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Last update: April 2013. Do not hesitate to validate the information if doubt on their validity.
 Access to LHC area
How the danger of a underground area of the LHC is determined?
RP technician monitor the work area and the access path. Depending on the level of radiation measured, the area is classified differently and actions are taken to ensure radiation safety of personnel involved (EPC). The risk zone of the LHC or other accelerator is defined by its classification: this is established following a mapping of radiation levels associated with a series smear which is used to certify the absence of contamination. In the case of a survey before a technical stop, all sectors are controlled and classified radiologically; this is why the area can then remain open. Given the radiological risks in the radiological controlled areas of simple (LHC machine and experiments), it was accepted that the personal dosimeter (RADOS DIS 1) could serve as a dosimeter without alarm.
How to know the classification of the LHC areas?
Real-time classification of areas at the LHC is available in real time here .web.
Is it normal to intervene in the LHC without RP at his side?
Yes, if the proposed area has been controlled (passing an RP technician). The veto radiation acquired from the effective operation of the LHC can be raised only on this condition, making access possible.
Is it normal to intervene in the LHC with RP at his side during a first passage control?
Yes, the RP technician will arrange for abnormal measures met to put the personnel involved in safety. This case is normal because the person requesting the intervention knows exactly where and / or equipment on which it has to work. RP can therefore carry out such measures at the workplace and make a proper risk assessment. If RP measuring radiation levels requiring a different classification of the area, with a complementary dosimetry for the intervener person, then RP will provide it and indicate precisely the places to avoid.
The area is classified as "Simple Controlled Area", can I intervene without RP my side?
Yes, once the survey and the classification established by RP, and as part of a simple controlled area that does not need to keep a veto; beyond the simple controlled area the veto will remain and PR will provide a dosimeter for this classification. A DIMR (radiological environment intervention record, required upon limited living area classification) will then be written with RP + RSO + Interventant.
At what time should I use an operational dosimeter (real time information)?
From the moment the area is a "Limited Stay Area", or beyond.
Is my personal dosimeter can replace an operational dosimeter?
No, the dosimeter alerts in real time from abnormal exposure and therefore allows to move away from a potentially radiating source. Preselection by RP alarm in dose and dose rate on all operational dosimeters (2 mSv and 2 mSv / h in 2010-06)
The area is a "Limited Stay Area", but there is not enough dosimeter for all. Then I go in, counting the one wearing my colleague?
No, the instruction is not to enter the area in question.
When the intervention is it potentially dangerous?
Never, since the arrangements are always tailored to the risk encounter. A classified area "Monitored Zone" is not dangerous (personal dosimeter is simply required). In addition, a potential risk exists and instructions will then be adapted (dosimeter, time limited intervention, zoning ...).
On what basis the RP technician he bases his judgment as to the dangerousness of the environment?
RP technician has undergone expert training in radiation protection, and he knows the mechanisms related to radioactivity and its dissemination. It can measure and interpret the environment for its own safety and the safety of the personnel involved.
A fault occurs on a converter in a little area away from the area covered by the initial survey of RP. Can I go quickly take a look?
Not if the area has not been controlled by RP.
What simple precautions should I take action?
Keep away from magnets, and generally of the vacuum chamber. Do not put your hands to faces (especially the mouth) for hygiene issues primarily because the risk of contamination does not exist with the monitored area classification. Wash hands and control output by measuring hand-foot. Do not unnecessarily stay in the tunnel near or activated equipment (buffer zones). In the tunnel, respect the traffic signs RP.
Is that I can use the Pico Wall for measuring contamination standard measure hand-foot?
No, the Pico Wall lacks the necessary sensitivity to this type of control. (Camera suitable for hardware activation measures only).
Dust in the LHC is it radioactive?
RP measures by "smear" control the activation or not of the dust. These controls are not systematic if activation measures are low. contamination risk does not exist with the monitored area classification. If, following the smear, the presence of contamination in the LHC tunnel proved then the classification will be changed immediately and become the minimum controlled Zone Residence Time Limited.
Personal et Operational Dosimeter
What are the differences with a personnal and operational dosimeter?
The operationnal dosimeter indicates REALTIME: a cumulative dose displayed on a digital screen, and provides information on the dose rate (beep), which is not the case of the personal dosimeter searchable "OFF LINE" on a terminal RADOS.
A operationnal dosimeter, how to use?
When you enter a Controlled area, you need to insert the DMC in the drive, enter (keypad) your IMPACT activity code and press "ENTER", check that your DMC is on (fashion "DOSE"). In your speech, if the frequency of the beeps increases significantly, this tells you if you are away from a potentially dangerous radioactive source (such radioactive sources are marked with yellow signs with the indication of dose rate). These values are returned to the database and compared with the values of personal dosimeter (if you have a dosimeter to year).
Model DMC2000: Quick User Guide (1 page fr/en) .pdf and complete datasheet (65 pages en) .pdf.
Where find an operationnal dosimeter (DMC) at CERN?
You must go to building 55 for a temporary or permanent registered DMC (depending on frequency of use) will be awarded.
Radioactive waste management
Why sort irradiated equipment, after all, it's going in the trash, right?
Cost of disposal of radioactive waste: 2 keuro / m3 if everything is sorted 80keuros / m3 if nothing is sorted. Hence the importance in sorting radioactive waste.
Material Handling
Then I put on gloves to protect myself?
Yes it's possible. Nevertheless, in the absence of RP instructions, these gloves do not improve radiation protection of persons.
Can I bring to my office a defective unit from the LHC?
No, if it comes from the tunnel (LHC tunnel = everything except UA, UL, US), because it must be controlled by RP before leaving the point. The case of materials from the UA is different and its classification will change with the operating time of the LHC, but the EPC is set to always store equipment LHC underground structures in the buffer zones for supply management issues. It was agreed that in the case of a picket action, individuals can store the same materials from the UA in areas buffers; However, this material must be controlled using the PICOMUR and resumed the next day by TE/EPC.
Equipment from underground facilities are they considered with no radiological risk? Can we desoldering components on the safe cards or special precautions?
From the tunnel (all except LHC UA, UL, US): On 1 January 2010, the RP set is that the equipment is considered radioactive, until RP, combining measures + knowledge of the state of the machine (losses, brightness, calculations ...) downgrades the equipment if it is safe. The decommissioned equipment can be processed normally and no special provision for any operation, destructive or not.
From UA, UL, US only: At 1 January 2010, the RP set is that the equipment is completely harmless and can be treated as standard equipment - not irradiated. Warning: individual cases of equipment that could be cooled (helium circuits, water passing through the tunnel).
How desoldering components of a map of a converter from underground LHC facilities and considered active?
Using a radiation - lab only. Contact the EPC team in charge of radiation protection subject to the procedure.
Is an RP control by measuring a buffer zone equipment (bunker) out of the tunnel may miss an activated component (for longer) within the module?
Not because although some materials can activate more easily than others (cross sections of higher interactions), other components must also be activated which would be visible with measuring instruments we use.
How should I process with a card, component or sub-assembly of equipment from the LHC underground facilities?
Any parts removed from an equipment (except if from UA, UL, US) must keep the particular classification of the equipment about the radiation risks. Specific signage is in place within the group. Contact the EPC team in charge of radiation protection subject to the procedure.
Radioactivity Measurement
What types of measurement equipment used by RP?
2 type mainly: a Geiger-Muller counter and a disintegration counting apparatus / second, giving the radioactive activity. (AD6 = Muller Geiger counter BGO scintillator = Bismuth Germanium (better sensitivity than scintillators NaI)).
General concepts
What types of ionizing radiation?
3 types exist: the alpha rays (emission of a helium nucleus 4 / 2He2), the gamma rays (emission of a photon), the beta rays (emission of a positron / electron and neutrino / antineutrino). Wikipedia article.
X-rays, what is it?
This is a radiation of the same nature as the type of radiation gamma but begotten differently. (Electronic transitions = X rays, radioactive decay of nuclei = gamma)
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