Appendix C

1. Read ALOUD all of these instructions through section VII, "Tools Needed," before doing anything else.

2. Next assemble all of the needed materials and tools.

3. Then read ALOUD ALL of each section following Section VII before beginning to make the part described in that section.

1. charging and reading the KFM before exposure;

2. exposing it to radiation for a specified time in the location where measurement of the dose rate is needed -- when outdoors, positioning the KFM about 3 ft. above the ground;

3. reading the KFM after its exposure;

4. calculating, by subtraction, the difference between the reading taken before exposure and the reading taken after exposure;

5. using this table to find what the dose rate was during the exposure -- as will be described later.

A. An Uncharged KFM. The charging wire has been pulled to one side by its adjustment-thread. This photo was taken looking straight down at the upper edges of the two flat, 8-ply aluminum leaves. At this angle the leaves are barely visible, hanging vertically side by side directly under the zero mark, touching each other and with their ends even. Their suspension-threads insulate the leaves. These threads are almost parallel and touch (but do not cross) each other where they extend over the top of the rim of the can.

B. Charging a KFM by a Spark-Gap Discharge from a Tape That Has Been Electrostatically Charged by Being Unwound Quickly. Note that the charged tape is moved so that its surface is perpendicular to the charging-wire.
The high-voltage electrostatic charge on the unwound tape (that is an insulator) jumps the spark-gap between the tape and the upper end of the charging-wire, and then flows down the charging-wire to charge the insulated aluminum- foil leaves of the KFM. (Since the upper edges of the two leaves are 3A inch below the scale and this is a photo taken at an angle, both leaves appear to be under the right side of the scale.)

C. A Charged KFM. Note the separation of the upper edges of its two leaves. The charging- wire has been raised to an almost horizontal position so that its lower end is too far above the aluminum leaves to permit electrical leakage from the leaves back up the charging-wire and into the outside air.
Also note the SEAT, a piece of pencil taped to the right side of the can, opposite the charging wire.

D. Reading a KFM. A 12- inch ruler rests on the SEAT and is held vertical, while the reader's eyebrow touches the upper end of the ruler. The lower edge of the right leaf is under 8 on the scale and the lower edge of the left leaf is under 6 on the scale, giving a KFM reading of 14.
For accurate radiation measurements, a KFM should be placed on an approximately horizontal surface, but the charges on its two leaves and their displacements do not have to be equal.

NOTE: In these photos, the paper scale is taped to the top of the transparent plastic-film cover. It is better to tape the scale to the under side of the cover, where it is less likely to be damaged.

1. Any type metal can. approximately 2-9/16 inches in diameter inside and 2-7/8 inches high inside, washed clean with soap. (This is the size of a standard 8-ounce can. Since most soup cans, pop cans, and beer cans also are about 2-9/16 inches in diameter inside, the required size of can also can he made by cutting down the height of more widely, available cans as described in Section IX of these instructions.)

2. Standard aluminum foil - 2 square feet. (In 1987, 2 square feet of widely sold U.S. brands of aluminum foil weighed between 8.0 and 8.5 grams. One gram equals 0.035 ounce.) (If only "Heavy Duty" or "Extra Heavy Duty" aluminum foil is available, make 5-ply leaves rather than 8-ply leaves of standard foil; the resultant fallout meter will he almost as accurate.)

3. Doorbell-wire, or other light insulated wire (preferably, but not necessarily) a single-strand wire inside the insulation -- 6 inches.

4. Any type of clean, fine thread that has not been anti-static treated will serve to suspend a KFM's leaves. (Almost all kinds of sewing thread and fly-tying thread manufactured in 1987 are anti-static treated, are poor insulators, and are unsatisfactory.) In 1987 the best widely available excellent insulating thread is unwaxed dental floss; floss is not anti-static treated. Most unwaxed dental floss is too thick and stiff for properly suspending KFM leaves, but, since dental floss is not a twisted thread, you can make flexible strand-threads from it. Make each no more than one- quarter as thick as the floss, and about 12 inches lung. First separate several strands at the end of the floss outside its dispenser. Then separate strands while pulling one way on the end of the strand-thread that you want and the other way on the unwanted strands. Use only a clean needle to touch and separate the strands in the middle 6 inches of the 12-inch-long piece of unwaxed dental floss.

A widely sold dental floss. Johnson and Johnson's Extra Fine Unwaxed, drawn out of its dispenser without splitting it, makes quite satisfactory leaf-supporting threads. However, better leaf-supporting threads can be made by first separating any dental floss into thinner, more flexible threads

Very thin monofilament fishing line or leader is an excellent insulator. The 2-pound- test strength, such as Du Pont's "Stren" monofilament fishing line, is best. "Trilene" 2-pound "nylon leader." a monofilament manufactured by Berkley and Company, also is excellent. (A 4-pound monofilament line will serve, but is disadvantageously stiff.) Some modern monofilament lines or leaders such as "Trilene" contain an additive that makes them pliant, but also makes them poorer insulators for the first several hours after being taken out of their dispenser and used to suspend the leaves of a KFM. However, in about 6 hours the silica gel or anhydrite drying agent in a KFM removes this additive and the monofilament becomes as good an insulator as even strands of unwaxed dental floss.

To minimize the chance of using a piece of monofilament or other thread that has been soiled and thus changed into a poor insulator, always first remove and discard the outermost layer of thread on any spool that has not been kept clean in a plastic bag or other packaging after being initially unwrapped.

During a worsening crisis or after an attack, neither thread that has not been anti-static treated, nor unwaxed dental floss, nor clean 2-pound or 4-pound monofilament line may be available. However, most American homes have an excellent insulator, very thin polyethylene film - especially clean dry cleaners' bags. A narrow insulating strip cut only 1/16 inch wide can be used to suspend each KFM leaf, instead of an insulating thread. (Installed leaves suspended on strips of thin plastic film must be handled with care.)

To cut 1/16-inch-wide strips from very thin polyethylene film, first cut a piece about 6 x 10 inches. Tape only the two 6-inch-wide ends to a piece of paper (such as a brown grocery bag), so that the film is held flat and smooth on the paper. Make 10 marks. 1/16-inch apart, on each of the two tapes that are holding the film. Place alight so that its reflection on the film enables you to see the edge of the film that you are preparing to cut. Then use a very sharp, clean knife or clean razor blade, guided by the edge of a firmly held ruler, to cut 9 strips, of which you will select the best two. When cutting, hold the knife almost horizontal, with the plane of its blade perpendicular to the taped-down film. Throughout this procedure avoid touching the center parts of the strips.

5. A piece of clear plastic film - a 6 x 6 inch square. Clear vinyl (4 mils thick) used for storm-proofing windows is best, but any reasonably stout and clear plastic will serve. The strong clear plastic used to wrap pieces of cheese, if washed with hot water and soap, is good. Do not use weak plastic or cellophane. Plastic film made from cellulose (such as Flex-O-Pane) and roasting bags are too permeable to water vapor.

6. Cloth duct tape ("silver tape"), or masking tape, or freezer tape, or Scotch-type tape -about 10 square inches. (A roll of Scotch Magic Transparent Tape, if available, should be saved for use in charging the KFM).

7. Band-Aid tape, or masking tape, or freezer tape, or Scotch transparent tape, or other thin and very flexible tapes -- about 2 square inches.

8. Gypsum wallboard (sheetrock) -- about 1/2 square foot, best about 1/2 inch thick, for a good homemade drying agent. (Silica gel with dark blue color indicator is an even better drying agent, but is not available in most communities. Available from chemical supply firms that supply high school chemistry classes. With dark blue silica gel in the bottom of a KFM, white typing correction fluid or white ink is needed to make the lower edges of a KFM's aluminum leaves easier to see.)

9. Glue -- not essential, but useful to replace Band-Aid and other thin tapes. "One hour" epoxy is best. Model airplane cement is satisfactory.

10. An ordinary wooden pencil and a small toothpick (or split a small sliver of wood.)

11. Two strong rubber bands, or string.

12. Several small, transparent plastic bags, such as sandwich bags, to cover the KFM when it is exposed where fallout particles may get on it and contaminate it. Or pieces of thin, transparent plastic film, such as that from bread bags. Also small rubber bands or string.

1. Most hard plastic rubbed on dry paper. This is the best method.

2. Scotch Magic Transparent tape (3/4 inch width is best), or Scotch Transparent Tape, or PVC. (Polyvinyl chloride) insulating electrical tapes, or a few of the other common brands of Scotch type tapes. (Some plastic tapes do not develop sufficiently high voltage electrostatic charges when unrolled quickly.) This method cannot be used for charging a KFM inside a dry-bucket, needed for charging when the air is very humid..

1. A watch with a second hand.

2. A flashlight or other light, for reading the KFM in a dark shelter or at night.

3. Pencil and paper -- preferably a notebook.

1. A large bucket, pot, or can, preferably with a top diameter of at least 11 inches.

2. Clear plastic (best is 4-mil-thick clear plastic used for storm windows). A square piece 5 inches wider on a side than the diameter of the bucket to be used.

3. Cloth duct tape, one inch wide and 8 feet long (or 4 ft., if 2 inches wide). Or 16 ft. of freezer tape one inch wide.

4. Two plastic bags 14 to 16 inches in circumference, such as ordinary plastic bread bags. The original length of these bags should be at least 5 inches greater than the height of the bucket.

5. About one square foot of wall board (sheetrock), to make anhydrite drying agent.

6. Two 1-quart Mason jars or other airtight containers, one in which to store anhydrite and another in which to keep dry the KFM charging devices.

7. Strong rubber bands -- enough to make a loop around the bucket. Or string.

1. An airtight container (such as a large peanut butter jar) with a mouth at least 4 inches wide, in which to keep a KFM, along with some drying agent, when it is not being used. Keeping a KFM very dry greatly extends the time during which the drying agent Inside the KFM remains effective.

2. Commercial anhydrite with a color indicator, such as the drying agent Drierite. This granular form of anhydrite remains light blue as long as it is effective as a drying agent; it turns pink when it becomes ineffective. Or use silica gel with color indicator, that is dark blue when effective and that turns light pink when it becomes ineffective. Heating in a hot oven or in a can over a fire reactivates them as drying agents and restores their blue color. Obtainable from laboratory supply sources. Use enough to cover the bottom of the KFM's can no more than 1/2 inch deep.

3. Four square feet of aluminum foil, to make a moisture-proof cover for the dry-bucket.

1. For a KFM to measure radiation accurately, the air inside its ionization chamber must be kept very dry. An excellent drying agent (anhydrite) can be made by heating the gypsum in ordinary gypsum wallboard (sheetrock). Do NOT use calcium chloride.

2. Take a piece of gypsum wallboard approximately 12 inches by 6 inches, and preferably with its gypsum about 3/8 inches thick. Cut off the paper and glue, easiest done by first wetting the paper. [Since water vapor from normal air penetrates the plastic cover of a KFM and can dampen the anhydrite and make it ineffective in as short a time as two days, fresh batches of anhydrite must be made before the attack and kept ready inside the shelter for replacement. The useful life of the drying agent inside a KFM can be greatly lengthened by keeping the KFM inside an airtight container (such as a peanut butter jar with a 4-inch-diameter mouth) with some drying agent, when the KFM is not being used.]

3. Break the white gypsum filling into small pieces and make the largest no more than 1/2 in. across. (The tops of pieces larger than this may be too close to the aluminum foil leaves.) If the gypsum is dry, using a pair of pliers makes breaking it easier. Make the largest side of the largest pieces no bigger than this.

4. Dry gypsum is not a drying agent. To drive the water out of the gypsum molecules and produce the drying agent (anhydrite), heat the gypsum in an oven at its highest temperature (which should be above 400 degrees F) for one hour. Heat the gypsum after placing the small pieces no more than two pieces deep in a pan. Or heat the pieces over a fire for 20 minutes or more in a pan or can heated to a dull red.

5. If sufficient aluminum foil and time are available, it is best to heat the gypsum and store the anhydrite as follows:

6. Since anhydrite absorbs water from the air very rapidly, quickly put it in a dry airtight container while it is still quite hot. A Mason jar is excellent.

7. To place anhydrite in a KFM, drop in the pieces one by one, being careful not to hit the leaves or the stop-threads. The pieces should almost cover the bottom of the can, with no piece on top of other pieces.

8. To remove anhydrite from a KFM, use a pair of scissors or tweezers as forceps, holding them in a vertical position and not touching the leaves.

1. Remove the paper label (if any) from an ordinary 8-ounce can from which the top has been smoothly cut. Wash the can with soap and water and dry it. (An 8-ounce can has an inside diameter of about 2-9/16 inches and an inside height of about 2-7/8 inches.)

2. Skip to step 3 if an 8-ounce can is available. If an 8-ounce can is not available, reduce the height of any other can having an inside diameter of about 2-9/16 inches (such as most soup cans, most pop cans, or most beer cans). To cut off the top part of a can, first measure and mark the line on which to cut. Then to keep from bending the can while cutting, wrap newspaper tightly around a stick or a round wooden tool handle, so that the wood is covered with 20 to 30 thicknesses of paper and the diameter (ideally) is only slightly less than the diameter of the can.

One person should hold the can over the paper-covered stick while a second person cuts the can little by little along the marked cutting line. If leather gloves are available, wear them. To cut the can off smoothly, use a file, or use a hacksaw drawn backwards along the cutting line. Or cut the can with a sharp, short blade of a pocketknife by: (1) repeatedly stabbing downward vertically through the can into the paper, and (2) repeatedly making a cut about 1/4 inch long by moving the knife into a sloping position, while keeping its point still pressed into the paper covering the stick.

Next, smooth the cut edge, and cover it with small pieces of freezer tape or other flexible tape.

3. Cut out the PAPER PATTERN TO WRAP AROUND KFM CAN. (Cut one pattern out of Pattern Page A.) Glue (or tape) this pattern to the can, starting with one of the two short sides of the pattern. Secure this starting short side directly over the side seam of the can. Wrap the pattern snugly around the can, gluing or taping it securely as it is being wrapped. (If the pattern is too wide to fit flat between the rims of the can, trim a little off its lower edge.)

4. Sharpen a small nail, by filing or rubbing on concrete, for use as a punch to make the four holes needed to install the stop-threads in the ionization chamber (the can). (The stop-threads are insulators that stop the charged aluminum leaves from touching the can and being discharged.)

5. Have one person hold the can over a horizontal stick or a round wooden tool-handle, that ideally has a diameter about as large as the diameter of the can. Then a second person can use the sharpened nail and a hammer to punch four very small holes through the sides of the can at the points shown by the four crosses on the pattern. Make these holes just large enough to run a needle through them, and then move the needle in the holes so as to bend back the obstructing points of metal.

6. The stop-threads can be installed by using a needle to thread a single thread through all four holes. Use a very clean thread, preferably nylon, and do not touch the parts of this thread that will be inside the can and will serve as the insulating stop-threads. Soiled threads are poor insulators.

1. Cut out a piece of standard aluminum foil approximately 4 inches by 8 inches.

2. Fold the aluminum foil to make a 2-ply (= 2 thicknesses) sheet approximately 4 inches by 4 inches.

3. Fold this 2-ply sheet to make a 4-ply sheet approximately 2 inches by 4 inches.

4. Fold this 4-ply sheet to make an 8-ply sheet (8 sheets thick) approximately 2 inches by 2 inches, being sure that the two halves of the second-fold edge are exactly together. This third folding makes an 8-ply aluminum foil sheet with one corner exactly square.

5. Cut out the FINISHED-LEAF PATTERN, found on the following Pattern Page B. Note that this pattern is NOT a square and that it is smaller than the 8-ply sheet. Flatten the 8 thicknesses of aluminum foil with the fingers until they appear to be a single thin, flat sheet.

6. Hold the FINISHED-LEAF PATTERN on top of the 8-ply aluminum foil sheet, with the pattern's THIRD-FOLD EDGE on top of the third-fold edge of the 8-ply aluminum sheet. Be sure that one lower corner of the FINISHED-LEAF PATTERN is on top of the exactly square corner of the 8-ply aluminum sheet.

7. While holding a straight edge along the THREAD LINE of the pattern, press with a sharp pencil so as to make a shallow groove for the THREAD LINE on the 8-ply aluminum sheet. Also using a sharp pencil, trace around the top and side of the pattern, so as to indent (groove) the 8-ply foil.

8. Remove the pattern and cut out the 8-ply aluminum foil leaf. Then, in order to prevent possible excessive electrical discharge from overly sharp points on the lower corners of the leaf, cut about 11/16-inch (triangle) off each of its two lower corners.

9. While holding a straight edge along the indented THREAD LINE, lift up the OPEN EDGE of the 8-ply sheet (keeping all 8 plies together) until this edge is vertical, as illustrated. Remove the straight edge, and fold the 8-ply aluminum along the THREAD LINE so as to make a flat-folded hem.

10. Open the flat-folded hem of the finished leaf until the 8-ply leaf is almost flat again, as shown by the pattern, from which the FINISHED-LEAF PATTERN has already been cut.

11. Prepare to attach the aluminum-foil leaf to the thread that will suspend it inside the KFM.

*If only heavy duty aluminum foil (sometimes called "extra heavy duty") is available, make 5-ply leaves of the same size, and use the table for the 8-ply KFM to determine radiation dose rates. To make a 5-ply leaf, start by cutting out a piece of foil approximately 4 inches by 4 inches. Fold it to make a 4-ply sheet approximately 2 inches by 2 inches, with one corner exactly square. Next from a single thickness of foil cut a square approximately 2 inches by 2 inches. Slip this square into a 4-ply sheet, thus making a 5-ply sheet. Then make the 5-ply leaf, using the FINISHED-LEAF PATTERN, etc. as described for making an 8-ply leaf.

If no epoxy glue* is available to hold down the hem and prevent the thread from slipping in the hem, cut two pieces of tape (Band-Aid tape is best; next best is masking or freezer tape; next best, Scotch tape). After first peeling off the paper backing of Band-Aid tape, cut each piece of tape 1/8 inch by 1 inch long. Attach these two pieces of tape to the finished 8-ply aluminum leaf with the sticky sides up, except for their ends. As shown by the pattern on the following pattern page, secure 1/8 inch of one end of a tape strip near one corner of the 8-ply aluminum foil leaf by first turning under this 1/8-inch end; that is, with this end's sticky side down. Then turn under the other 1/8-inch-long end, and attach this end below the THREAD LINE. Slant each tape strip as illustrated on Pattern (C).

12. Cut an 8-1/2 inch piece of fine, unwaxed, very clean thread that has not been anti-static treated. See INSTRUCTIONS, Page 6 for excellent insulating threads and substitutes. In l986 most sewing threads are anti-static treated and are too poor insulators for use in a KFM.

Cut out Pattern (C), the guide sheet used when attaching a leaf to its suspending thread. Then tape Pattern (C) to the top of a work table. Cover the two "TAPE HERE" rectangles on Pattern (C) with pieces of tape, each piece the size of the rectangle. Then cut two other pieces of tape each the same size and use them to ONTO the thread ONTO the guide sheet, on top of the 'TAPE HERE" rectangles.

Be very careful not to touch the two 1-inch parts of the thread next to the outline of the finished leaf, since oil and dirt even on clean fingers will reduce the electrical insulating value of the thread between the leaf and the top rim of the can.

13. With the thread still taped to the paper pattern and while slightly lifting the thread with a knife tip held under the center of the thread, slip the finished leaf under the thread and into position exactly on the top of the leaf outlined on the pattern page. Hold the leaf in this position with two fingers.

14. While keeping the thread straight between its two taped-down ends, lower the thread so that it sticks to the two plastic strips. Then press the thread against the plastic strips.

15. With the point of the knife, hold down the center of the thread against the center of the THREAD LINE of the leaf. Then, with two fingers, carefully fold over the hem and press it almost flat. Be sure that the thread comes out of the corners of the hem. Remove the knife, and press the hem down completely flat against the rest of the leaf.

16. Make small marks on the thread at the two points shown on the pattern page. Use a ball-point pen if available.

17. Loosen the second two small pieces of tape from the pattern paper, but leave these tapes stuck to the thread.

18. Cut 5 pieces of Band-Aid tape, each approximately 1/8 inch by 1/4 inch, this small.

Use 2 of these pieces of tape to secure the centers of the side edges of the leaf. Place the 5 pieces as illustrated in the SIDE VIEW sketch below. Or use tiny droplets of epoxy, applied with a needle, to secure the side edges and to hold down the hem.

19. To prevent possible partial discharge from overly sharp lower corners of the leaves, use scissors to cut about 1/16 inch ( L) off each lower corner of the two leaves. (Partial discharge from an overly sharp corner may prevent a KFM's leaves from being adequately charged and adequately separated.)

20. To make it easier to take accurate readings:

1. In preparation for suspending the leaves inside the can, make two shallow notches in the top of the rim of the can. Make one notch above each of the two lines ("FASTEN THREADS HOLDING ALUMINUM LEAVES HERE") on the paper Pattern attached to the outside of the can. Make flat-bottomed notches by first filing a V-shaped notch, and then using a fine-toothed hacksaw blade to make the notch rectangular. (If a file and/or a hacksaw blade are not available, the leaf- suspending threads can be taped to the top of the rim of the can.)

2. Use the two small pieces of 'ape stuck to the ends of a leaf-suspending thread to attach the thread to the outside of the can. Attach the tapes on opposite sides of the can, so as to suspend the leaf inside the can. See END VIEW sketch. Each of the two marks on the attached thread MUST rest exactly in a notch (or on the top of the rim of the can, if you are unable to make notches). Be sure that the hem-side of each of the two leaves will face outward. See END VIEW sketch.

3. Position and secure the second leaf, being sure that:

4. Cover with tape the parts of the threads that extend down the outside of the can, and also cover with more tape the small pieces of tape near the ends of the threads on the outside of the can. Or use epoxy or other waterproof glue to attach the parts of the threads on the outside of the can securely to the can.

5. To make the SEAT, cut a piece of a wooden pencil, or a stick, about one inch long and tape it securely to the side of the can along the center line marked SEAT on the pattern. Be sure the upper end of this piece of pencil is at the same position as the top of the location for the SEAT outlined on the pattern. The top of the SEAT is 3/4 inch below the top of the can. Be sure not to cover or make illegible any part of the table printed on the paper pattern.

6. Cut out one of the "Reminders for Operators" and glue and/or tape it to the unused side of the KFM. Then it is best to cover all the sides of the finished KFM with clear plastic tape or varnish. This will keep sticky-tape on the end of an adjustment thread or moisture from damaging the "Reminders" or the table.

1. Cut out the paper pattern for the cover from the Pattern Page (B).

2. From a piece of clear, strong plastic, cut a circle approximately the same size as the paper pattern. (Storm-window vinyl film, 4 mils thick, is best.)

3. Stretch the center of this circular piece of clear plastic over the open end of the can, and pull it down close to the sides of the can, making small tucks in the "skirt," so that there are no wrinkles in the top cover. Hold the lower part of the "skirt" in place with a strong rubber band or piece of string. (If another can having the same diameter as the KFM can is available, use it to make the cover -- to avoid the possibility of disturbing the leaf-suspending threads.)

4. Make the cover so it fit snugly, but can be taken off and replaced readily.

Just below the top of the rim of the can, bind the covering plastic in place with a 1 :4- inch-wide piece of strong tape. (Cloth duct tape is best. Use two thicknesses. If only freezer or masking tape is available, use three or four thicknesses.)

Keep vertical the small part of the tape that presses against the rim of the can while pulling the length of the tape horizontally around the can so as to bind the top of the plastic cover snugly to the rim. If this small part of the tape is kept vertical, the lower edge of the tape will not squeeze the plastic below the rim of the can to such a small circumference as to prevent the cover from being removed quite easily.

5. With scissors, cut off the "skirt" of the plastic cover until it extends only about one inch below the top of the rim of the can.

6. Make a notch in the "skirt," about one inch wide, where it fits over the pencil SEAT attached to the can. The "skirt" in this notched area should be only about 5/8 of an inch long, measured down from the top of the rim of the can.

7. Remove the plastic cover, and then tape the lower edges of the "skirt," inside and out, using short lengths of 1/4-inch-wide tape. Before securing each short piece of tape, slightly open the tucks that are being taped shut on their edges, so that the "skirt" flares slightly outward and the cover can be readily removed.

8. Make the charging-wire by using the full-size, exact-size pattern on the right.

Doorbell wire with an outside diameter of about 1116 inch is best, but any lightweight insulated wire, such as part of a lightweight two-wire extension cord split in half, will serve. The illustrated wire is much thicker than bell wire. To stop tape from possibly slipping up or down the wire, use a very little glue.

If a very thin plastic has been used for the cover, a sticky piece of tape may need to be attached to the end of the bare-ended adjustment thread, so both threads can be used to hold the charging wire in a desired position.

The best tape to attach to an end of one of the adjustment-threads is cloth duct tape. A square piece 3/4 inch by 3/4 inch is the sticky base. To keep this tape sticky (free of paper fibers), the paper on the can should be covered with transparent tape or varnish. A piece about 1/8 inch by 314 inch serves to stick under one end of the sticky base, to hold the adjustment-thread. A 3/4 inch by 1- 1/4 inch rectangular piece of tape is used to make the finger hold -- important for making adjustments inside a dry-bucket.

With a needle or pin, make a hole in the plastic cover 1/2 inch from the rim of the can and directly above the upper end of the CENTER LINE between the two leaves. The CENTER LINE is marked on the pattern wrapped around the can. Carefully push the CHARGING-WIRE through this hole (thus stretching the hole) until all of the CHARGING-WIRE below its Band-Aid-tape stop is inside the can.

9. From the Pattern Page (B) cut out the SCALE. Then tape the SCALE to the under side of the plastic cover, in the position shown on the pattern for the cover, and also by the drawings. Preferably use transparent tape. Be careful not to cover with tape any of the division lines on the SCALE between 20 on the right and 20 on the left of 0.

10. Put the plastic cover on the KFM can.

1. Charging a KFM with Hard Plastic Rubbed on Dry Paper.

2. Charging a KFM from a Quickly Unwound Roll of Tape. (Quick unwinding produces a harmless charge of several thousand volts on the tape.)

1. Be sure the pieces of anhydrite in the bottom of the ionization chamber (the can) are in a single layer, with no piece on top of another and the top of no piece more than 112 inch above the bottom of the can.

2. Check to be sure that the threads suspending the leaves are not crossed; then try to charge the KFM again.

3. If the KFM still cannot be charged, replace the used anhydrite with fresh anhydrite.

4. If you cannot charge a K FM when the air is very humid, charge it inside its dry-bucket.

5. If you cannot charge the KFM while in an area of heavy fallout, take it to the place affording the best protection against radiation, and try to charge it there. (A dose rate of several hundred R hr will neutralize the charges on both the charging device and the instrument so rapidly that a K FM cannot be charged.)

1. Remove the handle of a large bucket, pot, or can preferably with a top diameter of at least 11 inches. A 4-gallon bucket having a top diameter of about 14 inches and a depth of about 9 inches is ideal. A plastic tub approximately this size is satisfactory. If the handle-supports interfere with stretching a piece of clear plastic film across the top of the bucket, remove them, being sure no sharp points remain.

2. Cut out a circular piece of clear plastic with a diameter about 5 inches larger than the diameter of the top of the bucket. Clear vinyl 4 mils thick, used for storm windows, etc., is best. Stretch the plastic smooth across the top of the bucket, and tie it in place, preferably with strong rubber bands looped together to form a circle.

3. Make a plastic top that fits snugly but is easily removable, by taping over and around the plastic just below the top of the bucket. One-inch-wide cloth duct tape, or one-inch-wide glass-reinforced strapping tape, serves well. When taping, do not permit the lower edge of the tape to be pulled inward below the rim of the bucket.

4. Cut two small holes (about 1 inch by 2 inches) in the plastic cover, as illustrated. Then make the radial cuts (shown by dotted lines) outward from the small holes, out to the solid-line outlines of the 3 inch by 4 inch hand-holes, so as to form small flaps.

5. Fold the small flaps upward, so they are vertical. Then tape them on their outer sides, so they form a vertical "wall" about 3/4 inch high around each hand-hole.

6. Reduce the length of two ordinary plastic bread bags (or similar plastic bags) to a length that is 5 inches greater than the height of the bucket. (Do not use rubber gloves in place of bags; gloves so used result in much more humid outside air being unintentionally pumped into a dry-bucket when it is being used while charging a KFM inside it.)

7. Insert a plastic bag into each hand-hole, and fold the edge of the plastic bag about 1/2 inch over the taped vertical "wall" around each hand-hole.

8. Strengthen the upper parts of the plastic bags by folding 2-inch pieces of tape over the top of the "wall" around each hand-hole.

9. Make about a quart of anhydrite by heating small pieces of wall-board gypsum, and keep this anhydrite dry in a Mason jar or other airtight container with a rubber or plastic sealer.

10. Make a circular aluminum-foil cover to place over the plastic cover when the dry-bucket is not being used for minutes to hours. Make this cover with a diameter about 4 inches greater than the diameter of the top of the bucket, and make it fit more snugly with an encircling loop of rubber bands, or with string. Though not essential, an aluminum-foil cover reduces the amount of water vapor that can reach and pass through the plastic cover, thus extending the life of the drying agent.

11. Charge a KFM inside a dry-bucket by:

12. Expose the KFM to fallout radiation either by: