NTNU
HSE
Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
1 of 7
Replaces
01.01.2006
1. Objective
The objective of this set of guidelines is to ensure safe organisation of the radiation
protection for all use of x-ray apparatus and electron microscopes at NTNU.
2. Scope
This set of guidelines applies to all units with open or closed x-ray apparatuses and
electron microscopes. Together with The Regulations on Radiation Protection and
the Use of Radiation, this set of guidelines governs the radiation protection for x-ray
apparatuses and electron microscopes at NTNU.
3. Responsibilities and authority
The line manager must oversee that the unit has a system for radiation protection
which ensures that using and handling the unit’s sources of radiation and its electron
microscopes is not associated with potential danger to the operators or their
surroundings. The line manager must also oversee that a person responsible for the
apparatus is appointed for each of the x-ray apparatuses and electron microscopes
owned by the unit.
The line manager must ensure that education/training in radiation protection related
to relevant sources at the unit is offered.
4. Definitions and abbreviations
X-radiation: The wavelength area ranging from 0.1 – 0.003 nm (energy 10 – 500 keV)
is the most frequently used part of the x-ray spectrum. X-radiation is normally
produced by using a solid substance to stop an electron beam.
X-ray apparatus: Used at NTNU for x-raying objects, structural determination and
 Open beam x-ray apparatus: x-ray apparatus where the beam is not enclosed.
Accidental exposure to the x-ray radiation may occur
 X-ray diffractometer: Closed cabinet with an x-ray tube that emits radiation up to 3
kW, typically 40 and 60 kV. Does not involve risk of human exposure
 X-ray cabinet: at NTNU: A closed cabinet containing an ex-ray tube and a
fluoroscopic screen emitting ionising radiation up to 160 kV
Electron microscope (EM): An instrument where a beam is sent from a filament,
forming x-rays when hitting an object. Primarily used for depicting objects and
elemental constitution. The beam is encapsulated
 SEM: scanning electron microscope, typical maximum output voltage 30 kV
 TEM: transmission electron microscope, typical range of maximum output voltage
100-300 kV
5. Safe use of x-ray apparatus and electron microscopes
5.1 Acquisition of x-ray apparatus and electron microscopes
Before acquisition the following must be done/clarified:
 Ownership (in cases of joint acquisition by several units)
 The owner must make a risk assessment (HMSRV3601E) before installation and
use
 In cases of joint acquisition/use (e.g. with SINTEF), who is responsible for HSE?
NTNU
HSE
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Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
2 of 7
Replaces
01.01.2006
Who will be responsible for the apparatus?
Who is the local radiation protection coordinator?
Is any particular competence required in order to use the apparatus? Does this
competence exist at the unit?
Who will take care of preventative maintenance? Service agreements?
Is any particular shielding required in relation to neighbouring rooms/activities?
Ensure that the system is supplied with Norwegian labelling
Contact the Technical Division if particular cleaning routines or ventilation
requirements apply, or if changes to buildings are required
Contact the Purchasing Section. Please find their checklist. Consider also
whether personal protective equipment and required shielding equipment needs
to be bought, and Norwegian labelling acquired
5.2 Installation and use of x-ray apparatus and electron microscopes
 Before x-ray apparatus/electron microscopes are installed and taken into use, a
risk assessment (HMSRV3601E) must be made of the system in relation to its
users, other personnel in the vicinity, the buildings, the environment (e.g. if
dangerous gases are used) etc. The assessment should be conducted in
consultation with the local radiation protection coordinator.
 Notify the local and central radiation protection officers of all new acquisitions,
relocation of sources, and disposal of x-ray apparatus or electron microscopes.
5.3 Organisation of the users
5.3.1 Persons responsible for the apparatus
Every x-ray apparatus/electron microscope must have someone from among the
academic staff who is responsible for the apparatus, and preferably also a substitute.
The person responsible for the apparatus has a general responsibility for the
apparatus, for radiation protection, and for ensuring that its users are provided with
knowledge and training in how to handle the relevant x-ray source. The person in
charge of the apparatus may delegate the training of operators, daily operation and
organisation of routine maintenance to operations engineers/technical staff.
The person responsible for the apparatus must evaluate whether potential users
have sufficient competence to function as independent users of the relevant sources
and provide documentation for this in the form ”Approval of unsupervised user of xray apparatus/electron microscopes at NTNU”. (HMSRV3602E)
5.3.2 Unsupervised user
Unsupervised users must have sufficient competence to make independent
evaluations in terms of safe use of the x-ray apparatus/electron microscope.
Sufficient competence implies apparatus-specific knowledge about starting-up
procedures, instrument settings, safety devices, shutting-down procedures,
emergency procedures if such apply, the contents of the information binder, any
completed measuring of radiation, etc.
NTNU
HSE
Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
3 of 7
Replaces
01.01.2006
5.3.3 Supervised use of open beam x-ray apparatus
Students attending laboratory courses and others who are going to use open beam
apparatus under qualified supervision must sign for having a basic understanding of
x-ray sources and radiation protection. This implies that they have studied the
relevant information on radiation and radiation protection in the HSE booklet of the
Faculty of Natural Sciences and Technology, as well as the regulations on radiation
protection in the HSE handbook for NTNU. The form ”Safety instructions for the TEM
laboratory at the Department of Physics” must be signed (available in the Department
of Physics). Signed forms must be stored in accordance with the department’s
internal routines.
5.3.4 Supervised use of electron microscopes and enclosed beam x-ray apparatus
The person in charge of an experiment/demonstration must ascertain that everyone
present has understood the risk factors associated with the x-ray apparatus/electron
microscope and will act accordingly. During demonstrations for special groups, e.g.
children, the following-up of safety measures is particularly important.
5.4 Technical measures designed to prevent exposure
Units that use x-ray apparatus/electron microscopes must implement and document
technical measures designed to prevent that anyone is exposed to ionising radiation
that exceeds the limits for safe exposure. The checklist in Appendix 1 is a tool that
may be used in this work.
5.4.1 Access to the laboratories
Access to rooms containing x-ray sources must be as restricted as possible, and
include only those who have a legitimate need to enter the room. The doors must be
locked when nobody is present. Restricted access to rooms containing electron
microscopes may be limited to after normal work hours if the room is under
supervision during normal work hours.
Certain instruments will be left with the radiation source continuously turned on. This
is in order to prolong the life of the radiation source, and because of long start-up
times. At NTNU this applies to certain electron microscopes and x-ray
diffractometers. Restricted access as described above will represent sufficient
security measures.
5.4.2 Starting up the source of radiation
According to § 14, section c in the Regulations on Radiation Protection and the Use
of Radiation it must not be possible to start up x-ray apparatus without a key or code.
Where knowledge of the correct starting-up procedure is required in order to
generate radiation, an application seeking exemption from this requirement may be
submitted to the NRPA. For such apparatuses information about starting-up
procedures must not be disclosed to unauthorised persons. For apparatuses with a
key function the key must be removed and kept out of reach of unauthorised persons
when the apparatus is not in use. Installing an electronic key requiring user name
and password to start up the apparatus is another option that may be considered.
NTNU
HSE
Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
4 of 7
Replaces
01.01.2006
5.4.3 Limiting the radiation
 Open beam paths must be shielded in order to prevent accidental access to the
beam path as well as reflected radiation (plexiglass, lead screens, lead curtain
etc.)
 Consider separate operating rooms where this is feasible
 Minimise the time spent next to the source
5.4.4 Storing sources that are not in use
Rooms for storing sources that are not in use must be locked off. If the room is under
supervision during ordinary work hours, it may be kept locked off only beyond these
hours.
5.4.5 Physical safeguarding of the x-ray apparatus
The unit must safeguard x-ray apparatus and x-ray sources against theft, sabotage,
fires and water damage.
5.5 Labelling and signposting
 A room-card and a standard radioactivity warning sign must be posted on all
doors leading to rooms containing x-ray apparatus. The room-card must provide
concise information in terms adapted to outsiders/non-experts (cleaning staff, fire
fighters etc.) about the dangers associated with the room, and the required
precautions. Classification according to § 20 in the Regulations on Radiation
Protection and the Use of Radiation [strålevernforskriften] of the workplace as a
“controlled area” or a “supervised area” must be stated on the room-card.
 The x-ray source on all types of x-ray apparatuses must be marked with the
standard warning sign for ionising radiation.
 An apparatus card (HMSRV3603E) should be posted on/beside each instrument.
 No sign containing the symbol for radioactivity should go up on doors leading to
rooms with electron microscopes.
The labelling must be in Norwegian, but corresponding information may be given in
other languages as needed.
5.6 Emergency preparedness
The unit must prepare a local emergency plan after conducting risk assessment of its
activities. As a minimum, this emergency plan should include:
 Internal and external procedures for notification/sounding of alarm
 The distribution of responsibilities
 Planned procedures for the handling of specific situations
 Procedures for identifying the extent of an accident/incident
 A description of measures that must be implemented in order to limit exposure to
radiation
 A description of relevant emergency equipment and where this is found
 Procedures for following up personnel and others involved in the episode
NTNU
HSE
Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
5 of 7
Replaces
01.01.2006
The local emergency plan must be coordinated with the Central emergency plan for
accidents involving sources of radiation at NTNU. It is important that people in the
unit are familiarised with the emergency plan.
5.6.1 Informing other personnel and others in the vicinity
Other persons performing work in the unit, but who are not connected to its academic
activities (cleaners, craftsmen etc.), must be informed about the most important
properties and dangers connected to the apparatus; cleaning procedures; the
significance of warning signs and warning lights (if any); contact information etc.
5.7. Documentation
5.7.1 Inventory of sources
All x-ray apparatuses and electron microscopes must be registered with the local and
central radiation protection coordinators. New acquisitions, as well as relocation and
disposal of apparatuses must be recorded.
5.7.2 Radiometry
Radiometry of the radiation dose received in the vicinity of the apparatus (not
including the actual beam) must be conducted as a routine at least once a year, after
routine maintenance1 and after significant alterations to the instrument set-up. Please
write down the results in the instrument log. The department must assess the risks
involved in different types of maintenance work and minor adjustments normally
undertaken in relation to these instruments, and implement internal routines for
radiation leakage inspections.
A radiation monitor adapted to the properties of the radiation must be used. X-ray
instruments with radiation energies lower than approximately 30 keV represent a
danger mainly to skin and eyes. It is therefore important to measure the surface dose
(H[0.07]). For TEMs (transmission electron microscopes), measurements must also
be made above the column. The central radiation protection coordinator in the HSE
Section can be contacted for this kind of measurements.
5.7.3 Dosimetry
According to the regulations, users of x-ray apparatus2 will normally be obliged to
wear a personal dosimeter, but exemptions can be made from this if the following
conditions are met:
 The effective radiation dose for a person is estimated to be less than 1 mSv/year,
based on dose readings, actual patterns of use, and no significant risk of
exposure near the direct beam.
 A check measurement to detect any leakage radiation is conducted annually, after
various types of maintenance work (see chapter 7.1 on radiation measurement)
and after significant alterations to the instrument set-up.
1
2
For electron microscopes an example of this is dismantling of the column.
Dosimetry is not relevant in relation to using electron microscopes.
NTNU
HSE
Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
6 of 7
Replaces
01.01.2006
In the Department of Physics the following additional requirements apply:
 All work involving an open-beam x-ray source that is switched must be entered
into a log, and the information must be stored in the department or NTNU’s
archives for 60 years. NB! Remember to specify on the documentation how long it
is to be kept for.
Regardless of the above, anyone who wants to use a suitable dosimeter must be
given the opportunity to do so. The local radiation protection will administer the
personnel dosimetry services.
Results of dosimetry measurements, as measured or estimated, must be conveyed
annually to the user in question, as well as to the central radiation protection
coordinator. NB! This information is personal, and to be handled according to § 5
letter a in the the act relating to public access to information [Offentlighetsloven].
The central radiation protection coordinator must ensure that the information is stored
in the HSE Section’s patient file system.
5.7.4 Log
Each x-ray apparatus/electron microscope must have a log into which is entered the
names of users, date, alternatively also duration, type of work, maintenance and
other information that must be entered into a log. Maintenance and significant
changes to the instrument set-up must also be entered into the log. The log/s must
be kept beside the apparatus. A back-up copy must be made annually of the activity
involving open-beam x-ray apparatus by the person responsible for each apparatus.
This back-up copy must be stored in the unit for 10 years. The unit must consider
whether equivalent procedures are also necessary for x-ray diffractometers/x-ray
cabinets and electron microscopes.
5.7.5 Information binder
Each laser apparatus must have an information binder (HMSRV3604E) in which as a
minimum requirement must be included the following documents:
 General information
- Name of the person responsible for the apparatus and his/her
substitute, and of the local radiation protection coordinator/s
- Vital data about the apparatus
- Instrument-specific documentation
- Assessment of risk factors
- References to (or copies of) data sheets, rules and regulations relating
to radiation protection, etc.
● Operating instructions
- Instructions for practical use of the apparatus, safety precautions, log
writing procedures, locking-up procedures, use of radiometer if relevant,
etc.
- For x-ray apparatus: If a special starting-up procedure is in the place of
a key lock, the starting-up procedure must be out of the generally
available instructions 
NTNU
HSE

Safe use of x-ray
apparatus and electron
microscopes
Prepared by
The HSE
section
Approved by
The Rector
Number
Date
HMSR-36
01.12.2006
Page
7 of 7
Replaces
01.01.2006
Emergency procedures
- Instructions may be posted locally and/or distributed to others (e.g.
caretaker and cleaners) as required. It must be considered whether
English versions of documents are needed.
6. References
Forskrift om strålevern og bruk av stråling (strålevernforskriften)
Statens stråleverns hefte 8: "Persondosimetri for yrkeseksponerte"
Central preparedness plan for accidents involving sources of radiation at NTNU
HMSR32E Responsibilities and tasks within radiation protection
HMSR26E Risk assessment
HMSR27E Room-cards
HMSRV3601E Checklist for risk assessment before x-ray apparatus and electron
microscopes are taken into use (HMSRV3601E)
HMSRV3602 Authorisation of unsupervised use of x-ray apparatuses/electron
microscopes at NTNU
HMRSV3603E Instrument car
HMSRV3604 Specification of contents that should go into an information binder
HSE booklet of the Faculty of Natural Sciences and Technology, chapter 5.6.12:
Radiation protection [NT-fakultetets HMS-hefte, kap. 5.6.12 Strålevern]