1. Alpha counters for low background measurement
Moo Hyun Lee
1st alpha meeting

2. Alpha counters status (MooHyun Lee)
Alpha counter types and status
ZnS + Plastic Scintillator counter
Handheld alpha counter
Eljen EJ-440 (12”x12” sheet) 2 each delivered.
Silicon sensor (KNU)
A prototype was made and tested.
18.5% FWHM with Am-241 with an air gap
Ultralo-1800 (XIA)
Ionization chamber with Argon gas and no window.
Test material dimension: up to 1800 cm^2.
Can separate signals from the chamber.
~80 k USD including training
Ordered to have it shipping at the end of March 2015
Proportional wire chamber
S/N is big
Mylar window
Background from the chamber can not be separated
Well type Ge detector
CsI crystal detector (thin and wide)
Alpha meeting
Alpha counters status (MooHyun Lee)

3. Alpha counters status (MooHyun Lee)
EJ-440 (ZnS) delivered
12” x 12”
Alpha meeting
Alpha counters status (MooHyun Lee)

4. ZnS detector design and readout example
From an article in Progress in NUCLEAR SCIENCE and TECHNOLOGY,
Vol. 1, p (2011) (S.K.Lee et al.)
Alpha meeting
Alpha counters status (MooHyun Lee)

5. EJ-440 and BC-400 sandwich case
B.K. Seo et al., in Transactions of the Korean Nuclear Society Spring Meeting
Chuncheon, Korea, May
Alpha meeting
Alpha counters status (MooHyun Lee)

6. Alpha counters status (MooHyun Lee)
Backup slides
Alpha meeting
Alpha counters status (MooHyun Lee)

7. Alpha counters status (MooHyun Lee)
Silicon sensor (KNU)
A silicon PIN diode sensor has been developed and tested at KNU.
Excellent experiences with the solid state detectors compared to the gas detector in general.
Enough experiences in KNU.
From DongHa Kah’s slide
Alpha meeting
Alpha counters status (MooHyun Lee)

8. Alpha counters status (MooHyun Lee)
Silicon sensor test (KNU)
Alpha meeting
Alpha counters status (MooHyun Lee)

9. Alpha counters status (MooHyun Lee)
XIA UltraLo-1800 counter Alpha Particle Counter
Alpha meeting
Alpha counters status (MooHyun Lee)

10. Alpha counters status (MooHyun Lee)
UltraLo-1800 Specification
1 – Sample assumed to be 300mm wafer (count times drop by factor of 2.5 when using
max sample area)
Alpha meeting
Alpha counters status (MooHyun Lee)

11. Alpha counters status (MooHyun Lee)
UltraLo-1800 Schematic Overview
Alpha meeting
Alpha counters status (MooHyun Lee)

12. Alpha counters status (MooHyun Lee)
Proportional Counter Overview
Alpha meeting
Alpha counters status (MooHyun Lee)

13. Alpha counters status (MooHyun Lee)
UltraLo-1800 for different alphas locations
Alpha meeting
Alpha counters status (MooHyun Lee)

14. Alpha counters status (MooHyun Lee)
Alpha meeting
Alpha counters status (MooHyun Lee)

15. Alpha counters status (MooHyun Lee)
Alpha meeting
Alpha counters status (MooHyun Lee)

16. Alpha counters status (MooHyun Lee)
UltraLo-1800 requirements
Alpha meeting
Alpha counters status (MooHyun Lee)