RADAC Magnetic Marker Tapes represent a significant advance in marker tape design. They are easier to work with and considerably longer-lasting than the conventional fabric type.

They are made from hard, yet flexible magnetic rubber faced with white PVC. Embossed lead identification markers are placed either at 5 or 10 cm intervals. The markers are thick enough to ensure visibility on the radiograph without causing glare.

RADAC Magnetic Marker Tapes adhere firmly to all ferrous surfaces, even when painted or wet, yet are easily re-positionable and do not need two-man operation.

Tests show that the tapes stretch less than 5mm oiver a 10m length after having been in full-time service for many months.

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Sharp face markers are generally used for x-radiography and produce a well-defined, clean image on the film.

The flat face style has a greater bulk for use with the more penetrating gamma radiations.

Markers are supplied either unmounted or mounted to 0.73mm thick, rigid white PVC for easy handling.

The charcters available are arrows (sharp face only), capital letters and numerals.

Sharp face markers are measured with reference to the front, sharp face of the character. Flat face markers are measured on the back of the character. Sharp face markers are always, therefore,larger than the flat face characters of the same nominal size.

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RADAC Cassettes-With-Film consist of x-ray films of any desired shape enclosed in disposable plastic cassettes, ready for exposure.

The concept dispels the notion that x-ray films can be provided only in standard rectangular sizes that may be quite unsuitable for specialized applications.

RADAC cassettes are made to fine dimensional tolerances and can be packed with any available type of x-ray film.

Packs may contain just one film or can be multiple-loaded and may include lead foil for special applications.

Films are normally sealed under pressure but certain shapes can be vacuum-packed to exclude all air.

Cassettes-With-Film are in use in the following fields:
• Nuclear industry
• Aircraft engines
• General engineering
• Pressure Vessels
• Weapons and armaments

The use of Ytterbium and the advent of micro-focus x-ray sets has brought increased quality and sensitivity to the technique and widened the range of possible applications still further.

The technique permits critical radiographic examination of things that would be impossible with conventional rectangular-shaped films of standard size.

No time is wasted in the darkroom with scissors and a template. Films are cut precisely to fit the geometry of the job in hand. They are cut with tools that ensure that each film is exactly the same size and shape.

Since the films are tailor-made. the optimum source-film distance can be used giving the best possible definition and sensitivity.

Costly re-takes due to mis-placement of the films are minimized. Films are welded tightly inside PVC envelopes, ensuring the edge of the film is always as close as possible to the outer edge of the cassette. There are no variations and once the technique is established 100% repeatability can be achieved.

They may have lead-foil screens (front, back and/or centre foils) for intensification or scatter-absorbing purposes.

Rectangular films, and certain other shapes, may be vacuum-packed to exclude all air and give perfect film/foil contact.

Cassettes are made from black PVC 300 microns thick, specially formulated to ensure light-tightness under all conditions.

Each one has a colour-coded patch to indicate the type of film enclosed and its expiry date.

Further information is contained in the RADAC booklet ‘Cassettes-With-Film’ available free of charge.

Shaped Films
There are occasions where special shapes are required but because of the size of the films and because fine edge tolerances are not required, Cassettes-With-Film are not ideal. In these cases it is possible to produce specially shaped re-loadable plastic cassettes and a supply of cut films and intensifying screens.

Provided that the shape required is one which can be loaded into a cassette by the normal means in the customer’s darkroom, this often provides an efficient compromise solution to the problem.

The customer benefits from the standardization and repeatability of Cassettes- With-Film without the added cost of disposable cassettes and lead foils.
Re-usable lead intensifying screens with photo-quality card backing are normally supplied cut to shape for use with these cassettes.

PLASTIC CASSETTES

Single-Envelope Cassettes

All types of RADAC Single-Envelope Plastic Cassettes are of the same basic design. They consist of a single envelope, open at one end, through which film and screens are loaded and unloaded.

The open ends of the envelopes fold over, producing an effective light seal. They are then held closed by means of ‘VELCRO’ nylon fastener.

There is an extra finger-tab at the bottom to assist in holding the cassette to the bench for easier and quicker unloading.

Closure is normally made on the shorter side of a rectangular cassette, but special ones, with the opening on the long side, can be made to special order.

One-Seam Reinforced Single-Envelope Cassettes

These represent the first major advance in cassette design since the introduction of ‘VELCRO’ fastening. Constructed in rugged nylon-reinforced PVC, they are made to outlast any other type of flexible cassette.

They are constructed without side-seams – there is just one joint on the back of the cassette. This design overcomes the weakness of other single envelopes that are welded along the sides: there is no tendency to split.

The cassettes are made from specially- formulated, heavy-duty, nylon-reinforced PVC. They are coloured black on the inside for light-tightness and yellow on the outside for easy recognition.

Standard Single-Envelope Cassettes

These are made from 400 micron black PVC and have become, over the years, the standard cassette for industry.

In cold weather PVC hardens and at very low temperatures can become quite brittle and liable to crack.

We do not recommend the use of standard single envelope cassettes in very cold weather and advise great care in loading and unloading them in sub-zero temperatures.

Reinforced Single-Envelope Cassettes

Are made from thin, yet strong PVC/ nylon/PVC laminated material, The nylon reinforcement is in the form of a mesh and reduces the tendency of the PVC to split at the seams, even after much use.

The PVC laminate retains its flexibility in cold climates. Reinforced cassettes are therefore more suitable for use at low temperatures than the standard type.

Heavy-Duty Single-Envelope Cassettes

Are made from double-thickness material consisting of one layer of standard PVC and one layer of the nylon-reinforced material.

This combination produces a cassette capable of withstanding very rough treatment at normal temperatures.

Double-Envelope Cassettes

RADAC Double-Envelope Cassettes consist of two plain, black envelopes without any means of closure.

Film and screens are loaded into the inner envelope, the smaller of the two. This is then inserted, open end first, into the larger, outer envelope. Light tightness is assured because the open end of the inner envelope is up against the closed end of the outer.

They are made from the standard 400 micron material and are clearly marked ‘RADAC BACK’ on both the inner and the outer envelope for easy identification in the darkroom and on site.

The main advantage of double envelope cassettes is that they lie perfectly flat, having neither fold-over ends nor ‘VELCRO’ fastening,

Special Cassettes

• RADAC can also make special cassettes to the customer’s own requirements in any of the available materials. For example:

• Single-envelope cassettes up to 3m long for pipe radiography,

• Weld-size single-envelope cassettes that link together either with press-studs or ‘VELCRO’.

• Cassettes of special sizes and shapes, not necessarily rectangular.

• Precisely cut film and lead intensifying screens can also be supplied.

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• European Standard EN 464-1:1994 (Wire type).

• DIN 54 109 (Wire type).

• ASTM E77-84a/ASME SE747-94 (Wire type).

• EN 462-5 Duplex Wire IQI.

The EN 464-1 and DIN Indicators are made in steel, aluminium and copper and with wire lengths 10, 25 and 50mm.

EN 464-1 indicators are also made in titanium.

The EN 462-5 Indicators relate only to unsharpness and are meant to be used in conjunction with a wire or step-hole type IQI.

All indicators have a serial number for Quality Assurance purposes. From this, measured wire diameters and date of manufacture can be traced.

European Standard Indicators are supplied with a Certificate of Conformity. Certificates for other Indicators can be supplied at an extra charge.

 Duplex Image Quality Indicators

The Duplex IQI is used in many X-ray applications. It is especially made for digital X-ray applications in order to evaluate image unsharpness (film and digital images) and basic spatial resolution in digital images according to EN 13068 (Radioscopy), EN 14784 and ISO 13671 (CR – Computed Radiography with imaging plates), ISO 17636-2 (digital radiography of welds – flat panel detectors) or ASTM E 2597 (characterization of digital detector arrays).  A new ISO is in the works, describing the possibility of using the Duplex IQI for the determination of focal spot sizes on X-ray tubes.

Specifications:

• The IQI consists of 13 wire pairs from 1D with a wire Ø of 0.80mm to 13D with a wire Ø of 0.050mm.

• Wires 1D – 3D are made of tungsten and wires 4D to 13D are made of platinum.

• The wires of platinum and tungsten and are exactly spaced to correspond to the diameter of each pair. The degree of unsharpness is indicated by the number of wire pairs that can be seen. As unsharpness increases, the wires merge to form a single image.

• The wires are cast in a transparent, resistant and dimensional stable plastic material.

• Each IQI is cast with a standard designation and a unique serial number, which is shown on each image. The lead identification reads END (this identification has been submitted to the Technical Committee CEN/TC 138 for approval).

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RADAC follows the standards set by Intex (Radiographic) Limited and together these two companies have been Europe’s specialist manufacturer of lead intensifying screens for more than thirty years. The screens are made from the finest available radiographic lead foil, laminated onto flexible white photographic base card.

The Company has wide experience in the field of industrial radiography. Its prime concern is to produce screens of the highest quality. Each screen is visually examined and selected ones are radiographed. This programme of rigorous quality control ensures that RADAC screens are free from defects that could interfere with the interpretation of the film. The lead surface is not covered With a lacquer coating. The specially formulated lead-rich alloy is hard enough not to cause the transfer of deposits onto the film in normal use.

Uncoated lead also has the advantages higher intensification and the absence of problems associated with uneven coating or melting or partial wearing away of the lacquer.

The surface of the lead has a semi-matt finish and the foil is laminated to its backing by means of a fine, even film of a powerful, radio-transparent adhesive.

Lead and card stay firmly laminated for the life of the screen.

The photographic-quality base-card which forms the support is defect-free, strong and flexible. This means that the screens can be bent over and over again to a small radius, without cracking.

The corners of the screens are rounded to a convenient radius to prevent damage to films and cassettes.

Each screen is clearly stamped with the lead thickness. The larger sizes and those for weld radiography are stamped at each end for easy recognition.

RADAC screens are made in sizes for all world markets. Any special size can be made to order.

Standard metric sizes are cut according to BS 3490:1985 and ISO 5655-1982.

The following lead thicknesses (mm) are available: 0.05, 0.1, 0.125, 0.15, 0.2, 0.25, 0.5, 0.75, 1, 1.5, 2 and 3. Pairs of any thickness combination can be supplied.

Intermediate (centre) screens, with foil on each side of a card support, are available with many lead thicknesses. Most commonly they are supplied as 0.1 mm (0.05/0/.05) or 0.2 mm (0.1/0.1) intermediate screens.

Screens are normally sold in packs of five, ten and twenty-five pairs, but those thicker than 0.25 mm are available only in single-pair packs.

In the packs the screens are placed face-to face and held tightly together between pieces of strong card. Stiffening side-pieces are added to twenty-five packs to prevent flexing of the screens.

The outer wrapping is in the form of a PVC envelope, labelled showing size, pack and thickness.

RADAC screens are protected with a peel-off plastic film which ensures that they reach the customer in perfect condition.

It is essential that the film be removed before the screens are used. Otherwise radiographic quality will suffer.

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