XRay Diffraction Training

8/7/2019 XRay Diffraction Training

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Produced when highspeed electron is sloweddown and/or stopped

Present an externalhazard. Can be reduced

by; Time Distance Shielding Engineered controls

(interlocks) Monitoring (GM Meter)

Administrative controls(Standard operatingprocedures)


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"Analytical x-ray machine" is A general term which refers to instruments that produce x-rays for

the purpose of analyzing materials or structures such as x-raydiffractometers (XRDs)and certain spectrometers (x-rayphotoelectron spectrometers).

To comply with State and Federal law, instruments not

normally considered to be analytical x-ray machines,such particle accelerators, can also be classified assuch. These instruments are capable of producing x-rays as a by-product of their function.

Specific hazards of analytical x-ray equipment caninclude: Exposure to an intense, localized primary x-ray beam Exposure to diffracted and/or scattered portions of the primaryx-ray beam (includes x-ray leakage)

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Accessible area have exposure rates not exceeding2 mR/hr (any area outside of the barrier or shieldroutinely occupied by personnel).

Maintain a log book of major changes to thesystem shielding, enclosures, and configurations.

Engineered protection system shall be maintained Failsafe interlocks on removable protective barriers Exposure rate below 2 mR/hr at 5 cm form any surface

Key control on the production of x-rays

A console power on indicator (must be operational andused) Warning light adequate to warn anyone present in the room

that x-rays are being produced.


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1. Primary Beam

2. Scattered Radiation

3. Leakage


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Cu

50 x (40) x (20) 29 = 279 R/sec(7.5)2 74

Mo

50 x (36) x (20) 42 = 363 R/sec(7.5)2 74

Ag

50 x (40) x (20) 47 = 452 R/sec(7.5)2 74

Cu

50 x (50) x (20) 74 = 889 R/sec(7.5)2 74

Exposure Rate:

50 x (kV) x (mA) Z = R/sec(cm)2 74

Characteristic Intensity:

Proportional to: (kVp - kVc)1.6


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Fingers are at risk. Significant injuries

have occurred withdiffraction x-rays.

Large exposuresmay occur.

Skin and eyes mayreceive exposures.


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1. Primary Beam

The critical radiation exposure problem with analytical X-ray equipment is the primary

beam. Exposure to the primary beam can cause localized acute exposure.

Consequently, the analytical operator must never intentionally place any part of their

body in the primary beam. Typically, these beams are relatively soft X-rays resultingin maximal energy deposition in epithelial tissues. Erythema or reddening of the skin

can occur when skin is acutely exposed to 300 R (much less than a second). Radiation

burns may occur from longer exposures.

2. Scattered Radiation

When the primary beam intersects a material such as a sample or elements of the X-ray

unit including the beam stop, some of the radiation is scattered out of the primarybeam. While these radiation fields are considerable less intense than the primary

beam, they still represent a potential hazard. Scattered radiation fields can be

measured by the analytical operators with a survey meter.

3. Leakage

Some radiation may leak around the rube housing structure. State law requires that

source housing construction shall be that when all the shutters are closed the leakageradiation must not exceed that of radiation limits for the general public.


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Poor equipment configuration Ex. Unused beam ports not covered

Manipulation of equipment when energized Adjustment of samples or alignment of cameras

when x-ray beam is on Equipment failure

Shutter failure

Warning light failure

Inadequate training or violation ofprocedure Incorrect use of equipment

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Know location and/or presence of allprimary and diffracted beams AT ALL TIMES Provide and inspect shielding

Do not perform maintenance (without

confirming that the tube is not energized) Perform check of safety devices at least once

per month

Survey unit whenever moved or

reconfigured. DONT PUT YOUR BODY PARTS IN THEBEAM!!

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If an exposure is suspected, do the following:

1. Report all potential exposures of this kindimmediately to your supervisor and/or person

responsible for the analytical unit.

2. The supervisor in turn needs to immediately notifythe Radiation Safety Officer so that evaluation,

corrective action and if necessary, medical

evaluation can be initiated.


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Analytical x-ray machines are regulated atthe state level by the New York StateDepartment of Health

Regulations governing x-ray machines and

other radiation producing machines can befound in NYS Sanitary Code 16

Federal Regulations are found in 29 CFRSubchapter J.

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Engineering Controls Visible indication ofenergized beam (light)

Visible indication ofopen shutter (light)

Safety devices testedand logged at leastmonthly

Primary beam shouldbe terminated

Interlocks, devices toprevent exposure topersonnel

AdministrativeControls Labels/signs Info on radiation

hazards, safe working

practices, effects ofradiation exposuremust be available nearunit

Know how to report

overexposure State/Federal Notice

to Employees

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Authorized by theRadiation Safety Officer

Ensures that onlyqualified individualsuse the equipment

Maintains theequipment incompliance with safetyrequirements


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Used to establishcontrols overhazards

Informs workersof conditions andtechniques withwork

Workers areresponsible tofollow procedures

Slide 17


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Time

Distance

Shielding


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Devices Interlocks

Key control

Shielding

Procedures Operating

instructions

Training Surveys

Exposure monitoring


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Interlocks dont work.

Radiation is observedduring surveys.

Unqualified peopleoperating the system.

Redness of the skin,normally to the hand.

Warning light is notoperational.


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Perform the pre andpost operationalchecks.

Record the results. Make sure warning

lights are working.

Wear your

dosimeter. Instruments record

low readings.


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Only Trained personnel shall be permitted to operate an analytical unit.

Be familiar with the procedure to be carried out.

Never expose any part of your body to the primary beam.

Turn the X-ray beam OFF before attempting to make any changes to the

experimental set-up (except for beam alignment) While the beam is on DO NOT attempt to handle, manipulate or adjust

any object (sample, sample holder, collimator, etc.) which is in the direct

beam path (except for beam alignment procedures).

Examine the system carefully for any system modifications or

irregularities. Follow the operating procedures carefully. DO NOT take short cuts!

Never leave the energized system unattended in an area where access in

not controlled.


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Survey the area frequently to evaluate scatter and leakage radiation

fields.

Never remove auxiliary shielding without authorization from the owner

of the analytical equipment or Radiation Safety Officer.

Never bypass safety circuits, such as interlocks.

Report all unusual occurrences to the owner of the analytical unit for

possible corrective actions.

Only authorized, trained individuals as specified by the units owner and

the Radiation Safety Office may repair, align or make modifications to

the X-ray apparatus.


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If you dont use it,it will not provideuseful information.

Wear it properly.

Dont wear anotherpersons film badge.

If you needadditional devices,contact the RSO.


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See handout - USB policy Responsibilities

Open and closed beam XRD systems

Also review article 10 Principles and 10Commandments of Radiation Protection

See handout on definitions

XRay Diffraction Training

Documents

Transcript of XRay Diffraction Training