McPherson Model 654 Side-on Photomultiplier Tube

The photomultiplier tube (PMT) is among the most popular photosensitive devices in use today. Various tube types and treatments permit use of these detectors from the Extreme Vacuum Ultraviolet (EUV) through the Visible and into the near Infra-Red. Featuring large photosensitive areas, secondary emission multiplication, low dark noise and fast time response - photomultipliers are ideal for a broad range of spectroscopy applications.

The Model 654 provides the user with a light tight housing for mounting 1 1/8" (28-mm) side-on type PMT's. The housing is equipped with RF shielding and has connectors for current output and high voltage (HV) input. Some models are equipped for VUV operation. All 654 assemblies are provided with a socket for a specified tube. Tubes are specified separately.

Model 654 Data Sheet

Additional Information:

Frequently Used Photomultiplier Tubes (PMTs)
Type Range, nm Peak, nm Max. Vdc Sensitivity, uA/lm Typ Amplification Rise Time Transit Time
1P21 300 - 650 400 1250 40 3 x 10^6 2.2 ns 22 ns
1P28 185 - 650 340 1250 40 4.8 x 10^5 2.2 ns 22 ns
R406 400 - 1100 730 1500 20 2 x 10^5 2 ns 22 ns
R928 185 - 930 400 1250 250 1 x 10^7 2.2 ns 22 ns
R955 160 - 900 400 1250 200 1 x 10^7 2.2 ns 22 ns
Part Numbers for the Model 654 Photomultiplier Tube (PMT) Housing Assembly
Part NumberDescription
8105-0654-0 Model 654 Atmospheric use - for 1 1/8" PMT's. Provided with a mounting flange fitting McPherson slits. Requires selection of PMT.
8105-0654-1 Model 654 Vacuum use - for 1 1/8" PMT's. Provided with a mounting flange fitting McPherson slits and a scintillator coated window for use in the vacuum ultraviolet. Requires selection of PMT
8446-1003-0 Replacement Sodium Salicylate coated window for Model 654 detector assembly.

Sample Spectra

example emission spectrum from the hollow cathode lamp

Outline Drawing

McPherson Model 425 Channel Electron Multiplier, Outline Drawing

Select Publications

Abstract: This paper is a report on our effort to use reflectance measurements of a set of amorphous silicon (a-Si) and uranium (U) multilayer mirrors with an uranium oxide overcoat to obtain the optical constants of a-Si and uranium. The optical constants of U, its oxides, and Si, whether crystalline or amorphous, at 30.4 and 58.4 nm in the extreme ultraviolet (EUV) are a source of uncertainty in the design of multilayer optics. Measured reflectances of multilayer mirror coatings do not agree with calculated reflectances using existing optical constants at all wavelengths. We have calculated the magnitude and the direction of the shift in the optical constants of U and a-Si from reflectivity measurements of DC magnetron sputtered a-Si/U multilayers at 30.4 and 58.4 nm. The reflectivity of the multilayers were measured using a UV hollow cathode plasma light source, a 1 meter VUV monochromator, a back-thinned CCD camera, and a channeltron detector. These reflectance measurements were verified by measurements made at LBNL. The reflectances of the multilayer coatings were measured at 14.5 degrees from normal to the mirror surface. The optical constants were calculated using IMD which uses CURVEFIT to fit the optical constants to reflectivity measurements of a range of multilayer mirrors that varied over a span of 150 - 25.0 nm bilayer thickness. The effects of surface oxide and roughness, interdiffusion, and interfacial roughness were numerically subtracted in fitting the optical constants. The (delta) , (beta) determined at 30.4 nm does not well match the values of c-Si published in the literature (HBOC1), but do approach those of a-Si as reported in literature (HBOC). The difference in the optical constants of c-Si and a-Si are larger than can be attributed to differences in density. Why the optical constants of these two materials vary at 30.4 remains an open question.
M. B. Squires, D. D. Allred, R. S. Turley

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