Photomultipliers are still commonly used wherever low levels of light must be detected.

Photomultipliers are constructed from a glass envelope with a high vacuum inside, which houses a photocathode, several dynodes, and an anode.

Photomultipliers with large distances between the photocathode and the first dynode are especially sensitive to magnetic fields.

* Photomultipliers are used in conjunction with scintillators to detect Ionizing radiation by means of hand held and fixed radiation protection instruments, and particle radiation in physics experiments.

* Photomultipliers are used in research laboratories to measure the intensity and spectrum of light-emitting materials such as compound semiconductors and quantum dots.

* Photomultipliers are used in numerous medical equipment designs.

* Photomultipliers are typically used as the detectors in Flying-spot scanners.

* Photomultipliers were the first electric eye devices, being used to measure interruptions in beams of light.

Photomultipliers offer the best possible opportunity to exceed the Johnson noise for many configurations.

The men who speculate on these institutions have, for the most part, come to at least one common conclusion: that many of the great enterprises and associations around which our democracy is formed are in themselves autocratic in nature, and possessed of power which can be used to frustrate the citizen who is trying to assert his individuality in the modern world ''.

Then, with staring eyes and lips drawn thin, Miriam said to the young woman, `` You are ugly -- uglier than you used to be, and you were always very ugly.

She used to tell me, `` When I stand there and look at the flag blowing this way and that way, I have the wonderful, safe feeling that Americans are protected no matter which way the wind blows ''.

The decision maker who acts for the community as a whole must decide whether the objectives pursued and the methods used are appropriate to public policy regarding cultural groups.

his broad but little used investigative powers are confirmed.

When different colors are used, she is just as likely to color trees purple, hair green, etc..

One cannot help wondering whether Molotov and the rest of the `` anti-party group '' are not being used as China's whipping-boys by Khrushchev and his faithful followers.

Proceeds realized from these pageants are used by the Jaycees to help support their various youth, health, welfare and community betterment activities throughout the state.

Since conventional methods are insensitive at the low frequencies of these molecular transitions, the paramagnetic resonance method is being used instead.

The funds recouped by reductions in item 12 above are used: first, to increase the unadjusted allotments to the specified minimum in those States where the unadjusted allotment is less than the minimum allotment ( item 13 above ) ; ;

Solid concrete blocks, relatively heavy and dense, are used for this shelter.

If they are used, the walls and roof should be 10 inches thick to give the same protection as the 8-inch solid concrete blocks.

It is thick, much like an egg plant's skin, so that poison sprays, if they are used, present no hazard to the consumer.

Such locks are nearly always used where the switch points `` face '' oncoming traffic.

Derails -- mechanical track devices that actually guide the wheels off the rails if a train passes a `` stop '' signal -- are used in many instances.

However, some formulas are used more than others.

The compression ratio arrived at with the formula will be the same regardless of whether cubic inches or cubic centimeters are used.

The only way to determine the final combustion chamber volume when such pistons are used is by measuring it with liquid while the cylinder head is bolted to the cylinder block and the piston is in top dead center position.

Photos of Conference Rooms and the General Assembly Hall can be made when these rooms are not being used for meetings.

Besides flathead bronze screws, silicon bronze Stronghold nails ( made by Independent Nail & Packing Co., Bridgewater, Mass. ) are used extensively in assembly and Weldwood resorcinol glue is used in all the joints.

After the frames and transom are set up on the jig and temporarily braced, a piece of three-inch-wide mahogany ( only widths will be given since the 13/16-inch thickness is used throughout ) is butted between frames one and two below the line of the keelson.

One-inch, No. 10 screws are used in both cases.

Glue and 1-1/2-inch, No. 10 screws are used.

Four pieces are used.

In HR-CS AAS background correction is carried out mathematically in the software using information from detector pixels that are not used for measuring atomic absorption ; hence, in contrast to LS AAS, no additional components are required for background correction.

Rather, the sample is evaporated in a controlled manner ( field evaporation ) and the evaporated ions are impacted onto a detector, which may be up to several meters from the specimen.

In the IAP, ions emitted from the surface are recorded and mass analyzed at a detector placed within 12 cm of the tip ( to provide a reasonably large field of view ).

Without time-gating all of the species reaching the detector are analyzed.

Dark bands in the absorption spectrum are due to the atoms in an intervening medium between source and observer, absorbing certain frequencies of the light between emitter and detector / eye, then emitting them in all directions, so that a dark band appears to the detector, due to the radiation scattered out of the beam.

A prior separation stage is necessary and the additives are first separated by high liquid chromatography ( HPLC ) and then determined on-line using a UV and / or visible detector.

" As fact-finders, juries are expected to fulfill the role of lie detector.

To block the excitation light from reaching the observer or the detector, filter sets of high quality are needed.

Most fluorescence microscopes are operated in the Epi-illumination mode ( illumination and detection from one side of the sample ) to further decrease the amount of excitation light entering the detector.

There are a number of detector types and configurations used in NAA.

There are two detector configurations utilised, they are the planar detector, used for PGNAA and the well detector, used for DGNAA.

There are two types of germanium detector, the lithium-drifted germanium or Ge ( Li ) ( pronounced ‘ jelly ’), and the high-purity germanium or HPGe.

Both Ge ( Li ) and HPGe detectors have excellent sensitivity and resolution, but Ge ( Li ) detectors are unstable at room temperature, with the lithium drifting into the intrinsic region ruining the detector.

Attenuation correction: Attenuation occurs when photons emitted by the radiotracer inside the body are absorbed by intervening tissue between the detector and the emission of the photon.

The electrons are detected by an Everhart-Thornley detector, which is a type of scintillator-photomultiplier system.

The Everhart-Thornley detector, which is normally positioned to one side of the specimen, is inefficient for the detection of backscattered electrons because few such electrons are emitted in the solid angle subtended by the detector, and because the positively biased detection grid has little ability to attract the higher energy BSE electrons.

When all parts of the detector are used to collect electrons symmetrically about the beam, atomic number contrast is produced.