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Radiation Protection Instructions

Introduction: Radiation and Dose

Radiation Protection Areas

DESY internal Rules and Regulations

K. Peter Schüler HERMES

25 – Jan - 2005

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natural radiation level in Germany 1-2 mSv / year

roundtrip flight btw. New York Frankfurt 0.1 mSv

CAT scan of lungs or abdomen 5 – 30 mSv

legal limit for non-radiation workers 1 mSv / year legal limit for persons of category B 6 mSv /

year lethal dose (for single whole body exposure) 4-5

Sv

Definition of dose, examples Absorbed Dose = absorbed energy per mass

(unit: 1 Gy = 1 joule / kg = 100 rad) Equivalent Dose (for biological damage) =

absorbed dose x wR (biological factor)

wR = 1 (, e, ), wR = 5 – 20 (p, n, )

unit: 1 Sv (Sievert) = 1 joule / kg = 100 rem

Examples:

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legal dose limits, implementation rules at DESY

Radiation Workers: Cat. A: 20 mSv / year

Cat. B: 6 mSv / year

General Population: 1 mSv / year

Since 01-Aug-2001, the new German StrlSchV regulation “Strahlenschutzverordnung” requires the following dose limits for radiation workers and the general population:

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personal dose measurement:

Neutron-Film-Dosimeter

(nuclear emulsion type)

for neutron dose (> 0.1 mSv)

Personal Dosimeters PLD (Photo-Luminescence Dosimeter)

for photon / electron dose (> 0.1 mSv)

both dosimeter types are integrated into a single unit:

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your personal dosimeter:East Hall – 7th Floor:

when you arrive: pick it up from the panels when you leave: always return it to the panels!

A - L M - Z

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statistics of personal doseat DESY

2002 2003 2004 (Aug)

Phot. Neut. Phot. Neut. Phot. Neut.

no. of pers. dos‘s 1317 317 1474 585 1500 1500

annual dose range

< 0.1 mSv 1290 315 1399 570 1481 1451

0.1 – 1.0 mSv 27 2 75 15 19 49

1 – 6 mSv 0 0 0 0 0 0

6 – 20 mSv 0 0 0 0 0 0

> 20 mSv 0 0 0 0 0 0

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Radiation Sources at DESY

acceleratorsacceleratorssynchrotron radiation (X-rays)primary beam losses (e-, p-showers)secondary radiation (, neutrons)

background sourcesbackground sources

Klystrons & Cavities (X-rays)

radioactive materialsradioactive materials radioactive sources () activated materials ()

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Labeling of radiation fields

Radiation protection areas: prohibited area - „Sperrbereich” controlled area - „Kontrollbereich“

Labeling of radioactive materials:

VORSICHT RADIOAKTIVITÄT

measurements and labeling will be done by the radiation protection group D3

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Prohibited Areas A prohibited area is an area with a possible

local dose > 3 mSv per hour Labeling:

Frei an PETRA - Wartungstagen

Exceptions are labeled in addition:

!!! Entry to a prohibited area is strictly forbidden !!!

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where are the prohibited areas ?

all accelerator roomsall accelerator rooms, , when the accelerator is when the accelerator is

on, protected by an on, protected by an interlock system interlock system

Some adjacent areas, Some adjacent areas, when the accelerator is when the accelerator is on, such as tunnel on, such as tunnel ceilings at PETRA, HERA, ceilings at PETRA, HERA, Linac 3, TTF 2Linac 3, TTF 2

areas with high rf-power,areas with high rf-power, protected by anprotected by an

interlock systeminterlock system

Linac 2Linac 2 converter area,converter area, exception ruling permitsexception ruling permits

fast passagefast passage

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Controlled Areas In a controlled area at DESY, a personal dose

> 1 mSv per year can be possible Labeling:

Entry only with a Personal Dosimeter

In case of potential neutron exposure, with

additional or integrated neutron dosimeter

Exceptions are labeled in addition:

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Controlled Areas at HERA

accelerator statusaccelerator statusonon offoff

HERA-NHERA-Nas of 1.12.2003as of 1.12.2003

room 100 room 100

(exp. hall), (exp. hall),

aux. staircase aux. staircase 6th floor 6th floor

nonenone

HERA-S HERA-S as of 15.12.2003as of 15.12.2003

room 100 room 100

(exp. hall)(exp. hall)

Uranium calorimeterUranium calorimeter

HERA-WHERA-Was of 15.12.2003as of 15.12.2003

completely completely

(from access doors) (from access doors)

exception: BSG roomsexception: BSG rooms

tunnel WL: tunnel WL:

FS-door to p-inj. (200m)FS-door to p-inj. (200m)

HERA-OHERA-Oas of 15.12.2003as of 15.12.2003

room 100 room 100

(exp. hall)(exp. hall)

nonenone

HERMES experiment

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DESY rules in controlled areas

Entry is only allowed if: there is a working

mission the personal dose will

be measured a radiation protection

instruction was given

Entry is not allowed for: minors <18 years pregnant & nursing

women visitors

In controlled areas it is forbidden: to eat, drink and smoke

but, eating & drinking permitted in the HERMES „control room“ (101) and smoking in the designated area adjacent to the hall, as in the past !!!

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Switching on an accelerator

Warning message:

„Tunnel search !Please leave the tunnel !“

1. Search of the accelerator tunnel

Information for people performing the search:

• High responsibility

• Knowledge of place

• No time pressure

• Sufficient number of people

• Use resources (e.g. pocket lamp)

• Protocol of action

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2. Warning signals before the accelerator is going to be switched on

Yellow warning lamps will be switched on

Lights will be dimmed Warning message for 1 minute

Example: „Attention: HERA is going to be switched on !“

The searched area is now a prohibited area

after all these warnings the accelerator can be switched on at any time !!!

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3. Emergency actions to be taken(if you hear or see warning signals

and you or somebody elsehave not yet left the interlocked area)

Escape through one of the interlock doors

Push an

emergency button

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Controlled Access (ZZ)

User arrives at closed interlock door:

red lamp is on

User contacts BKR via telephone and TV

Operator notes down names, place and time

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Controlled Access (ZZ)

User takes key from the cabinet, exactly 1 key per person !!!

Operator checks again that the accelerator is switched off and bridges the door contacts

User opens the door only after the red lamp (door tableau) is switched off

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radioactive materials

potential activation of

accelerator components(vacuum pipe, collimators,

magnets, ...)

So, be aware that some components near the

accelerator beam lines may be

radioactive !!!

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working at accelerator components

radiation field has to be measured will be done by radiation protection group

wear personal dosimeter if necessary additional active dosimeter

be aware of contamination wear working clothes after finishing your work:

Change working clothes if necessary Wash your hands

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Before you remove any components from an accelerator

VORSICHT RADIOAKTIVITÄT

measurement of radioactivity by D3

Linac2, PIA, DESY 2/3, TTF: all components

Storage rings: only beam pipes, cavities andcomponents which are located near or at the beam lines

if components are radioactive you will find the labeling:

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What to do with radioactive components?

Transport on DESY site and to HERA halls: only by instructed people

Storage outside of accelerator: theft protection and labeling needed

Mechanical processing: only with agreement of D3

Shipment: only with agreement of D3

Waste disposal: only by D3

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Radiation protection info on the web

Additional important information can be found on the D3-Homepage www.desy.de/d3/d3index.html

Laws and regulations DESY internal regulations Radiation protection organization Responsibilities inside D3 Radiation protection instructions Important dates and a lot more ...