Radiation Protection Instructions

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

2. 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 Frankfurt0.1 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

3. legal dose limits, implementation rules at DESY • Radiation Workers: Cat. A: 20 mSv/year Cat. B: 6 mSv/year • General Population: 1 mSv/year Since01-Aug-2001, the new German StrlSchV regulation “Strahlenschutzverordnung” requires the following dose limits for radiation workers and the general population:

4. personal dose measurement: Personal Dosimeters • PLD (Photo-LuminescenceDosimeter) 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:

5. 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!

6. statistics of personal doseat DESY

7. 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) Radiation Sources at DESY

8. 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

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

10. 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 2converter area, exception ruling permits fast passage where are the prohibited areas ?

11. Controlled Areas • In a controlled area at DESY, a personal dose > 1 mSv per yearcan be possible • Labeling: • Entry only with a Personal Dosimeter In case of potential neutron exposure, with additionalor integrated neutron dosimeter Exceptions are labeled in addition:

12. Controlled Areas at HERA HERMES experiment

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

14. 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

15. 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 !!!

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

17. Controlled Access (ZZ) Userarrives at closed interlock door: red lamp is on Usercontacts BKR via telephone and TV Operator notes down names, place and time

18. Controlled Access (ZZ) Usertakes key from the cabinet,exactly 1 key per person !!! Operator checks again that the accelerator is switched off and bridges the door contacts Useropens the door only after the red lamp (door tableau) is switched off

19. 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 !!!

20. working at accelerator components • radiation field has to be measuredwill be done by radiation protection group • wear personal dosimeterif necessary additional active dosimeter • be aware of contamination • wear working clothes • after finishing your work: • Change working clothes if necessary • Wash your hands

21. 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:

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

23. Radiation protection infoon the web • Additional important information can be found on the D3-Homepagewww.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 ...