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Home My WebLink AboutConcrete testing MRIC PROJECT#1509 Sun-rt 10 1 FINAL SHIELDING EFFECTIVENESS TEST REPORT FOR THE GENERAL ELECTRIC MEDICAL SYSTEMS, INC. NEW RF SHIELD LOCATED AT THE CONGRESS MEDICAL ASSOCIATES MRI FACILITY ARCADIA, CA PREPARED FOR MRI CORPORATION 3554 BUSINESS PARK DRIVE, STE. B COSTA MESA, CA 92626 TR#1953-1406 PREPARED ON 22 JUNE 2014 BY JOHN G. LINDENMEYER, EMC CONSULTING MRIC PROJECT #1509 JOHN G. LINDENMEYER, EMC CONSULTING 22 June 2014 TR41953-1406 FINAL SHIELDING EFFECTIVENESS TEST REPORT This document reports the results of the final shielding effectiveness (SE) measurements of the new RF shield, located at the Congress Medical Associates MRI Facility, Arcadia, CA. MRI Corporation (MRIC) requested these measurements to determine the status of the new shield, for the GE 1.5 Tesla magnet system. Mr. Bill Lindenmeyer, EMC Technician, performed the SE measurements on the new RF shield, hereinafter referred to as the shield, on 20 May 2014. The test results presented in Table I, show that all of the test positions, around the shield, met the GE RF attenuation requirements (SE) of at least 100 dB, when tested at 100 MHz, 63.86 MHz, and 30 MHz. The test positions measured are identified on Page 2 of the data sheets provided in Attachment 1 to this document. Table I. Shielding Effectiveness Test Results Final Shielding Effectiveness Measurement Datafor the New RE Shield in the Congress Medical Associates MRI Facility,Arcadia, CA,for a GE 1.5 Tesla Magnet System(20 May 2014) Freq-`C=a 100 MHz 63.S6`. -x 30 mi--Z Test Reference L eve! 1 105 N mum 105 Ncw:mu:n 105 NEaimt I.ocsaon d3 S:?Nase Level Letkase Calnslated Leakage Calculated Lea32ge Calculated Description _ Level SE Lete1 L, SE Leve SE A !Door-center 5 100 0 >105 0 >105 B ISGindou'-Left 5 100 0 >105 0 >105 C 1e ow-RiWit 5 100 0 >105 0 >105 + D Outside Wall-Lett 0 >105 0 >195 0 >105 i + E Outside Wall-Center 10 95 0 >105 0 >105 1 F Outside Wall-Right 10 95 0 >105 0 >105 0 Back Wall-Left i 5 100 0 >105 0 >195 H 1SYk Wall-Center 1 0 >105 0 >105 0 >105 1 Back Wall-Rich: 0 >105 0 >105 0 >105 S Inside Wall-L eft S 100 0 >105 0 >105 K !Pen Panel 30 1 75 1 10 ■ 35 1 10 1 95 11 JIrsideWall-Risht 10 1 95 1 0 >105 0 >105 I Note: The calculated shielding effectiveness of a test location is the reference level minus the measured leakage level.in dB above the spectrum analyzer noise level. Shielding effectivenessisin dB. All.tlx measured SE levels that did not meet the GE requirements of 100 rB or greater;when tested at 100 .V^:a. 63.S6 4 4z, and 30 Nfra,axe boxed 1 MRIC PROJECT#1509 TEST RESULTS The shield was grounded for system operation and filter safety. An analysis of the E-field measurement data indicated that all of the test positions met the GE E-field SE requirement of 100 dB, or greater, when tested at 100 MHz, 63.86 MHz, and 30 MHz. A minimum SE of 75 dB was measured at the pen panel test position for the 100 MHz test frequency. The remaining test positions measured between 95 dB and>105 dB at this frequency. A minimum SE of 95 dB was measured at the pen panel test position for the 63.86 MHz test frequency. The remaining test positions measured>105 dB at this frequency. A minimum SE of 95 dB was measured at the pen panel test position for the 30 MHz test frequency. The remaining test positions measured >105 dB at this frequency. For this report, the GE pen panel was installed. This configuration never meets the GE requirements, and GE personnel always accept the test results. No other leaks were found. SCOPE E-field shielding effectiveness measurements were made on the shield at 100 MHz, 63.86 MHz, and 30 MHz to determine if the shield, with its necessary openings, met the GE E- field specification limits of 100 dB, or greater, over the frequency range from 30 MHz to 100 MHz. Those items evaluated were: • The door - center • The window - left • The window - right • The outside wall - three locations • The back wall - three locations • The inside wall -two locations • The pen panel Mr. Bill Lindenmeyer, EMC Technician, performed the SE measurements on 20 May 2014. This was a new shield. The magnet was in place and the magnet hatch was sealed. The pen panel was installed, and connected (compressor power only). The power line filters were installed, but not connected to facility power. The spectrum analyzer was operated on battery for the test. 2 MRIC PROJECT#1509 MEASUREMENT PROCEDURES E-field measurements were made on the shield, using MIL-STD-285 as a guide. For the calibration measurements, the transmit and receive antennas were placed 25 inches apart, in an open area of the facility. The rod antenna heights were adjusted so that they were positioned in the approximate vertical center of the shield, which placed the ground planes at 32 inches above the floor of the shield. An output frequency of 100 MHz was selected at the signal generator for transmit and the power amplifier was turned on. The signal, at 100 MHz, was identified on the spectrum analyzer and the input attenuators to the spectrum analyzer were adjusted until the signal at 100 MHz was below the spectrum analyzer noise level. The sum of the attenuation of the attenuators was recorded as the reference level (REF. LEVEL)on the data sheets. This procedure was repeated for the 63.86 MHz and 30 MHz test frequencies. For the SE measurement, the receive antenna was moved into the shield and the door was closed. The receive antenna was placed approximately 11 inches from the personnel door center test position, at Test Position A. The test positions are identified on page 2 of the data sheets. The transmit antenna was positioned at Test Position A, on the outside of the shield, approximately 12 inches from the door. These distances, plus the thickness of the door, positioned the antennas approximately 25 inches apart, for the test. The signal generator and the power amplifier were turned on and the signal level, measured at 100 MHz, was recorded on the data sheets as the measured leakage level (MSUR). E-field SE was calculated by subtracting the measured leakage level from the reference level. The difference was recorded as the minimum calculated SE (SE) on the data sheets. The antennas were then moved to the observation window test position, at Test Position B, and the measurements and calculations were repeated. This procedure was repeated until all of the test positions were measured at all three frequencies. Actual SE values for each test position are listed on the data sheets presented in Attachment 1. 3 TR# 1953—22 June 2014 ATTACHMENT 1 FINAL SHIELDING EFFECTIVENESS TEST RAW DATA SHEETS FOR THE GENERAL ELECTRIC MEDICAL SYSTEMS, INC. NEW RF SHIELD LOCATED AT THE CONGRESS MEDICAL ASSOCIATES MRI FACILITY ARCADIA, CA TR# 1953 —22 June 2014 PAGE 1 OF 4 RAW DATA SHEETS MRI SHIELD NAME 'n-/L21<�--S 1 Xr,-b 7CA-c. 4c s oc 1477,1 LOCATION k L. C. /A- A (—A MEDICAL SYSTEMS 6-7., MAGNET SIZE /" -3 NEW SHIELD REMODEL FIND&FIX PRE-TEST FINAL TEST SHIELD CONTRACTOR ,4g /C, TEST ONLY(NO REPORT) INCLUDE REPORT t r✓c>A eel i"/A7-74a TEST ENGINEER- Bill Lindenmeyer , TEST DATE 5--- 2) 1 y TR# 1953 —22 June 2014 PAGE 2 OF 4 SETUPS FOR SHIELDING EFFECTIVENES MEASUREMENTS TEST SETUP AND TEST ANTENNA POSITIONING FOR CALIBRATION MEASUREMENTS TRANSMITTER ANTENNAS RECEIVER SIGNAL RF IJGL 1 i I JGL 2 /� SPECTRUM GENERATOR AMP 25 INCHES , V ANALY ER ATTENUATOR ROOM CONFIGURATION AND TEST POSITIONS(1) �r �� J) a- E--- SHIELD J MAGNET ,.1 n >�fh C tom. r,.1 � _. S Z �� A c I f f l k)<.)11).6- CiVs ),.1S r pi( (1) IDENTIFY ALL TEST POSITIONS: DOORS&WINDOWS,FILTER PANELS,WAVEGUIDES,AND AIR VENTALATION PANELS. TEST ENGINEER-Bill Lindenmeyer �! s- TEST DATE S` 2 0. 1 TR# 1953 —22 June 2014 PAGE 3 OF 4 PROCEDURES FOR SHIELDING EFFECTIVENESS MEASUREMENTS CHECK WHEN COMPLETED 1. SETUP AND TURN ON TEST EQUIPMENT 2. E FIELD CALIBRATION MEASUREMENTS AA) MHZ. '3'S'1a MHZ, -5'C) MHZ. 3. E FIELD SE MEASUREMENTS MO MHZ, . odr'MHZ, 36 _MHZ. 4. REVIEW DATA SHEETS AND SECURE TEST EQUIPMENT -�y STATUS OF$WELD YES /NO CONSTRUCTION COMPLETE / MAGNET INSTALLED MAGNET HATCH SEALED j� PEN PANEL INSTALLED PEN PANEL CONNECTED C,DM°,26SCc rot.ic-1. , , WALL FINISHED / CEILING INSTALLED / POWER LINE FILTERS INSTALLED POWER LINE FILTERS CONNECTED TO FACILITY POWER / SCAN ROOM RECEPTACLES USED / ,,, LIGHTS CONNECTED TO FACILITY POWER AND IN USE / DOOR SEAL OPERATIONAL i FIRE SPRINKLERS INSTALLED MEDICAL GAS LINES INSTALLED CRYOGEN VENT INSTALLED-CONNECTED ! TEST ENGINEER-Bill Lindenmeyer // TEST DATE S` ZG- TR# 1953 —22 June 2014 PAGE 4 OF 4 E FIELD MEASUREMENT DATA FREQ-MHZ /00 MHZ 654 MHZ 7e2 MHZ REF. LEVEL /US- /o S— /0 D$/SA NOISE MSUR SE MSUR SE MSUR SE TEST LOCATION A 1 oa.. 5- /oo ,6 !U s— •' .16.1 B - LA)/ �, 7 /0 -6-- icy , S-r C -u1,,,1baw f,,. >/Qs '4 ',o,r E OtA�4>4,— /0 �i i— 6s- >rur--- 6, I, fo, F /0 9,' -,_-. >-/0:r t" >t 0r-- G 6— /00 ,.-- `>tor 6'' >104-- H Qa-�.� I tY >101-' -{S-" >(O 5-- ✓ >iii(" K - c•-y.), P, cz 30 76-'- /eP 9s /o is — L- „mss iac` +^14"1/4A- i0 9S-" . - >1vS" 4- ' icj.-- M N 0 (1) IDENTIFIED TEST POSITIONS PROM PAGE 2 TEST ENGINEER-Bill Lindenmeyer TEST DATE 57 241:i r