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{{CRT | |||
|Manufacturer=Tektronix | |||
|Model=T7100 | |||
|Part_nos=154-0783-00 | |||
|Description=[[micro-channel plate CRT]] | |||
|Used_in=7104; R7103 | |||
|Designers=Dennis Hall;Aris Silzars;Conrad Odenthal | |||
}} used in the [[7104]] and [[R7103]] analog 1 GHz scopes. | |||
Compared to non-MCP high-speed tubes, the T7100 uses reduced beam current and acceleration voltage | It features a [[micro-channel plate]] electron beam amplification stage. | ||
to achieve high deflection sensitivity, eliminating the need for high amplifier output voltages, thereby boosting | [[File:Micro-channel plate diagram.jpg | thumb | 550px | right | MCP diagram<br />(click image to enlarge)]] | ||
amplifier bandwidth. | Compared to non-MCP high-speed tubes, the T7100 uses reduced beam current and acceleration voltage to achieve high deflection sensitivity, eliminating the need for high amplifier output voltages, thereby boosting amplifier bandwidth. | ||
The electron beam passes through terminated helical deflection plates (both X and Y axes use | The electron beam passes through terminated helical deflection plates (both X and Y axes use this form of [[distributed deflection plates]] to achieve the necessary bandwidth), followed by an electrostatic scan-expansion lens that increases deflection 4.5 times vertically and 4 times horizontally, before it hits the micro-channel plate (MCP). | ||
this form of [[distributed deflection plates]] to achieve the necessary bandwidth), followed by | The deflection structures are described in [https://patents.google.com/patent/US4093891 US Patent 4,093,891]. | ||
an electrostatic scan-expansion lens that increases deflection 4.5 times vertically and 4 times | The scan-expansion lens is a "box lens" design, which is discussed on pages 53−55 of the ''[[Media:7104_maintenance.pdf|7104 maintenance document]]''. | ||
horizontally, before it hits the micro-channel plate which | |||
The inside walls of these channels are coated with resistive material, with a voltage of 700-1050 V applied | The MCP consists of parallel channels of 25 μm diameter and offset at a slight angle to the beam. | ||
between back and front of the plate. Electrons entering a channel hit the wall where they initiate a cascade | The inside walls of these channels are coated with resistive material, with a voltage of 700-1050 V applied between back and front of the plate. Electrons entering a channel hit the wall where they initiate a cascade of secondary electron emission like in a [https://en.wikipedia.org/wiki/Photomultiplier photomultiplier]. | ||
of secondary electron emission like in a photomultiplier. | |||
A final 10 kV potential accelerates the beam across a 3 mm gap toward the phosphor coating. | A final 10 kV potential accelerates the beam across a 3 mm gap toward the [[phosphor]] coating. | ||
The beam amplification is sufficient to view a [[Media:Tek7104-200ps-singleshot.jpg|single-shot event at 200 ps/Div]] with the naked eye. | The beam amplification is sufficient to view a [[Media:Tek7104-200ps-singleshot.jpg|single-shot event at 200 ps/Div]] with the naked eye. | ||
The Micro-channel plate's amplification degrades irreversibly with operation, in proportion to the log of total charge passed per channel or display area. | |||
For this reason, continued operation with a steady trace and especially at large beam currents must be avoided. | For this reason, continued operation with a steady trace and especially at large beam currents must be avoided. | ||
The 7104 contains a CRT protection circuit that shuts off the beam after a time depending on the beam current. | |||
{{BeginSpecs}} | |||
{{Spec | Screen size | 8 × 10 Div. @ 8.5 mm }} | |||
{{Spec | Resolution | 17 lines / Div. }} | |||
{{Spec | Vertical deflection factor | 1 V/cm }} | |||
{{Spec | Vertical deflection impedance | 200 Ω }} | |||
{{Spec | Vertical bandwidth | 2.6 GHz (3 GHz spec claimed in maintenance document linked below) }} | |||
{{Spec | Horizontal deflection factor | 2 V/Div }} | |||
{{Spec | Horizontal deflection impedance | 365 Ω }} | |||
{{Spec | Horizontal bandwidth | 1.5 GHz }} | |||
{{EndSpecs}} | |||
==Links== | ==Links== | ||
* [http://www.vintagetek.org/wp-content/uploads/2011/10/7104-Springer-article-email-res.pdf Hans Springer: Breakthroughs throughout push scope to 1 GHz] | * [http://www.vintagetek.org/wp-content/uploads/2011/10/7104-Springer-article-email-res.pdf Hans Springer: Breakthroughs throughout push scope to 1 GHz] | ||
* [[Media:7104_maintenance.pdf|7104 maintenance document]], p.30+ | |||
* [[T7101]] | |||
* [[Patent US 4142128A|US Patent 4142128A – Box-shaped scan expansion lens for cathode ray tube]] ([[Conrad Odenthal]]) | |||
* [[Conrad Odenthal]], ''[[Media:Conrad Odenthal - A box-shaped scan expansion lens for an oscilloscope CRT.pdf|A box-shaped scan expansion lens for an oscilloscope CRT]] (1977) | |||
* [[Media:Box lens design being tried by Tektronix in experimental CRTs.pdf|Box lens design being tried by Tektronix in experimental CRTs]] (1977) | |||
==Screen shots | ==Pictures== | ||
<gallery> | |||
Tek 154-0783-00 1.jpg|154-0783-00 T7100 CRT | |||
Tek 154-0783-00 2.jpg|154-0783-00 T7100 CRT | |||
Tek t7100 internal1.JPG|T7100 internal | |||
Tek t7100 internal2.JPG|T7100 internal | |||
Tek t7100 internal3.JPG|T7100 internal | |||
Tek t7100 internal4.JPG|T7100 internal | |||
Tek t7100 internal5.JPG|T7100 internal | |||
Tek t7100 internal6.JPG|T7100 internal | |||
</gallery> | |||
'''Screen shots''' | |||
<gallery> | <gallery> | ||
Tek7104-200ps-singleshot.jpg | 7104 recording a single shot pulse (from [[067-0587-02]]) at 200 ps/Div. Camera: Nikon D7000, 50 mm f/1.4, ISO 3200, 1/2 s. CRT filter not removed. | |||
Tek7104-200ps-singleshot-sin1-1g.jpg | 7104 recording 1 GHz sine, single shot at 500 ps/Div. Camera: Nikon D7000, 50 mm f/1.4, ISO 3200, 1/2 s. CRT filter not removed. CRT amplification loss is evident around the center line. | |||
Tek t7100 lens structure.jpg | |||
</gallery> | </gallery> | ||
[[Category: | [[Category:Micro-channel plate CRTs]] |