Bruker e-scan

Question 1

e-scan

Answer 1

It is a bench top EPR (Electron Paramagnetic Resonance) spectrometer dedicated to the evaluation of absorbed dose in alanine dosimeters (either film of pellet). The EPR spectrometer works by measuring the energy level transitions of free radicals at a specific resonant frequency within a variable magnetic field.

Question 2

free-radicals

Answer 2

unpaired electrons

Question 3

stray fields

Answer 3

Rad. 127mm-200mm=5mT
Rad. 162mm-330mm=1mT
Rad. 167mm-370mm=0.7mT
Rad. 173mm-410mm=0.5mT

Question 4

basic user

Answer 4

basic operator

Question 5

operator user

Answer 5

general purpose operator

Question 6

o++ user

Answer 6

more advanced operator

Question 7

qcm user

Answer 7

quality control manager

Question 8

administrator user

Answer 8

system administrator, full access to all features

Question 9

pcn

Answer 9

process control number

Question 10

Import Bridge Calibration

Answer 10

C:\Bruker\e-scan\Dosimetry\Acquisition\SYSCAL

Question 11

Spectrum Parameters

Answer 11

parameters for dosimeter inserts

Question 12

.mdb

Answer 12

Microsoft Access database file

Question 13

backup file

Answer 13

when 800MB is reached

Question 14

Alanine

Answer 14

is one of several compounds called “amino acids”. Amino acids comprise the building blocks for biological molecules known as proteins. When the alanine is subjected to ionizing radiation it forms a very stable free radical. The alanine free radical produces an EPR signal that is dose dependent, yet is independent of the dose rate, energy type, and is relatively insensitive to temperature and humidity. Thus, alanine dosimetry is equally suited to Gamma, E-beam, or X-ray irradiation
facilities.

Question 15

Dosimeter insert

Answer 15

contains a carefully measured quantity of a proprietary
Bruker reference marker that also produces an EPR signal. Every scan performed by the e-scan will simultaneously measure the alanine free radical (in an irradiated dosimeter) and the internal reference marker of the dosimeter insert. The intensity value that is correlated with dose is the ratio of the alanine EPR signal to that of the reference marker’s EPR signal.

Question 16

Irradiation Dose

Answer 16

is determined from a ratio of EPR intensities (alanine free radical / Internal reference marker).

Question 17

Validation

Answer 17

Validation is a high-level review to determine the conformity of a system, process or product to internally established standards and the appropriateness
of these standards.

Question 18

Self Test

Answer 18

self test is designed to check your e-scan’s various hardware components for proper function.

Question 19

Signal-to-Noise

Answer 19

is designed to assure the sensitivity of your e-scan is

adequate for making alanine dosimeter measurements The signal to noise ratio should be greater than 100:1.

Question 20

Repeatability Test

Answer 20

The repeatability test provides a measure of how consistent the e-scan is at reading the dose from a dosimeter. The test will measure the same dosimeter
100 times and should yield an RSD (relative standard deviation) of < 0.5%.

Question 21

Reproducibility Test

Answer 21

The reproducibility test measures the consistency of the e-scan when certain changes and interruptions are made during a series of measurements. The test
is nearly identical to the repeatability test and uses the same dosimeter (i.e., 50 kGy film or tapetab). However, during the reproducibility test you will measure the dosimeter only 25 times. (removing and re-inserting either the dosimeter or the dosimeter insert throughout the test.) The reproducibility test should yield an RSD of < 1.0%.

Question 22

Dosimeter Test

Answer 22

response of a dosimeter over a series of measurements using

Question 23

Calibration

Answer 23

To make a meaningful dose assessment the dosimeter measurements need to be compared with measurements made using certified dosimeters of known dose. This is achieved by performing the calibration routine which creates a calibration curve and corresponding fit coefficients from measurements made with a set of dosimeters with known certified dose.

Question 24

Amino Acids

Answer 24

Amino acids comprise the building blocks for biological molecules known as proteins.

Question 25

Bruker Internal Reference Standard

Answer 25

is a stable paramagnetic substance that will not change in absolute EPR intensity.