 (1mm) 6634A-00021
3” (76.2mm) 0.118 (3mm) 6634A-00042
3” (76.2mm) 0.236 (6mm) 6634A-00166
1” (25.4mm) 0.039 (1mm) 6637-00003
1” (25.4mm) 0.118 (3mm) 6637-00031
1” (25.4mm) 0.236 (6mm)  
1.5” (38.1mm) 0.039 (1mm) 6637-00054
1.5” (38.1mm) 0.118 (3mm) 6637-00056
1.5” (38.1mm) 0.236 (6mm)  
2” (50.8mm) 0.039 (1mm) 6637-00004
2” (50.8mm) 0.118 (3mm) 6637-00010
2” (50.8mm) 0.236 (6mm)  
3” (76.2mm) 0.039 (1mm) 6637-00075
3” (76.2mm) 0.118 (3mm) 6637-00024
3” (76.2mm) 0.236 (6mm)  
Typical Thickness Tolerance: +/-0.25 mm (+/-0.0098") / Typical Diameter Tolerance: +/- 1 mm (+/-0.039")




Reflector Paint

BC-621 is a highly efficient reflector employing a special grade of titanium dioxide in a water-soluble binder. It is applied directly onto plastic scintillators, acrylic light guides, glass and metals. It is not intended for direct contact with liquid scintillators (use BC-622A for that application). It is a diffuse reflector, and, therefore, should not be applied to sheets of scintillator or light guide material where the length is much longer than the thickness.

BC-621 provides an excellent combination of high reflectivity, excellent resistance to yellowing with age, good adhesion, and ease of application. It is recommended for all scintillators having emission spectra above 415nm.

1-liter Ordering Part number: 6621-1000
2.5 liters Ordering Part number: 6621-2500

BC-621 reflectivity


BC-621 should be stirred or shaken well before using. It may be applied by brushing or spraying and may be diluted with water as required. Equipment may be cleaned with cold or warm water and detergent. When the reflector is dried, it is not affected by moisture. Two to three coats are recommended. Allow each coat to dry at room temperature before applying another layer. 300ml covers approximately a square meter with one sprayed coat.  


BC-622A reflector paint made from cross-linked polyurethane resin with exceptional chemical resistance to aromatics hence best-suited for use with liquid scintillators. It is particularly useful in large, steel or aluminum tanks, which require the application of the paint at the research site.

500 ml Ordering Part number: 622A-00001
1-liter Ordering Part number: 622A-00002


Thoroughly clean and degrease the surfaces to be painted. Roughen with abrasive paper, if possible. Mix only enough paint and hardener for one coat (approximately 350 ml of mix per square meter). Stir the white paint well before removing from the original can and thoroughly mix the two components in the following proportions:
Paint 2 parts by volume
Hardener 1 part by volume

The mixture has a pot life of about two hours at room temperature. Quantities of 25 ml or more will have a shorter pot life if allowed to remain in one compact mass owing to the heat generated by the exothermic reaction. Apply with a brush and let it partially cure (about one hour) then apply the next coat. Three coats are usually required. Curing times are 4 hours at 20ºC or 1 hour at 50ºC. Do not exceed 55ºC. For cleaning brushes, use methylene-chloride (dichloromethane) or chloroform (trichloromethane).

BC-622A gives off flammable vapor and should not be used near open flames. Skin contact should be avoided. The painting should be done in a ventilated area.

BC-638 is a black adhesive tape 2" (50.8mm) wide by .008" (0.2mm) thick. Wrapping a plastic scintillator in one layer will give you a light-tight seal.

Size: 2" wide X 32.9m long Ordering Part number: S-1033-1

BC-640 is an adhesive-backed masking paper routinely used for protecting the surfaces of plastic scintillators during handling or storage.

Size: 12” (30.5cm) wide by 300' (91.4m) Ordering Part number: 6640-00002

BC-642 Teflon® tape is frequently used as a reflecting material for non-hygroscopic scintillators. Three layers give you optimum reflectivity.

2" wide X 13.7m long on 3" PTFE core .003" (0.08 mm) thick (normal) Ordering Part number: S-1006-7

Casting Resin

BC-490 is a partially polymerized plastic scintillator that is cured to full hardness by the end-user. The scintillator thus formed is clear with scintillation and mechanical properties similar to those of SGC’s general-purpose plastic scintillators. It is most frequently used in applications that require other materials to be embedded in the scintillator, and which require the casting of unique shapes (often in special holders).

BC-490 is supplied in complete kits with detailed instructions. Each kit contains three parts: partially polymerized scintillator resin, catalyst, and catalyst solvent.

500 ml Ordering Part number: 6490-00002
1-liter Ordering Part number: 6490-00001

Scintillation Properties of Hardened BC-490
Light Output, %Anthracene 55
Decay Time (ns) -2.3
Wavelength of Max. Emission, nm 425
Atomic Composition
No. of H Atoms per cc (x1022) 5.23
No. of C Atoms per cc (x1022) 4.73
Ratio H:C Atoms 1.1
No. of Electrons per cc (x1023) 3.37
General Technical Data
Base Polyvinyltoluene
Density [g/cc] 1.032
Expansion Coefficient (perºC,<67ºC) ~7.8X10-5
Refractive index 1.58
Softening Point 70°C
Vapor Pressure May be used in a vacuum
Solubility Soluble in aromatic solvents, chlorinated solvents, acetone, etc. Unaffected by water, dilute acids, lower alcohols, alkalis and pure silicone fluids or grease.
Light Output At +60oC = 95% of that at+20oC. Independent of temperature from -60oC to +20oC


Beta Paint

BC-498 consists of a specially formulated plastic scintillator dissolved in an organic solvent. It is intended for the experimenter who wishes to apply thin coatings of plastic scintillator to various substrates.

The material can be applied by brush or by spraying. BC-498 can also be used to make thin films up to 100 microns thick. The most frequently used methods are evaporation or spinning.

The standard formula contains 24.7% polymer. An extra thick formula designated BC-498X contains 34.4% polymer and is recommended for spinning. [Reference "Spin Coating Thin Films of Plastic Scintillator" E. Norbeck et al., Nucl. Inst. & Meth., A262 (1987) 564-547]

BC-498 is most often used to develop sensors for alphas, betas, and heavy ions.

500 ml Ordering Part number: 6498-00003
1 liter Ordering Part number: 6498-00002
Scintillation Properties
Light Output, %Anthracene 65
Decay Constant, main component (ns) 2.4
Wavelength of Max. Emission, nm 423
Atomic Composition
No. of H Atoms per cc (x1022) 5.24
No. of C Atoms per cc (x1022) 4.73
Ratio H:C Atoms 1.11
No. of N Atoms per cc (x1019) 3.50
No. of O Atoms per cc (x109) 3.50
No. of Electrons per cc (x1023) 3.36
General Technical Data
Base Polyvinyltoluene
Refractive index 1.58
Flash Point 26.7°C
Softening Point 70°C




Optical Grease

Temporarily out of stock due to supply chain shortage - check back for status

BC-631 is a clear, colorless, silicone, optical coupling compound that features excellent light transmission and low evaporation and bleed at 25oC.  It has a specific gravity of 0.976 and 1.465 Index of Refraction. It is not recommended that BC-631 optical grease be used with a Teflon reflector except for temporary optical coupling.

We supply this single component formulation in a jar.

Size: 113 g (~ 125 ml) Ordering Part number: 6631-0113
Size: 453 g (~ 500 ml) Ordering Part number: 6631-0453

Data Sheets

BC-490 Plastic Scintillator Casting Resin

PDF | 155.37 KB
Data Sheets

BC-621 Reflector Paint for Plastic Scintillators

PDF | 207.43 KB
Data Sheets

BC-622A Reflector Paint for Liquid Scintillator Tanks

PDF | 141.2 KB