EXRADIN Thimble Ion Chambers
Contents
1. Customer Responsibility General Chamber Specifications Model 1 Miniature Shonka Thimble Chamber A1SL Slimline Miniature Shonka Thimble Chamber 10 Model 2 Spokas Thimble Chamber 10 A12 Farmer Type Chamber 11 A12S 0 25 cc Farmer Type Chamber 11 Model 14 Microchamber 12 Model 14 P Parallel Plate Microchamber 12 A14SL Slimline Microchamber 2 A16 Slimline Microchamber Warranty Standard SeeDOS Ltd mM US maging General Operation CODDOANNWND All Exradin thimble chambers are attached to a 1 5 m length of low noise flexible triaxial cable that is termi nated 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 connectors 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 applied between the shell and the guard as shown in Figure 1 Either polarity may be applied to the shell and either the shell or guard may be grounded Safety2. all repairs have been made and the product is functioning properly and ready for use After repair the chamber may need to be calibrated The owner of this device has sole responsi bility 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 General Chamber Specifications E Nominal Collection Efficiency 100 Maximum Polarizing Potential 1000 V Nominal Inherent Leakage Currents 1045A Low Noise Triaxial Cable 50 ohms 29 pF ft 1 5 m long Signal Connector Triaxial BNC Plug 2 Lug male pin unless requested as other High Voltage Connector Integral with triaxial connector shell of chamber is common with connector body Humidity 10 80 non condensing Temperature 15 50 C Pressure 680 770 mm Hg Miniature Shonka Thimble Chamber MODEL 1 A1 REF 92705 M1 REF 92707 T1 REF 92706 4 4 mm 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 cm 60 R nC 4 0 mm from tip of chamber 1 0 mm 6 0 mm 1 0 mm A1 Shonka Air Equiv p
3. and other considerations recommend grounding the shell which then requires an electrometer with a floating input All Exradin chambers can support 1000 V between shell and guard However depending on the particular circumstance and radiation intensity as little as 90 V may yield essentially 100 charge collection General Operation AAA GUARD SHELL Ns COLLECTOR LOW NOISE L a ELECTROMETER Ol Figure 1 Thimble Chamber and Electrometer Because Exradin onization chambers do not exhibit voltage soakage phenomena readings of ionization current may be made immediately after application of the polarizing potential However it is good practice to pause a minute or two after changing the potential to allow switching 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 electrometer 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 flat and unkinked 5 Verify the leakage of the ionization c
4. 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 Customer Responsibility S a zz 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 accompanying 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 replace ment parts manufactured by or made available from Standard Imaging Inc Caution Federal law in the U S A and Canada restricts the sale distribution or use of this device to by or on the order of a licensed medical practitioner The use of this device should be restricted to the supervision of a qualified medical physicist Should repair or replacement of this device become necessary after the warranty period the customer should seek advice from Standard Imaging Inc prior to such repair or replacement If this device is in need of repair it should not be used until
5. 0 5 mm A12 Shonka Air Equiv plastic C552 Wall thickness of 2 8 mm constructed of C552 10 0 25 cc Farmer Type Chamber MODEL A12S A12S REF 92725 7 4mm 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 25 cm 14 R nC 5 8 mm from tip of chamber 1 0 mm 7 1mm 0 5 mm A12S Shonka Air Equiv plastic C552 Included Co Buildup Cap Wall thickness of 2 8 mm constructed of C552 Microchamber MODEL 14 A14 REF 92711 T14 REF 92712 2 0 mm Collecting Volume 0 009 cm Nominal Calibration Factor 365 R nC Centroid of Collecting Volume Collector Diameter Outside Diameter of Shell Collecting Volume Wall Thickness Shell Collector and Guard Material Approximately 2 0 mm from tip of chamber 1 5 mm 6 0 mm 1 0 mm A14 Shonka Air Equiv plastic C552 T14 Shonka Tissue Equiv plastic A150 11 Parallel Plate Microchamber MODEL 14P A14P REF 92713 T14P REF 92714 1 0mm Collecting Volume 0 002 cm 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 1
6. 430 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 Slimline Microchamber MODEL A14SL A14SL REF 92723 gt 2 0 mm 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 cm 365 R nC Approximately 2 1 mm from tip of chamber 1 5 mm 6 25 mm 1 1 mm A14SL Shonka Air Equiv plastic C552 12 Slimline Microchamber MODEL A16 A16 REF 92726 2 7 mm 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 Co Buildup Cap 0 007 cm 450 R nC Approximately 1 7 mm from tip of chamber 0 3 mm 3 4 mm 0 5 mm A16 Shonka Air Equiv plastic C552 Wall thickness of 2 5 mm constructed of C552 13 Notes Notes Warranty gt v zZ ZZ UP e 2um1 zvm 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 of twenty f
7. ZA EXRADIN Thimble lon Chambers User Manual SeeDOS Product User Manual En Standard E iS N Imaging DOC 80322 05 ZA EXRADIN Thimble lon Chambers User Manual Distributed by SeeDOS Ltd For further information or a quotation please contact Colin Walters at cwalters seedos com General Precautions zn _ Warnings and Cautions alert users to dangerous conditions 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 damage to the equipment WARNING Electrical shock hazard when connected to 300 V bias supply 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 change of calibration factor or damage to thin walled Thimble tip Refer all servicing to qualified individuals CAUTION Do not sharply bend triax cable Damage to the cable may result in high leakage currents This manual applies to the following thimble chamber models Model REF A1 92705 M1 92707 T1 92706 A1SL 92722 A2 92718 M2 92719 P2 92720 T2 92721 A12 92700 A12S 92725 A14 92711 T14 92712 A14P 92713 T14P 92714 A14SL 92723 A16 92726 Table of Contents _ E PAGE General Precautions General Operation Service Notes Parts and Accessories List
8. cm long is an integral part of the ionization chamber assembly and is not to be removed under any circumstances Vent Tube All Exradin ionization chambers now utilize a rugged flex ible 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 Removing any segment of the stem will not effect the waterproof ness of the chamber at all 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 modifications 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 Underwater Operation M s ONLY Although this chamber has a waterproof design and was tested to verify its waterproof ness the reactivity of magnesium prevents its unprotected immersion in water It is recommended that a protective sheath be used if the chamber is to be in any contact with water Please refer to the Care of Exradin M1 and M2 Magnesium lonizati
9. discon nect the ionization chamber Service Notes a ed 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 bot tom on the shell tip and provide a small gap between the bottom of the cap and shell step To remove cap for mea surements either in lower energy beams or in a liquid phan tom merely pull on cap while again rotating cap clock wise Stem The standard stem configuration for all thimble chambers is a 1 3 cm OD black phenolic two piece stem with 10 1 and 12 7 cm segments They are threaded together and can be separated if desired Different stem configurations 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 cham ber when operating in a liquid phantom The cable con nector prevents complete removal of the stem In unscrew ing the stem from the base of the chamber the chamber must be gripped in the region between 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 Service Notes ee Stem A1SL A14SL and A16 ONLY The one piece Aluminum stem 0 64 cm OD 10 1
10. hamber is within the manufacturer s stated acceptable limits lf measured in the presence of background sources note that this signal will add to the leakage of the chamber 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 exposing the chamber to radiation This reading should be less than 0 1 of the final signal expected If it is not the leakage should be subtracted from the signal 8 Measure atmospheric temperature and pressure For 4 O General Operation asp gt gt zz well chambers measure the temperature in the well of the chamber 9 Insert the ion chamber and take at least 3 measure ments 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 sufficient 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 calibra tion factor consists of the electrometer calibration and the ionization chamber calibration factor 11 When all measurements are completed set bias voltage to 0 VDC turn off the electrometer and
11. lastic C552 M1 Magnesium T1 Shonka Tissue Equiv plastic A150 Slimline Miniature Shonka Thimble Chamber MODEL A1SL A1SL REF 92722 A 48 S 4 4 mm 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 cm 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 Spokas Thimble Chamber MODEL 2 A2 REF 92718 M2 REF 92719 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 cm 6 R nC 7 0 mm from tip of chamber 4 6 mm 11 5 mm 1 0 mm A2 Shonka Air Equiv plastic 0552 M2 Magnesium P2 Polystyrene Equiv plastic D400 T2 Shonka Tissue Equiv plastic A150 Farmer Type Chamber MODEL A12 21 6 mm 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 Co Buildup Cap A12 REF 92700 0 65 cm 5 R nC 12 9 mm from tip of chamber 1 0mm 7 1mm
12. on Chambers Tech Note located in the Products link on our website for additional information 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 Parts and Accessories eee REF Description 72122 A1 A14 Co 60 Cap 2 0 mm C552 72125 A1SL A14SL Co 60 Cap 2 0 mm C552 72123 T1 T14 Co 60 Cap 4 0 mm A150 72124 M1 Co 60 Cap 2 0 mm Magnesium 72126 A2 Co 60 Cap 2 0 mm C552 72129 T2 Co 60 Cap 4 0 mm A150 72128 P2 Co 60 Cap 4 0 mm D400 72124 M2 Co 60 Cap 2 0 mm Magnesium 72141 A16 Co 60 Cap 2 5 mm C552 72121 A12 A12S Co 60 cap 2 8 mm C552 72161 A12 4 MeV cap 10 5 mm Delrin 72159 A12 6 MeV cap 15 8 mm Delrin 72162 A12 10 MeV cap 25 7 mm Delrin 72163 A12 12 MeV cap 30 5 mm Delrin 72164 A12 15 MeV cap 37 4 mm Delrin 72160 A12 18 MeV cap 44 0 mm Delrin 72140 RSVP Phantom Adaptation for all Thimble chambers except SL s and A16 72169 RSVP Phantom Adaptation for A1SL A14SL and A16 only 72142 Gas Flow Provision must be requested at time of original chamber purchase except AISL A14SL and A16 Calibration _ eee As is standard practice for other ionization chambers it
13. our 24 months for ionization chambers and twelve 12 months for all other Standard Imaging Inc products from the date of original delivery to the purchaser or a distributor this product is warranted against functional defects in materials and workmanship provided it is properly operated under conditions of normal use and that repairs and replace ments are made in accordance herewith The foregoing warranty shall not apply if the product has been dissembled altered or repaired other than by Standard Imaging Inc or if the product has been subject to abuse misuse negligence or accident Standard Imaging s sole and exclusive obligation and the purchaser s sole and exclusive remedy under the above warranties are limited to repairing or replacing free of charge at Standard Imaging s option 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 12 or 24 month warranty period 3 which are returned to Standard Imaging promptly after discovery of the defect and 4 which are found to be defective upon Standard Imaging s examination Transportation charges are the buyer s responsibility This warranty extends to every part of the product except fuses batteries or glass breakage Standard Imaging Inc shall not be otherwise liable for any damages including but not limited to incidental damages con
14. sequential damages or special damages Repaired or replaced products are warranted 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 fitness 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 damages 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 for any warranty conditions unique to the product 16
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