Fluke Biomedical 37-705 - Manual (Page 30)

Nuclear Associates 37-705
Operators Manual
3-2
Detector configuration
Flatness/Symmetry One central axis
(Horizontal orientation) Four - orthogonally positioned at 8 cm off central axis in the transverse
and radial planes.
Off-axis detectors are positioned at 80% of field size for flatness and
symmetry measurements.
Energy constancy Detector depth positions: 4.5, 12.5, 20.5 cm
(Vertical orientation)
Interface Cable 50 ft (15 m) P/N 37-705-7300
Build-up 1.9 cm acrylic (2.3 g/cm 2 )
Size 9.85 (w) x 9.85 (d) x 1.5 in (h) (25 x 25 x 3.8 cm)
Weight 5.25 lbs (11.6 kg)
3.3 Connection to the VeriDose V
Connect the VeriDose QC Phantom cable to the phantom and the VeriDose V as indicated:
Channel 1 Central axis Yellow
Channel 2 -X Red
Channel 3 +X Green
Channel 4 -Y Blue
Channel 5 +Y White
3.4 Setup
Refer to the Setup Mode
-
QA Phantom section of the manual for detailed instructions regarding setup
parameters for the VeriDose QC Phantom.
3.5 Calibration
It is the responsibility of the user to calibrate the VeriDose system. It is recommended that the VeriDose
QC Phantom be calibrated under the conditions that represent normal daily use. Since the calibration
process will associate a particular detector to a specific channel on the VeriDose V, it is necessary to
connect the device properly (as indicated in the Connecting to the VeriDose V section) for the calibration
process as well as for subsequent measurements.
Reference the VeriDose Calibrate Modes section of the manual for a complete description of the calibra-
tion functions. Two methods of calibrating the VeriDose QC Phantom are described below:
Method 1
Calibrate all 5 detectors (channels) individually, centering each detector on the central axis at 100 cm
SSD. Place build-up material equal to or greater than Dmax depth over the detector. Use a small field
size of 5 x 5 cm and irradiate to a known calibration dose. Repeated exposures are recommended for
dose averaging, with a maximum cumulative dose of less than 1000 cGy.
Verify the calibration process by setting the recommended 20 x 20 cm field size and aligning the QC
Phantom's central diode with the central ray. Place calibration build-up over the entire phantom. Beam