Standart Imaging EXRADIN ION CHAMBERS User manual

Thimble
Ionization Chambers
User Manual

STANDARD IMAGING INC.
7601 Murphy Drive
Middleton, WI 53562-2532
TEL [phone]
TEL [phone]
FAX [phone]
Jul / 2006 ©2006 Standard Imaging Inc.
DOC #80322-14
Thimble
Ionization Chambers
WWW. .COM

4
Warnings and Cautions alert users to dangerous con-
ditions that can occur if instructions in the manual are
not obeyed. Warnings are conditions that can cause
injury to the operator, while Cautions can cause dam-
age to the equipment.
WARNING:
Electrical shock hazard when connected to 300
V bias supply.
WARNING:
Exradin Ion Chambers are intended for quality
assurance and calibration measurements. They
are not intended to be connected to a patient for
real-time dosimetry measurements.
CAUTION:
Proper use of this device depends on careful
reading of all instructions and labels.
CAUTION:
Do not drop, mishandle, or disassemble unit
since it may result in a change of calibration fac-
tor, or damage to thin-walled Thimble tip. Refer
all servicing to qualied individuals.
CAUTION:
Do not sharply bend triax cable. Damage to the
cable may result in high leakage currents.
CAUTION:
Connector end of ionization chamber should not
be submerged.
General Precautions
REF
92705
92706
92722
92718
92720
92721
92700
92725
92711
92712
92713
92714
92723
92726
92729
92734
Model
A1
T1
A1SL
A2
P2
T2
A12
A12S
A14
T14
A14P
T14P
A14SL
A16
A18
A19
This manual applies to the following thimble chamber
models:

5
7601 MURPHY DRIVE
MIDDLETON, WI 53562-2532 USA
WWW.STANDARDIMAGING.COM
PAGE
Table of Contents
General Operation
4General Precautions
5General Operation
7Calibration
8Parts and Accessories
8 General Chamber Specications
9Model 1 Miniature Shonka Chamber
9Model A1SL Slimline Miniature Shonka Chamber
10 Model 2 Spokas Chamber
10 Model A12 Farmer-Type Chamber
11 Model A12S 0.25 cc Farmer-Type Chamber
11 Model 14 Microchamber
12 Model 14P Parallel Plate Microchamber
12 Model A14SL Slimline Microchamber
13 Model A16 Slimline Microchamber
13 Model A18 0.125 cc Slimline Chamber
14 Model A19 Classic Farmer-Type Ion Chamber
14 Service Notes
16 Service Policy
17 Customer Responsibility
18 Warranty
Exradin thimble chambers are attached to a 1.5 m length
of low-noise exible triaxial cable that is terminated by a
triaxial or coaxial connector. The collector of the chamber
is common with the center wire of the cable and the center
contact of the connector. The guard is common with the
inner cable braid and the middle connector contact in the
case of triaxial connectors and the connector body in the
case of coaxial connectors. The shell (outer electrode),
usually ground, is common with the outer braid of the
cable and the connector body in the case of triaxial con-
nectors and the pigtail extending out the rear of coaxial
connectors.
The design of Exradin chambers requires that the collector
and guard operate at essentially the same potential. The
polarizing potential, supplied by an electrometer, is ap-
plied between the shell and the guard as shown in Figure

6
General Operation Continued
1. Either polarity may be applied to the shell and either
the shell or guard may be grounded. Safety and other
considerations recommend grounding the shell, which then
requires an electrometer with a oating input.
All Exradin chambers can support 1000 V between shell
and guard. However, depending on the particular circum-
stance and radiation intensity, as little as 90 V may yield
essentially 100% charge collection.
Figure 1: Thimble Chamber and Electrometer
Because Exradin ionization chambers do not exhibit volt-
age soakage phenomena, readings of ionization current
may be made immediately after application of the polar-
izing potential. However, it is good practice to pause a
minute or two after changing the potential to allow switch-
ing transients induced in the electrometer to completely
subside. Such transients are most evident in the rate
(current) mode.
Operating Instructions
1. With nothing connected to the input jack of the elec-
trometer, turn the power on and wait at least 15 minutes
for warm up.
2. Verify the leakage of the electrometer is within the
manufacturer’s stated acceptable limits.
3. Connect the ionization chamber to the electrometer and
apply 100% voltage bias.
4. Allow the electrometer and ionization chamber system at
least 10 minutes to stabilize, making certain that all cabling
is lying at and unkinked.
5. Verify the leakage of the ionization chamber is within the
manufacturer’s stated acceptable limits. If measured in the
presence of background sources, note that this signal will
add to the leakage of the chamber.

7
As is standard practice for other ionization chambers, it
is recommended that Exradin chambers be calibrated
every (2) years. This calibration should be performed by
an Accredited Dosimetry Calibration Laboratory (ADCL).
Standard Imaging offers calibrations from the University
of Wisconsin ADCL. You need only one purchase order
to cover calibrations, shipping and handling, and service.
Standard Imaging hand carries all instruments to and from
the University of Wisconsin ADCL.
Calibration
General Operation Continued
6. Some electrometers, such as the Standard Imaging
MAX-4000 Electrometer, allow the user to zero the device
at any time. If desired, perform this system zeroing now.
7. Check the system leakage. Take a reading without ex-
posing the chamber to radiation. This reading should be
less than 0.1% of the nal signal expected. If it is not, the
leakage should be subtracted from the signal.
8. Measure atmospheric temperature and pressure.
9. Insert the ion chamber and take at least 3 measurements.
Generally, the measurements should not be moving in only
one direction (i.e. three readings that continue to drop and
hence may not yet be stabilized). If a current measurement
is done, allow sufcient time for value to stabilize.
10. Analyze the data taking into account the average
of the readings, system leakage, temperature/pressure
corrections, calibration factors and any other appropriate
corrections to be made. Keep in mind that the calibration
factor consists of the electrometer calibration and the
ionization chamber calibration factor.
11. When all measurements are completed, set bias volt-
age to 0 VDC, turn off the electrometer and disconnect the
ionization chamber.

8
Parts and Accessories
REF
72122
72125
72123
72126
72129
72128
72141
72206
72207
72161
72159
72162
72163
72164
72160
72138
72139
72725
72762
72140
72169
Description
A1 / A14 Co-60 Cap; 2.0 mm, C552
A1SL / A14SL Co-60 Cap; 2.0 mm, C552
T1 / T14 Co-60 Cap; 4.0 mm, A150
A2 Co-60 Cap; 2.0 mm, C552
T2 Co-60 Cap; 4.0 mm, A150
P2 Co-60 Cap; 4.0 mm, D400
A16 Co-60 Cap; 2.5 mm, C552
A12 Co-60 cap; 2.8 mm, C552
A12S Co-60 cap; 2.8 mm, C552
A12 4 MeV cap; 10.5 mm, Delrin
A12 6 MeV cap; 15.8 mm, Delrin
A12 10 MeV cap; 25.7 mm, Delrin
A12 12 MeV cap; 30.5 mm, Delrin
A12 15 MeV cap; 37.4 mm, Delrin
A12 18 MeV cap; 44.0 mm, Delrin
A14P Co-60 Cap; 2.0 mm, C552
T14P Co-60 Cap; 4.0 mm, A150
A18 Co-60 Cap; 2.0 mm, C552
A19 Co-60 Cap; 2.8 mm, C552
RSVP PhantomTM Adaptation, for models
1, 2, 12, and 14 only
RSVP PhantomTM Adaptation, for models
A1SL, A14SL and A16 only
General Chamber Specications
100%
No greater than 1000 V
Less than 3 x 10-15 A
50 ohms, 29 pF/ft, 1.5 m long
Triaxial BNC Plug (2-Lug, male
pin); others available upon
request
Integral with triaxial connector
(shell of chamber is common with
connector body)
30-70%, non-condensing
15 - 35°C
650 - 770 mm Hg
IEC 60601-11, IEC 607311
Nominal Collection
Efciency:
Maximum Polarizing
Potential:
Nominal Inherent Leakage
Currents:
Low-Noise Triaxial Cable:
Signal Connector:
High Voltage Connector:
Humidity:
Temperature:
Pressure:
Product Standards:
1Designed to Meet

9
Model 1 Miniature Shonka Chamber
A1 (REF 92705)
T1 (REF 92706)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
0.056 cm3
60 R/nC
4.0 mm from tip of chamber
1.0 mm
6.0 mm
1.0 mm
A1 – Shonka Air-Equiv. plastic
C552
T1 – Shonka Tissue-Equiv.
plastic A150
A1SL (REF 92722)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
0.056 cm3
60 R/nC
4.1 mm from tip of chamber
1.0 mm
6.25 mm
1.1 mm
A1SL – Shonka Air-Equiv.
plastic C552
Model A1SL Slimline Miniature Shonka Chamber

10
Model 2 Spokas Chamber
Model A12 Farmer-Type Chamber
A2 (REF 92718)
P2 (REF 92720)
T2 (REF 92721)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
0.5 cm3
6 R/nC
7.0 mm from tip of chamber
4.6 mm
11.5 mm
1.0 mm
A2 – Shonka Air-Equiv. plastic
C552
P2 – Polystyrene Equiv.
plastic D400
T2 – Shonka Tissue-Equiv.
plastic A150
A12 (REF 92700)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
Included 60Co Buildup Cap:
0.65 cm3
5 R/nC
12.9 mm from tip of chamber
1.0 mm
7.1 mm
0.5 mm
A12 – Shonka Air-Equiv.
plastic C552
Wall thickness of 2.8 mm;
constructed of C552

11
Model A12S 0.25 cc Farmer-Type Chamber
A12S (REF 92725)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
Included 60Co Buildup Cap:
0.25 cm3
14 R/nC
5.8 mm from tip of chamber
1.0 mm
7.1 mm
0.5 mm
A12S – Shonka Air-Equiv.
plastic C552
Wall thickness of 2.8 mm;
constructed of C552
A14 (REF 92711)
T14 (REF 92712)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
0.009 cm3
365 R/nC
Approximately 2.0 mm from
tip of chamber
0.33 mm
6.0 mm
1.0 mm
A14 – Shonka Air-Equiv.
plastic C552, Wire, Conduc-
tive Plastic
T14 – Shonka Tissue-Equiv.
plastic A150
Model 14 Microchamber

12
A14P (REF 92713)
T14P (REF 92714)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Window Thickness:
Window Collector Gap:
Outside Diameter of Shell
Collecting Volume:
Shell, Collector, and Guard
Material:
0.002 cm3
1430 R/nC
1.5 mm from tip of chamber
1.5 mm
1.0 mm
1.0 mm
6.0 mm
A14P – Shonka Air-Equiv.
plastic C552
T14P – Shonka Tissue-Equiv.
plastic A150
A14SL (REF 92723)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
0.009 cm3
365 R/nC
Approximately 2.1 mm from
tip of chamber
0.33 mm
6.25 mm
1.1 mm
A14SL – Shonka Air-Equiv.
plastic C552
Model 14P Parallel Plate Microchamber
Model A14SL Slimline Microchamber

13
A16 (REF 92726)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter of Shell
Collecting Volume:
Wall Thickness:
Shell, Collector, and Guard
Material:
Included 60Co Buildup Cap:
0.007 cm3
450 R/nC
Approximately 1.7 mm from
tip of chamber
0.33 mm
3.4 mm
0.5 mm
A16 – Shonka Air-Equiv.
plastic C552, Wire, Conduc-
tive Plastic
Wall thickness of 2.5 mm;
constructed of C552
2.5 mm
A18 (REF 92729)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter Sensitive
Region:
Wall Thickness:
Shell, Collector, and Guard
Material:
Included 60Co Buildup Cap:
0.125 cm3
25 R/nC
4.9 mm from tip of chamber
1.0 mm
6.9 mm
1.0 mm
A18 – Shonka Air-Equiv.
plastic C552
Wall thickness of 2.0 mm;
constructed of C552
Model A16 Slimline Microchamber
Model A18 0.125 cc Slimline Chamber

14
Service Notes
Calibration Cap
Calibration caps constructed of the same material as the
major elements of the chamber are available to provide
more than adequate build-up for Cobalt-60 radiation.
To seat cap on chamber, push cap onto chamber while
slightly rotating clockwise. When the cap is fully seated,
it will bottom on the shell tip and provide a small gap
between the bottom of the cap and shell step. To remove
cap for measurements either in lower energy beams or in
a liquid phantom, merely pull on cap while again rotating
cap clockwise.
Stem (1, 2, 12, 12S, 14 and 14P only)
The two-piece stem conguration is a 1.3 cm OD black
phenolic, with 5.1 and 12.7 cm segments. They are
threaded together and can be separated if desired. Dif-
ferent stem congurations are available. In every case,
the stem is threaded onto the base of the chamber proper.
The stem may be separated from the chamber to provide
greater mobility of the chamber when operating in a liquid
phantom. The cable connector prevents complete removal
of the stem. In unscrewing the stem from the base of the
chamber, the chamber must be gripped in the region be-
tween the shell and stem. Under no circumstances should
the chamber be held by the shell when removing the stem
as such may result in unscrewing of the shell.
A19 (REF 92734)
Collecting Volume:
Nominal Calibration Factor:
Centroid of Collecting Volume:
Collector Diameter:
Outside Diameter Sensitive
Region:
Wall Thickness:
Shell, Collector, and Guard
Material:
Included 60Co Buildup Cap:
0.62 cm3
5 R/nC
12.8 mm from tip of chamber
1.0 mm
7.0 mm
0.5 mm
A19 – Shonka Air-Equiv.
plastic C552
Wall thickness of 2.8 mm;
constructed of C552
Model A19 Classic Farmer-Type Ion Chamber
21.6 mm

15
Stem (A1SL, A14SL, A16, A18 and A19 only)
The one-piece black aluminum stem is an integral part of
the ionization chamber assembly and is not to be removed
under any circumstances.
A1SL, A14SL, A16 0.64 cm OD, 5.5 cm long
A18 0.69 cm OD, 5.5 cm long
A19 1.3 cm OD, 4.6 cm long
Vent Tube
All Exradin ionization chambers now utilize a rugged,
exible tube to allow the chamber to vent. This tube is
sealed to the chamber body and is open to the ambient near
the connector. The triaxial cable of the chamber passes
through this vent tube.
DO NOT attempt to alter or remove this vent tube from
the chamber under any circumstance. Doing so will void
the warranty, allow the chamber to leak if placed in water,
and/or possibly loosen the cable from the chamber thereby
destroying any calibration factor. Any modications should
be only done by Standard Imaging, Inc.
Underwater Operation
All Exradin thimble chambers are inherently waterproof;
they require no sleeves, caps or other devices to achieve
this. For those models with removable stems, removing
any or all segments of the stem from the chamber body will
not effect the waterproofness of the chamber.
Service and Maintenance
There are no user-serviceable parts within these
ionization chambers. Under no circumstance should
the user attempt to repair or disassemble the chamber
and/or connector, as the warranty will become void
and the calibration factor will change. Under normal
use, the chambers should provide years of trouble-
free service.
If assistance is desired in the proper disposal of this
product (including accessories and components), after
its useful life, please return to Standard Imaging.
Service Notes Continued

16
If service, including recalibration, is required, please con-
tact Standard Imaging’s Customer Service department
by phone or email prior to shipping the product. Standard
Imaging’s Customer Service and Technical Service staff will
attempt to address the product issue via phone or email. If
unable to address the issue, a return material authoriza-
tion (RMA) number will be issued. With the RMA number,
the product can be returned to Standard Imaging. It is the
responsibility of the customer to properly package, insure
and ship the product, with the RMA number clearly identi-
ed on the outside of the package. The customer must
immediately le a claim with their carrier for any shipping
damage or lost shipments. Return shipping and insurance
is to be pre-paid or billed to the customer, and the customer
may request a specic shipper. Items found to be out of
warranty are subject to a minimum service fee of 1 hour
labor (excluding recalibrations) for diagnostic efforts and
require a purchase order (PO) before service is performed.
With concurrence from customer, the product may be
replaced if it is unserviceable or if the required service is
cost prohibitive. Products incurring service charges may
be held for payment. Standard Imaging does not provide
loaner products. See the Standard Imaging Warranty and
Customer Responsibility for additional information.
Service Policy
Serialization Information
Standard Imaging products that are serial-
ized contain coded logic in the serial number
which indicates the product, day and year of
manufacture, and a sequential unit number
for identication:
A YY DDD X
A
YY
DDD
X
Unique product ID
Last two digits of the year
(e.g. 1999 = 99, 2000 = 00)
Day of the year (1< DDD < 365)
Unique unit ID Number (1 < X < 9)

17
Customer Responsibility
This product and its components will perform properly and
reliably only when operated and maintained in accordance
with the instructions contained in this manual and accom-
panying labels. A defective device should not be used.
Parts which may be broken or missing or are clearly worn,
distorted or contaminated should be replaced immediately
with genuine replacement parts manufactured by or made
available from Standard Imaging Inc.
CAUTION: Federal law in the U.S.A. and Ca-
nadian law restrict the sale, distribution, or
use of this product to, by, or on the order of a
licensed medical practitioner. The use of this
product should be restricted to the supervision
of a qualied medical physicist. Measurement of
high activity radioactive sources is potentially
hazardous and should be performed by quali-
ed personnel.
Should repair or replacement of this product become
necessary after the warranty period, the customer should
seek advice from Standard Imaging Inc. prior to such
repair or replacement. If this product is in need of repair, it
should not be used until all repairs have been made and
the product is functioning properly and ready for use. After
repair, the product may need to be calibrated. The owner
of this product has sole responsibility for any malfunction
resulting from abuse, improper use or maintenance, or
repair by anyone other than Standard Imaging Inc.
The information in this manual is subject to change without
notice. No part of this manual may be copied or reproduced
in any form or by any means without prior written consent
of Standard Imaging Inc.

18
Warranty
Standard Imaging, Inc. sells this product under the warranty herein set
forth. The warranty is extended only to the buyer purchasing the product
directly from Standard Imaging, Inc. or as a new product from an authorized
dealer or distributor of Standard Imaging, Inc.
For a period provided in the table below from the date of original delivery to
the purchaser or a distributor, this Standard Imaging, Inc. product, provided
in the table is warranted against functional defects in design, materials
and workmanship, provided it is properly operated under conditions of
normal use, and that repairs and replacements are made in accordance
herewith. The foregoing warranty shall not apply to normal wear and tear,
or if the product has been altered, disassembled or repaired other than
by Standard Imaging, Inc. or if the product has been subject to abuse,
misuse, negligence or accident.
Product Warranty Period
Standard Imaging
Ionization Chambers 2 years
Standard Imaging
Well Chambers 2 years
Standard Imaging
Electrometers 2 years
Standard Imaging
BeamChecker Products 2 years
Standard Imaging
Software Products 1 year
All Other Standard
Imaging Products 1 year
Standard Imaging
Custom Products 1 year
Standard Imaging
Remanufactured Products 180 days
Standard Imaging Custom
Select Products 90 days
Consumables 90 days
Serviced Product 90 days
Resale Products As dened by the Original
Equipment Manufacturer
ADCL Product Calibration
(Standard Imaging uses
the UW-ADCL for
recalibrations required
under warranty)
0 - 90 days = 100% of ADCL Calibration Costs
91 - 182 days = 75% of ADCL Calibration Costs
183 – 365 days = 50% of ADCL Calibration Costs
366 – 639 days = 25% of ADCL Calibration Costs
(days from date of shipment to customer)
Standard Imaging’s sole and exclusive obligation and the purchaser’s sole
and exclusive remedy under the above warranties are, at Standard Imag-
ing’s option, limited to repairing, replacing free of charge or revising labeling
and manual content on, a product: (1) which contains a defect covered by
the above warranties; (2) which are reported to Standard Imaging, Inc. not
later than seven (7) days after the expiration date of the warranty period in
the table; (3) which are returned to Standard Imaging, Inc. promptly after
discovery of the defect; and (4) which are found to be defective upon exami-
nation by Standard Imaging Inc. Transportation related charges, (including,
but not limited to shipping, customs, tariffs, taxes, and brokerage fees) to
Standard Imaging are the buyer’s responsibility. This warranty extends to
every part of the product except consumables (fuses, batteries, or glass
breakage). Standard Imaging, Inc. shall not be otherwise liable for any
damages, including but not limited to, incidental damages, consequential
damages, or special damages. Repaired or replaced products are war-
ranted for the balance of the original warranty period, or at least 90 days.
This warranty is in lieu of all other warranties, express or implied,
whether statutory or otherwise, including any implied warranty of t-
ness for a particular purpose. In no event shall Standard Imaging,
Inc. be liable for any incidental or consequential damages resulting
from the use, misuse or abuse of the product or caused by any defect,
failure or malfunction of the product, whether a claim of such dam-
ages is based upon the warranty, contract, negligence, or otherwise.
This warranty represents the current standard warranty of Standard
Imaging, Inc. Please refer to the labeling or instruction manual of your
Standard Imaging, Inc. product or the Standard Imaging, Inc. web page
for any warranty conditions unique to the product.