Radiation Protection Instructions K. Peter Schüler HERMES 25 – Jan - 2005 Radiation Protection Instructions Introduction: Radiation and Dose Radiation Protection Areas DESY internal Rules and Regulations

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: 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

legal dose limits, implementation rules at DESY Since 01-Aug-2001, the new German StrlSchV regulation “Strahlenschutzverordnung” requires the following dose limits for radiation workers and the general population: Radiation Workers: Cat. A: 20 mSv / year Cat. B: 6 mSv / year General Population: 1 mSv / year

personal dose measurement: Personal Dosimeters PLD (Photo-Luminescence Dosimeter) for photon / electron dose (> 0.1 mSv) Neutron-Film-Dosimeter (nuclear emulsion type) for neutron dose (> 0.1 mSv) both dosimeter types are integrated into a single unit:

your personal dosimeter: East Hall – 7th Floor: A - L M - Z when you arrive: pick it up from the panels when you leave: always return it to the panels!

statistics of personal dose at DESY 2002 2003 2004 (Aug) Phot. Neut. no. of pers. dos‘s 1317 317 1474 585 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 6 – 20 mSv > 20 mSv

Radiation Sources at DESY accelerators synchrotron radiation (X-rays) primary beam losses (e-, p-showers) secondary radiation (g, neutrons) background sources Klystrons & Cavities (X-rays) radioactive materials radioactive sources (a, b, g) activated materials (a, b, g)

Labeling of radiation fields Radiation protection areas: prohibited area - „Sperrbereich” controlled area - „Kontrollbereich“ Labeling of radioactive materials: measurements and labeling will be done by the radiation protection group D3

!!! Entry to a prohibited area is Exceptions are labeled in addition: Prohibited Areas A prohibited area is an area with a possible local dose > 3 mSv per hour Labeling: !!! Entry to a prohibited area is strictly forbidden !!! Exceptions are labeled in addition:

where are the prohibited areas ? all accelerator rooms, when the accelerator is on, protected by an interlock system Some adjacent areas, when the accelerator is on, such as tunnel ceilings at PETRA, HERA, Linac 3, TTF 2 areas with high rf-power, protected by an interlock system Linac 2 converter area, exception ruling permits fast passage

Exceptions are labeled in addition: 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:

Controlled Areas at HERA accelerator status on off HERA-N as of 1.12.2003 room 100 (exp. hall), aux. staircase  6th floor none HERA-S as of 15.12.2003 (exp. hall) Uranium calorimeter HERA-W as of 15.12.2003 completely (from access doors) exception: BSG rooms tunnel WL: FS-door to p-inj. (200m) HERA-O HERMES experiment

DESY rules in controlled areas Entry is not allowed for: minors <18 years pregnant & nursing women visitors In controlled areas it is forbidden:  to eat, drink and smoke Entry is only allowed if: there is a working mission the personal dose will be measured a radiation protection instruction was given but, eating & drinking permitted in the HERMES „control room“ (101) and smoking in the designated area adjacent to the hall, as in the past !!!

Switching on an accelerator 1. Search of the accelerator tunnel Warning message: „Tunnel search ! Please leave the 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

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 !!!

3. Emergency actions to be taken (if you hear or see warning signals and you or somebody else have not yet left the interlocked area) Escape through one of the interlock doors Push an emergency button

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

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

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 !!!

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

Before you remove any components from an accelerator measurement of radioactivity by D3 Linac2, PIA, DESY 2/3, TTF: all components Storage rings: only beam pipes, cavities and components which are located near or at the beam lines if components are radioactive you will find the labeling:

What to do with radioactive components? Mechanical processing: only with agreement of D3 Storage outside of accelerator: theft protection and labeling needed Shipment: only with agreement of D3 Waste disposal: only by D3 Transport on DESY site and to HERA halls: only by instructed people

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 ...