颜色峰值波长：605纳米
波长的利益：510nm和600或605纳米
色彩构筑时间：通常在1小时内
颜色改变：未经辐照：清晰;照射：深蓝色
紫外线灵敏度：当暴露在波长小于350纳米时着色。
包装规格：
fwt-60-00：1厘米×1厘米×42-52微米，1000片/盒，每盒卖
fwt- 60 -20t：10x 10厘米张，每张卖
fwt- 60 -20f：15×15厘米，每张卖
fwt- 60- 20：45x 15厘米的自定义尺寸，每张卖
fwt-60-1p 1 dosimeter in aluminum pouch
fwt-60-2p 2 dosimeters in aluminum pouch
fwt-60-3p 3 dosimeters in aluminum pouch
fwt-60-1r 1 dosimeter in small aluminum pouch
fwt-60-2r 2 dosimeters in small aluminum pouch
fwt-60-00
fwt 60 20f radiochromic sheets 15 x 15 cm
fwt-60-20t radiochromic sheets 10 x 10 cm
fwt-60-810 extra thin radiochromic dosimeter,
fwt-80
fwt-81
fwt-85
fwt-86
fwt-70-40m opti-chromic dosimeter for 0.01 to 1 1-4 sets
or 5-9 sets
fwt-70-83m kgy 10+sets
fwt-87 opti-chromic detector holder
fwt-87c spare caps for fwt-87
fwt-92d
fwt-92d-220
fwt-92h
fwt-82
fwt-200
fwt-173
this pal discusses the use, handling,【敏感词】calibration of the fwt
series of radiachromic dosimeters. it gives general use
guidelines as well as a wealth of information gathered over the
years from users【敏感词】the manufacturers. most of the
information needed to use these products is represented here.
i. general
a. dosimeters
this sheet contains information on the fwt-60 series of
dosimeters. this includes:
fwt-60-00 1 cm x 1 cm square
fwt-60-20f 15 cm x 15 cm square
fwt-60-810 8-10 μm thick
fwt also manufactures the opti-chromic series of dosimeters
that are useful for lower doses than the fwt-60 series.
dose range: 0.5 to 200 kgy; dose rate independent to 1012 gy s-1
b. manufacturing
the fwt-60 series of dosimeters are manufactured by far west
technology (fwt) at its factory in goleta, california, usa. the
manufacturing process involves many steps【敏感词】is a proprietary
process. each step of manufacturing is closely monitored for
quality. below is a list of the steps used to manufacture the
dosimeters.
1. manufacturing the dye【敏感词】its components. fwt
manufactures its own dyes that are used in the dosimeters.
this insures that the dye is of high purity【敏感词】quality. the
nylon matrix that holds the dye goes through several
conditioning steps. clear, blemish free dosimeters are the
result of the extra steps in the manufacturing procedures.
2. solvent casting large sheets of dosimeters.
dye/nylon/solvent solutions are evenly spread over
extremely flat sheets of glass. the solvents evaporate
leaving a free standing film which is then peeled from the
glass. the goal in casting the dosimeters is an even
thickness which is best performed by casting the
dosimeters in sheets. no other form of manufacturing has
been found that results in consistent even thickness
dosimeters.
3. drying【敏感词】aging the sheets. the sheets are not completely
dry after peeling. they are hung in cabinets with a
continuous airflow for 3 months to finish the drying/curing
process.
4. cutting the sheets into proper dosimeter size. the sheets
are then cut into the required size. they are usually cut
into 1 cm x 1 cm squares for the fwt-60-00 dosimeters.
5. inspecting【敏感词】sorting each dosimeter. each fwt-60-00
dosimeter is visually checked【敏感词】sorted by thickness. the
thickness of the dosimeters is measured by very sensitive
instruments capable of measuring to 0.0001 mm.
6. pouching【敏感词】packing the dosimeters. some dosimeters are
boxed in quantities of 1000. others are put into foil
pouches, hermetically sealed【敏感词】then boxed.
of course shipping is an additional step that is handled by our
shipping department.
c. chemical composition
the fwt 60 dosimeters are composed of hexa(hydroxyethyl)
pararosaniline nitrile. the matrix that holds the dye is nylon.
the film has a density of approximately 1.15 g/cm3【敏感词】a
composition (by mass) of 63.7％ c, 12.0％ n, 9.5％ h【敏感词】14.8％ o.
d. dosimeter lot numbering
the lot numbers are four digit numbers that are sequential
according to product production run numbers, thus film lots will
not necessarily have consecutive numbers. there is usually only
one lot per year【敏感词】each number is unique.
ii. handling the dosimeters
a. physical handling
the dosimeters are strong soft nylon films. they can be handled
by picking them up with your fingers, but this can be difficult
because they are so thin. picking them up this way will leave
fingerprints which can change the optical density readings and
thus the exposure data. for these reasons we suggest that you
handle the dosimeters with round tipped tweezers, the tweezers
we use.
using radiachromic dosimeters pal-1
pal 1 using radiachromic dosimeters page 2 of 7
b. ambient light
the dosimeters will change color from penetrating radiation and
from uv light below 370 nm. most artificial lights contain some
light in this region【敏感词】will cause a color change in the
dosimeters exposed to the light for very long. sunlight of course
contains a large quantity of uv–even sunlight through a window
will contain enough uv to quickly alter the color of a dosimeter.
for this reason, we recommend a complete survey of the area
where the dosimeters will be exposed to all forms of light. if
the area uses fluorescent lights【敏感词】has some daylight, then the
area will probably need filters.
a simple test for uv exposure is to place several uncovered
dosimeters of known optical density in the area where
dosimeters will be used. leave the dosimeter in the work area,
exposed to ambient light, for 8 hours. if the density change
with the exposure is greater than 0.005 od then the area needs
to be filtered. you may want to filter it even if the test shows
negative since accidental stray light can have quite an effect on
the dosimeter reading. for critical measurements we
recommend always filtering all light sources. this includes
lights on electronic equipment.
filtering can consist of covering fluorescent tubes with filter
sleeves, covering windows with uv film, covering light fixtures
with uv film【敏感词】purchasing uv free products. filters are
available for fluorescent tubes, incandescent lamps【敏感词】for
windows. all of these materials are designed to block uv light
and will do an adequate job of protecting your dosimeters from
exposure.
fwt sells both paper envelopes【敏感词】aluminum laminate pouches
to protect the dosimeters when they are in use during
irradiation. see section c1【敏感词】c2 for information on these
products.
exposing the dosimeters to visible light for prolonged periods (on
the order of days to weeks) may cause a decrease in sensitivity.
this can occur with no change in background od. for this
reason, we recommend storing the dosimeters in the dark.
c. packaging
the dosimeters should be protected during exposure. abrasion,
uv light【敏感词】dirt may all affect the final od reading【敏感词】thus the
calculated dose. protecting the dosimeters is as simple as
putting them inside an envelope【敏感词】a pouch. envelopes protect
the dosimeter from uv, dirt【敏感词】abrasion. pouches also protect
them from humidity change.
