1. Radiation Protection Instructions
K. Peter Schüler HERMES
25 – Jan
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 = 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 = rem
Examples:
natural radiation level in Germany mSv / year
roundtrip flight btw. New York  Frankfurt mSv
CAT scan of lungs or abdomen – 30 mSv
legal limit for non-radiation workers mSv / year
legal limit for persons of category B mSv / year
lethal dose (for single whole body exposure) Sv

3. 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: mSv / year
General Population:
1 mSv / year

4. 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:

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 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

7. 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)

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. !!! 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:

10. 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

11. 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:

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

13. 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 !!!

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 signals and you or somebody else have not yet left the interlocked area)
Escape through one of the interlock doors
Push an
emergency button

17. 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

18. 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

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 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

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
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

23. Radiation protection info on the web
Additional important information can be found on the D3-Homepage
Laws and regulations
DESY internal regulations
Radiation protection organization
Responsibilities inside D3
Radiation protection instructions
Important dates
and a lot more ...