Radiation Safety Training

Research & Analytical Machines

Washington State University Radiation Safety Office

Analytical X-ray Machines

These machines use a high intensity radiation beam for determining microstructure and elemental composition of materials. These machines include Xray diffraction (XRD), X-ray fluorescence (XRF) & X-ray crystallography (XRC) units.

RADIATION MACHINES AT WSU Used in Research

 Flash X-ray Unit  Analytical X-ray Units-XRC, XRD, XRF  Cabinet X-ray Unit  High Energy Cabinet CT Unit  Proton/Deuteron Accelerator

What are X-Rays?

 X-rays are a form of electromagnetic radiation which arises as electrons are deflected from their original paths or inner orbital electrons change their orbital levels around the atomic nucleus

X-ray Production.

 There are two different atomic processes that can produce x-ray photons.  They are Bremsstrahlung, and K Shell Knockout.

Bremsstrahlung

 "Bremsstrahlung" means "braking radiation" and is retained from the original German to describe the radiation which is emitted when electrons are decelerated or "braked" when they are fired at a metal target. Accelerated charges give off electromagnetic radiation, and when the energy of the bombarding electrons is high enough, that radiation is in the x-ray region of the electromagnetic spectrum.

K Shell Knockout

 Characteristic x-rays are emitted from heavy elements when their electrons make transitions between the lower atomic energy levels. The characteristic x-rays emission occur when vacancies are produced in the n=1 or K-shell of the atom and electrons drop down from above to fill the gap.

Basic methods in which x-rays interact with matter

Photoelectric Effect

occurs when photons interact with matter with resulting ejection of electrons from the matter.

Compton Scattering

occurs when the incident x ray photon ejects a electron from an atom and an x-ray photon of lower energy is scattered from the atom.

Pair production

can occur when the x-ray photon energy is greater than 1.02 MeV, when an electron and positron are created with the annihilation of the x-ray photon.

Definitions

kVp

- (kilovolts) - peak operating voltage

mA

(milliamps) - tube operating current

Exposure Period

- duration the beam is "ON”

Regulatory and Compliance Aspects of Radiation Machine Use.

First

• An application is required for all Authorized Users (Principle Investigators) and for each

machine.

Second Required Postings

(WAC 246-228-030) Performed by the RSO

The following sticker must be on all doors entering radiation facility

Required Postings (cont.)

 The following must be on the Radiation Machine

"Caution X-Rays, This Equipment Produces X-Rays When Energized"

Or

Required Postings Or (Continued)

-THIS EQUIPMENT PRODUCES WHEN RADIATION WHEN ENERGIZED CAUTION TO BE OPERATED ONLY BY RADIATION QUALIFIED PERSONNEL 

NOTICE: IF THIS EQUIPMENT IS MOVED OR MODIFIED, NOTIFY:

 WSU RADIATION SAFETY OFFICE (509) 335-8916 

BEFORE ENERGIZING THE X-RAY TUBE

Required Postings (Continued)

 On analytical X-ray Machines at the Source or Tube Housing  In the room near the machine 1. "Notice to Employees" (DOH RHF-3) 2. "Emergency Procedures"

The Radiation Safety Office Conducts Periodic Inspections of Radiation Machines

Your Inspection Checklist.



User Training Logs (WAC 246-228-050)

•  Machine Specific Training Documentation must be located near the machine and It must contain a: ● List of Approved Radiation Machine Users (WAC 246-228-050) ● The "Certification of Radiation Machine Specific Training" signed by the Authorized Machine User.

And a Written Description of the Training (outline or syllabus)

Inspection Checklist Cont.



The Operating Procedures Must Be:

(WAC 246-228-040) ● Readily available; pertinent excerpts may be posted.

● With a Copy on file at the RSO

Inspection Checklist Cont.



You Must Maintain a Machine Use Log

(entries must be dated & Initialed) and contain.

 Parameters Used (mA, kVP)  Date and Time  Machine Operator  Description of item being Radiographed  Exposure period - duration the beam is "ON“ 

And a Maintenance Log

(entries must be dated & Initialed)  Document Routine maintenance and  Non-Routine, Malfunction or problem and its resolution

Your Inspection Checklist Recap:

Postings (WAC 246-228-030)

 On the Door –X-Ray Producing Equipment  On the Machine – Caution X-Rays  In the Room – Notice to Employees and  Radiation Machine Approval Sheet

The Operating Procedures for the machine,

(WAC 246 228-040)  Should be Readily Available  And On File at the RSO

You Must Give Prior Notification To The RSO

 To purchase,  relocate,  transfer  or surplus  any radiation machine, you must coordinate in advance with the RSO to ensure a rapid and compliant effort.

RSO

Machine surveys by manufacturers and service/repair organizations must be documented:

 After installation and servicing with copies to the RSO.

If an X-ray machine requires repairs or servicing then the RSO must be notified prior to putting the unit back in service. Radiation surveys may be necessary to ensure that safety items such as shielding are reinstalled correctly.

INACTIVE RADIATION MACHINES

 RSO is required to maintain control of all radiation machines on campus including those that are inactive.  Contact the RSO if you are going to take out of service or reactivate any radiation machine.

Safety Devices

Policy on overriding interlocks or other safety devices

 "If any safety device (interlocks) is overridden or removed for any reason, then the RSO must be informed in writing (e-mail is acceptable) and in advance. The user must receive written (e mail is acceptable) approval from the RSO allowing this temporary situation. The RSO needs notification 24 hours in advance to react to such requests.” The information required is a description of what will be overridden and the expected duration that the safety device will be overridden.

Safety Devices (continued)

 Record of interlock checks (As Appropriate) (WAC-246 228-020) ● These checks must be performed routinely and documented.

 Fail safe test of system lights – document the test ● "X-ray On" light ● "Shutter Open" light

Test Time!

 Follow this link to the test. https://myresearch.wsu.edu

 Use your WSU user name and password to sign in.

 Click on the training tab.

 Then click on the available training tab  Find the radiation safety training Machines course, in the OR section, click on it and take the test.