T7100: Difference between revisions

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The '''Tektronix T7100'''  (P/N 154-0783-00 with P31 phosphor) is the CRT used in the [[7104]] and [[R7103]] 1 GHz analog scopes.
The '''Tektronix T7100'''  (P/N 154-0783-00 with P31 phosphor) is the CRT used in the [[7104]] and [[R7103]] analog 1 GHz scopes.
It features a [[Micro-channel plate CRT|micro-channel plate]] electron beam amplification stage.
It features a [[Micro-channel plate CRT|micro-channel plate]] electron beam amplification stage.
 
[[File:Micro-channel plate diagram.jpg | thumb | 550px | right | MCP diagram<br />(click image to enlarge)]]
Compared to non-MCP high-speed tubes, the T7100 uses reduced beam current and acceleration voltage
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  
to achieve high deflection sensitivity, eliminating the need for high amplifier output voltages, thereby boosting  
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an electrostatic scan-expansion lens that increases deflection 4.5 times vertically and 4 times  
an electrostatic scan-expansion lens that increases deflection 4.5 times vertically and 4 times  
horizontally, before it hits the micro-channel plate (MCP).
horizontally, before it hits the micro-channel plate (MCP).
The deflection structures are described in US Patent 4,093,891.
The deflection structures are described in [https://patents.google.com/patent/US4093891 US Patent 4,093,891].
The scan-expansion lens is a "box lens" design, which is discussed on pages 53, 54, and 55
The scan-expansion lens is a "box lens" design, which is discussed on pages 53−55
of the "7104 maintenance document" linked below.
of the ''[[Media:7104_maintenance.pdf|7104 maintenance document]]''.


The MCP consists of parallel channels of 25 μm diameter and offset at a slight angle to the beam.
The MCP consists of parallel channels of 25 μm diameter and offset at a slight angle to the beam.
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of secondary electron emission like in a [https://en.wikipedia.org/wiki/Photomultiplier photomultiplier].
of secondary electron emission like in a [https://en.wikipedia.org/wiki/Photomultiplier 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.


[[File:Micro-channel plate diagram.jpg | 750px |MCP diagram]]
The Micro-channel plate's amplification degrades irreversibly with operation, in proportion to the log of total charge passed per channel or display area.   
<br />(click image to enlarge)
 
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.  
To protect the tube, the 7104 contains a protection circuit that shuts off the beam after a time depending on the beam circuit.
The 7104 contains a CRT protection circuit that shuts off the beam after a time depending on the beam current.


==Specifications==
{{BeginSpecs}}
* Screen size: 8 × 10 Div. @ 8.5 mm
{{Spec | Screen size                     | 8 × 10 Div. @ 8.5 mm }}
* Resolution: 17 lines / Div.
{{Spec | Resolution                     | 17 lines / Div. }}
* Vertical deflection factor: 1 V/cm
{{Spec | Vertical deflection factor     | 1 V/cm }}
* Vertical deflection impedance: 200  Ω
{{Spec | Vertical deflection impedance   | 200  Ω }}
* Vertical bandwidth: 2.6 GHz (3 GHz spec claimed in maintenance document linked below)
{{Spec | Vertical bandwidth             | 2.6 GHz (3 GHz spec claimed in maintenance document linked below) }}
* Horizontal deflection factor: 2 V/Div
{{Spec | Horizontal deflection factor   | 2 V/Div }}
* Horizontal deflection impedance: 365 Ω
{{Spec | Horizontal deflection impedance | 365 Ω }}
* Horizontal bandwidth: 1.5 GHz
{{Spec | Horizontal bandwidth           | 1.5 GHz }}
{{EndSpecs}}


==Links==
==Links==

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