M.E. TAYLOR ENGINEERING INC. HAS BEEN MANUFACTURING, COATING AND RECOATING QUALITY SCINTILLATORS FOR NEARLY 50 YEARS!
Our goal is to help you purchase the best scintillator or light pipe for your needs – and maintain it for its lifetime!
CHOOSING THE RIGHT SCINTILLATOR
|SIDE-BY-SIDE COMPARISON OF POPULAR SCINTILLATORS|
|P47 on BK7||Organic Plastic
|PEAK EMISSION WAVELENGTH||400 nm||408 nm||560 nm||375 nm||420 nm|
|RELATIVE LIGHT OUTPUT (%NaI:TI)||~80||~30||15||40||80|
|DECAY TIME||40 ns||1.8 ns||70 ns||~27 ns||42 ns|
|LIFETIME||Medium||Short||Very Long||Very Long||Very Long|
|LEAD TIME||In Stock||In Stock||4-6 Weeks||4-6 Weeks||2-3 Weeks|
|Peak Emission Wavelength: It is important to match the characteristics of the equipment that will process the light generated by the scintillator with the characteristics of the scintillator itself. In the case of an SEM, each PMT is designed to operate over a specific band of wavelengths. If your scintillator produces photons that are outside this band, you will not be able to image your sample.|
|Relative Light Output: The higher the output of the scintillator, the lower the gain requirements of the system. This is a key characteristic of any scintillator. It describes how effective the scintillator is at doing its job: converting incident radiation to light.|
|Decay Time: The lower the decay time, the shorter each fluorescent event. This allows for the processing of more incident radiation per unit of time. For example, if you are scanning at TV rates, you will require a scintillator that is relatively fast - or one that has a lower decay time.|
|Lifetime: This describes the durability of the scintillator. A longer lifetime means the scintillator can be in use for a longer period of time without the need for replacement. If you use your instrument seldomly or if other characteristics are more important, perhaps lifetime can be sacrificed.|
|Cost: The relative price of each replacement scintillator.|
|Lead Time: The amount of time required to obtain each scintillator. Since the single-crystal scintillators are more expensive, we keep very few in stock. As a result, they must be machined, polished and coated to order.|
UNIQUE SOLUTIONS, TAYLOR-ED TO YOUR NEEDS
Can't decide or not seeing what you need?
We are here to answer your questions and help you find the best choice for your application. We also offer customizations!
- Custom-Made Scintillators
- Custom-Made Light Pipes – Although our standard Light Pipes are coated with P47 phosphor, we can obtain collars that allow for interfacing scintillator discs and Light Pipes (including single crystal scintillators)
- Coating, Polishing and Recoating – Quick turnaround!
- Light Pipe Recoating Service – Just ship us your used light pipe and we will repolish the faces and redeposit the P47 phosphor (Aluminum coating, if requested, is extra).
- In-House SEM – Samples with high resolution pictures SEM
For pricing and details see our SEM Services section of our website
MORE ABOUT SCINTILLATORS
Theory of Scintillation
A scintillator is a material that accepts incident high-energy electromagnetic or charged particle radiation and in turn uses that energy to fluoresce photons whose peak emission wavelength is longer than the wavelength of the incoming radiation. In the case of a Scanning Electron Microscope (SEM), the scintillator disc collects the secondary electrons that are produced as the electron beam scans the surface of the sample. These electrons are converted into photons which travel through the light pipe to the photomultiplier tube (PMT) so that the signal may be amplified to the level required for viewing. The importance of the scintillator in these types of systems cannot be overstated.
Why does the scintillator degrade?
All scintillators will degrade over time; some will degrade faster than others. In the past, the radiation doses received by organic scintillators cut their lifetime short. Today, improvements in scintillator design have greatly extended the useful lifetime of these scintillators. If your plastic scintillator is degrading, you may notice that you must adjust the gain higher and higher to obtain an image as bright as one you may have obtained when the scintillator was new. A more common reason for degradation of any scintillator, regardless of composition, is chamber contamination. Oil vapors contaminate the surface of the scintillator, forming a barrier to incoming electrons. Even turbo or ion pumped systems having an oil based roughing pump have this problem in the long run. Outgassing of the sample and adhesives used to attach the samples also produce contamination. Once you replace your scintillator, you will see an improved image since more of your signal is being processed.
How often should the scintillator be changed?
That depends on the type of scintillator you are using and how often your instrument is used. In the case of our most popular scintillator, the P47 type, and assuming average use, the scintillator should be changed once a year. If your system experiences heavy use (i.e. daily operation) you will probably need to change it more often. However, if you have a single crystal scintillator you can operate for much longer with less down time. Each single crystal scintillator is coated with 50 nm of Aluminum. If contaminants build up on the surface of this type of scintillator, the Aluminum coat can be stripped and reapplied to the crystal. This type of refurbishment is inexpensive and can be performed within 1 day of being shipped back here. Under normal use, this type of scintillator may last years before an Aluminum re-coat is needed. The crystal itself may outlive your instrument!
Can I change the scintillator myself?
YES, IN MOST SEM'S. Your service manual should include easy to follow directions. If not, call the manufacturer for assistance. Since the scintillator is considered a consumable it is not usually covered under standard service contracts. It has been our experience that if your service engineer is doing routine maintenance and you have one on hand they will gladly replace it. It is a good idea to keep at least one spare in stock so that it is immediately available if needed. Assuming the scintillator is kept in its original container it will last many years. The material on the surface of the disc is fragile so please handle with care. It has been our company policy to replace, at no charge, any scintillator (purchased from us) damaged during installation. There are limitations and conditions to this policy.
Want a longer time between scintillator changes and a cost savings overall?
Consider our new ITO-GOLD (pronounced eye-to-gold) SEM Scintillator
Our new ITO-GOLD (pronounced eye-to-gold) SEM scintillator consists of a quartz substrate that is plated with indium tin oxide (conductive and transparent) to which a gold plated ring is electrically bonded. The P47 phosphor is then deposited.
- Better Electrical Contact – the gold retaining ring makes better electrical contact with the scintillator without cutting into the phosphor material
- Signal-to-Noise Ratio is Better – due to a decrease in the electronic noise created by a good electrical bond. There is a conductive layer under the phosphor that uniformly applies the bias voltage (10 KV usually)
- Aluminum Overcoat is not Required – In the event a pinhole develops in the phosphor, the exposed glass surface will not charge up
- Easy Installation – Easier to handle during installation