PIC16F57 24-pin DIP package.
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Short answer: Yes. Any tube that accelerates electrons across a sizeable potential in vacuum and lets them strike solid matter (glass, metal) will produce bremsstrahlung X-rays, plus some characteristic lines from the struck material.
Emax(keV) ≈ kV. Example: a 15 kV supply can produce photons up to ~15 keV.Note: This is a historical/technical explanation, not safety or medical advice. Even low-intensity X-ray sources warrant caution.
Target (anode): Tungsten (often W-Re alloy), sometimes molybdenum or rhodium for mammography.
Window: Beryllium (low absorption) — this is the exit window, not the target.
| Component | Typical Material | Role | Why this material? |
|---|---|---|---|
| Target (Anode Face) | Tungsten (W), W-Re alloy Mo / Rh in mammography |
Converts electron kinetic energy into X-rays | High Z → efficient X-ray production; very high melting point → withstands heat |
| Anode Body / Backing | Molybdenum, graphite | Supports target and dissipates heat | Good thermal conductivity and lower weight |
| Window (Exit Port) | Beryllium (Be) | Allows X-rays to leave the tube | Very low Z → minimal absorption; strong enough to hold vacuum |
| Cathode Filament | Thoriated tungsten | Electron source (thermionic emission) | Durable, high-temp emitter |
| Envelope | Borosilicate glass or metal-ceramic | Maintains hard vacuum | Strength + electrical insulation |
Note: Finished beryllium windows are safe in use, but dust/fumes during machining are hazardous.
Both devices accelerate electrons across a high potential in vacuum and produce X-rays when those electrons strike matter. A modern medical/industrial X-ray tube is essentially a refined, thermionically controlled descendant of the Crookes tube.
| Aspect | Crookes Tube (c. 1870s–1900s) | Modern X-ray Tube / Coolidge Tube (1913→) |
|---|---|---|
| Vacuum level | Partial vacuum; pressure high enough that residual gas ionization plays a role. | Hard vacuum (<10−5–10−7 Torr typical), stable emission and spectra. |
| Cathode / electron source | Cold cathode; electrons drawn from residual gas (glow discharge). Emission depends on pressure and voltage. | Heated filament (thoriated W): thermionic emission gives precise current control (mA). |
| Beam control & stability | Poorly focused; intensity fluctuates with gas pressure and conditioning. | Focusing cup forms a controlled focal spot; independent control of kVp and mA. |
| Anode / target | Often a fixed metal plate or the glass wall; limited heat capacity. | High-Z tungsten (W) target (often W-Re) on Mo/graphite body; rotating anode spreads heat. |
| X-ray exit window | Usually the glass envelope itself (significant absorption, especially at low energy). | Beryllium window (low-Z, low attenuation), preserves softer X-rays. |
| Spectrum characteristics | Variable/unstable; bremsstrahlung from glass/anode with poorly defined characteristic lines. | Predictable bremsstrahlung + characteristic lines (W, Mo, Rh, etc.); filtration selectable. |
| Operating voltage (kVp) | Tens of kV typical; limited by tube conditioning and insulation. | 30–150 kVp (diagnostic); higher for industrial/CT; accurate regulation and ripple control. |
| Tube current (mA) | Small, erratic discharge currents. | mA precisely set (e.g., 50–800 mA in diagnostic bursts); mAs determines output. |
| Heat handling | Minimal; prone to damage at high loads. | Rotating anode + large heat storage; oil bath and external cooling for tube housing. |
| Duty cycle / exposure | Intermittent, exploratory; not metered for imaging. | Timed exposures (ms–s), pulsed operation; load charts specify safe duty cycles. |
| Filtration & beam quality | Little to no intentional filtration; glass strongly self-filters. | Built-in + added filtration (Al, Cu, etc.); inherent Be window preserves useful spectrum. |
| Focal spot | Diffuse; not standardized. | Specified sizes (e.g., 0.3–1.2 mm); line-focus principle improves apparent spot. |
| Applications | Scientific curiosity; fluorescence and cathode-ray studies; Röntgen’s discovery experiments. | Medical radiography/fluoroscopy, CT, mammography; NDT/NDE; crystallography; security. |
| Historical notes | Crookes (1870s); Röntgen observed X-rays (1895) from cathode rays hitting materials. | Coolidge tube (1913) introduces thermionic control; foundation of modern X-ray systems. |
Safety note: Finished beryllium windows are safe in normal use; machining/abrasion hazards pertain to dust/fumes during manufacture.