Domain: Engineering — Nuclear Engineering
Target concept: Nuclear Radiation Thickness Measurement Experimental Setup

Video generation prompt: The nuclear radiation thickness measurement experimental setup (including a strontium-90 (Sr-90) beta radiation source, detector, thickness adjustment stage, and display screen) places a polyethylene film between the radiation source and the detector. The film thickness is gradually increased from 0.1 mm, and the display readings are observed.

Evaluation guide:
(i) Target concept: Non-contact thickness measurement via beta-particle attenuation in a thin, low-Z film.
Minimum mechanism: Beta particles emitted by the Sr-90/Y-90 source lose energy in the polyethylene mainly through scattering and absorption; increasing the film's thickness reduces the beta flux that reaches the detector; detector electronics convert that flux into a proportional electrical signal; the display converts the signal into a calibrated thickness-equivalent reading. This attenuation is strong enough to register clearly over the sub-millimeter-to-few-millimeter thickness range used here, unlike higher-energy gamma radiation, which would pass through such a thin film with almost no measurable change.
(ii)Storyline: Frame 1–2: Full setup visible. Source (shielded cylinder), film (thin rectangle), detector (cylindrical or box-shaped), stage (mechanical platform with scale), display (digital readout showing initial value). Frame 3–4: Film is placed, visually confirmed between source and detector; display updates to first attenuated value. Frame 5–6: Stage moves forward (visible platform translation); film appears denser/thicker; display updates to lower value. Frame 7–8: Stage moves again; film opacity increases further; display updates again lower. Frame 9–10: All elements remain fixed in position; final display value is stable; no extraneous motion or visual interference. Perspective: Fixed frontal view, full setup in frame, no occlusion, consistent lighting.

Manual:
Experimental Procedure
1. Position the strontium-90 (Sr-90) beta radiation source, detector, thickness adjustment stage, and display screen in alignment.
2. Place polyethylene film between source and detector.
3. Gradually increase film thickness using the stage; observe display readings.
Observation of Experimental Phenomena
- Polyethylene film appears as a uniform, opaque-to-translucent rectangular sheet.
- Display screen shows decreasing numeric values as film thickness increases.
- Detector signal visibly dims with each thickness increment.
Summary of Experimental Principles
Beta radiation attenuation in thin, low-Z materials approximately follows an exponential law over the sub-millimeter-to-few-millimeter range: I = I₀e^(−μx), where μ is the mass/linear attenuation coefficient and x is thickness. Because polyethylene film in this range is thin enough to measurably attenuate beta particles — unlike higher-energy gamma rays, which would pass through with negligible change — increasing thickness detectably reduces the transmitted beta intensity, enabling non-contact thickness measurement.

Prompt Grounding rubric:
level_1: None of the five core elements (the strontium-90 (Sr-90) beta radiation source, the detector, the thickness adjustment stage, the display screen, and the polyethylene film) appears anywhere, and no sequence of increasing film thickness is shown.
level_2: At least one of the five core elements is present (source, detector, stage, or display), and a polyethylene film appears; but no sequential thickness change is shown, and the source, film, detector, and display are never all visible together in one coherent scene.
level_3: All five elements (the Sr-90 beta radiation source, the detector, the thickness adjustment stage, the display screen, and the polyethylene film) are present and identifiable, arranged source → film → detector → display, with the film positioned between source and detector; at least two visibly different film thicknesses are shown (e.g., a thin sheet followed by a visibly thicker one); but there's no ongoing indicator (labeled thickness values, stage movement, or a changing display reading) confirming a progressive increase starting from 0.1 mm.
level_4: The five elements stay correctly positioned in line, the film is visibly placed between source and detector, the display shows at least two distinct readings tied to two distinct film-thickness states, and the thickness adjustment stage visibly moves between those states, though the film's visual thickness scaling looks inconsistent between states (e.g., a thicker film doesn't look any denser or larger than a thinner one), or the display's value changes aren't clearly tied to each stage movement.
level_5: The five elements stay correctly positioned and fully visible throughout, with no occlusion and no repositioning apart from the stage's own controlled motion; the film sits continuously between source and detector; the stage advances in one clear, unidirectional motion; the display shows a distinct reading at each of at least three visually distinguishable film-thickness states, with every reading change clearly timed to a stage movement; and the film's appearance changes only in thickness/opacity across states, never in color or shape.

Scientific and Causal Correctness rubric:
level_1: The radiation source appears to emit visible light or a colored glow, which is inconsistent with an invisible beta source; the detector's reading doesn't respond at all to the film's presence; the display shows numbers with no relation to attenuation; the film changes color, melts, or deforms; or there's no visible causal link between the film's thickness and the display reading.
level_2: The film is present and static, and the display shows some number, but the number doesn't change when the film is introduced or its thickness is altered; or the source/detector show visible light, heat glow, sparks, or another effect inconsistent with an invisible beta radiation source; or the film looks equally transparent regardless of its stated thickness.
level_3: The film sits between source and detector, and the display reading changes once the film is introduced, decreasing (or its attenuation value increasing) as the film looks thicker; but the direction of change is inconsistent across the different thickness states (e.g., it drops and then rises again), or the film's apparent opacity doesn't track its displayed thickness, or the detector still shows an active, undimmed signal even once the film looks thick enough that it should visibly block more radiation.
level_4: The film's opacity increases step by step with its thickness, the display reading decreases (or attenuation value increases) monotonically across every state shown, the detector's output dims progressively, and the source itself stays dark and inert with no visible emission (consistent with expected attenuation behavior), though the film's opacity may jump between states without an intermediate step, the detector's response may lag inconsistently behind the film being placed, or the display update may not line up in time with the stage's movement.
level_5: The film's opacity increases smoothly and continuously with its thickness, with no color shift; the display reading decreases continuously and monotonically across every state; the detector's signal dims proportionally and in sync with each thickness increment; the source stays non-luminous and visually unchanged throughout; there's no unexplained extra effect such as a glowing halo, secondary flash, or film fluorescence; and every step in the causal chain (film placed, attenuation increases, detector signal drops, display updates) is visibly synchronized and points in a consistent direction.

Spatiotemporal Consistency rubric:
level_1: Objects teleport between frames (for example the source vanishes and reappears elsewhere, or the film jumps from the side of the frame straight to the center), the detector spins 90 degrees with no visible motion causing it, the display flickers with no continuity from one frame to the next, the overall lighting swings from bright to dark within a single frame, or a structural part such as the stage platform or detector housing breaks apart or dissolves mid-clip.
level_2: The source and detector are never shown together in the same frame, the film looks detached from the stage or appears to float, the display screen appears cropped or mirrored, the lighting shifts dramatically (e.g., a cast shadow disappears and later comes back), the camera zooms or pans even though the setup calls for a fixed viewpoint, or the stage's movement is jerky, skipping frames or visibly warping.
level_3: The source, detector, stage, display, and film all stay in the same positions relative to each other throughout, with no teleporting or falling apart; the lighting stays even; the camera holds a fixed view with the whole setup continuously visible, though there may be a minor timing slip, such as the film being placed before the stage actually finishes moving, or the display updating more than one clearly separate step after the film settles into place.
level_4: All the elements keep stable positions relative to one another with no lighting, shadow, or perspective oddities; the stage's motion looks smooth and physically real: a straight, gliding movement rather than sliding or floating; the display updates within about one visible beat of the stage settling, though the film's edge may wobble slightly between states, the detector housing may subtly change shape or size between frames, or a reflection on the display may inconsistently appear and disappear.
level_5: Every element keeps identical size, position, orientation, and lighting from frame to frame, with no jitter, warping, or stretching; the stage's motion is a single, smooth, uninterrupted glide; the film stays centered and flush between source and detector at all times; the display's update lines up precisely with the moment the stage stops moving; and the detector housing, source shielding, and stage markings show no distortion, resizing, or flickering occlusion across the whole clip.