1. T-489: Induced Activity and Residual Dose Rates
Irradiation Experiment in Endstation A Spring 2007
Johannes Bauer
for T-489 experimenters
prepared 3/19/2007

2. Motivation Monte Carlo Simulations for Design of New Facilities
Simulation of residual activity improved in last years
Better-controlled experiments needed for benchmark tests
CERN Involvement:
Four collaborators from CERN
Two years ago similar experiment at CERN with hadron beam
SLAC experiment complimentary with electron beam
3/19/2007

3. Experimental Setup Beam
Primary beam 28.5 GeV at 20 W average (up to 100 W temporarily), ~ 2x109 e-/pulse at 1 to 10 Hz (not exceeding 100 W)
Compatible with PEP2 and BABAR
Beams delivered to dedicated copper dump
Need to know absolute beam power to ~5%
Equipment
Use of existing wire scanner 3WS1 and standard roller screens for beam monitoring and alignment
Use of existing toroids to measure current
Infrastructure
Just standard beam delivery
3/19/2007

4. Samples at Dump
Installation in beam line inside shielding tunnel of ESA
Regularly controlled
access to remove
and replace samples
Measurements of samples in Bldg.24
3/19/2007

5. Schedule Installation
Official schedule: Mon/Tue April 2/3, (earlier if access to ESA possible)
Beam
Starting Wed April 4, 2007 for 5 to 7 days (earlier if beams available)
3/19/2007

6. Values for 100 hours cooling time
Radiation Hazards
Concrete in ESA
Already irradiated T-489 does not add much: < 0.01 mrem/h
Equipment in ESA
Also very little: ~ 0.13 mrem/h
Dump
1 mrem/h at 30 cm distance off dump surface
13 mrem/h on contact
Values for 100 hours cooling time
3/19/2007

7. Radiation Hazards (cont)
Worst case radiation dose
according to simulation, 4 days, 20 W, 15 min cooling time:
contact
30 cm
Dump
2000 mrem/h
130 mrem/h
sample
(worst case stainless steel )
2 mrem/h
0.02 mrem/h
Dump’s 30 cm dose rate:
70 mrem/h after 30 min cooling time
50 mrem/h after 1 hour cooling time
20 mrem/h after 10 hours cooling time
3/19/2007

8. Radiation Hazards (cont)
Exposure during sample exchange (4 days of 20 W, 15 min cool-down):
Task
Dose rate
Time
Dose
Approaching dump
1 mrem/h
1 minute
0.017 mrem
Exchanging sample
130 mrem/h
20 seconds
0.72 mrem
Leaving dump
1 minutes
Total
0.76 mrem
Training and rehearsals will be required
Radiological postings and procedures worked out with RPFO
3/19/2007

9. Conclusion
Radiological aspects under control both short-term and long-term
No additional safety hazards (e.g. no earthquake bracing needed for equipment)
3/19/2007