JAEA-Review-2010-065.pdf:15.99MB - 日本原子力研究開発機構

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Detection of Photons Induced by a Single Ion Strike
S. Onoda, T. Makino and T. Ohshima
Environment and Industrial Materials Research Division, QuBS, JAEA
Single Event Effects (SEEs) are well known as a
malfunction of microelectronics devices caused by the
impact of the Galactic Cosmic Ray (GCR) such as high
energy heavy ions. Generally, SEEs are triggered by
unexpected transient currents induced by an ion incidence.
The focused ion microbeam has a key advantage in
evaluating the transient currents at specific region of a
device with a high resolution. Therefore we have
developed the system of transient current mapping by using
the heavy ion microbeams connected with both 3 MV
1)
tandem and AVF cyclotron accelerators . These are called
the Transient Ion Beam Induced Current (TIBIC) systems.
The powerful advantage of TIBIC mapping is the ability to
determine the position dependence of the event due to an ion
incidence. Although the microbeam has a lot of
advantages for SEE testing, the transporting and optimizing
microbeam require a lot of time and effort. Therefore the
mapping system with less effort is required. A different
way to perform mapping has been proposed by Sandia
2)
National Laboratory (SNL) . It is called the Ion Photon
Emission Microscopy (IPEM). To observe mapping using
IPEM, it is not necessary to focus the MeV ions at all.
Instead of microbeam, the position where ions strike the
sample is recorded together with the ion induced charge.
The position signals are detected by a Position Sensitive
Detector (PSD). In this study we used the high-sensitive
cooled Charge Coupled Device (CCD) Camera and the
Image Intensifier (I.I.) instead of PSD.
Figure 1 shows the photograph of measurement system
developed at TIARA facility. This system contains
following; (1) a beam extraction window (Kapton film)
under the mirror, (2) a sample (phosphor on Si diode) on
Cooled CCD Camera
Hamamatsu C4880
To oscilloscope
I. I.
Hamamatsu
C8600
XYZ
micro
stage
Objective
lens (5x)
Mirror
Diode
Oscilloscope
Amp.
Fig. 1 Photograph of measurement system.
JAEA-Review 2010-065
Kapton
Bias
supply
- 6 -
( a)
Diode
Phosphor
( b)
x20 x20
150MeV-Ar
Fig. 2 Micrograph of the phosphor on diode (a) and the
image of cooled CCD camera when the 150 MeV Ar
ions penetrate the phosphor on diode (b). White lines
indicate the contours of phosphor and diode.
micro XYZ stage, (3) an electronics for charge
measurements including amplifier, bias supply and
oscilloscope, and (4) a photon detection equipments
including the microscope (Olympus, BX51M), I.I.
(Hamamatsu, C8600), and Cooled CCD camera
(Hamamatsu, C4880-50-26A). The 150 MeV Ar beams
accelerated by the AVF Cyclotron are extracted from
vacuum to air via the Kapton film. The extracted Argon
(Ar) ion penetrates the phosphor on diode. The photons
from phosphor are detected by cooled CCD camera. At the
same time the ion induced charge in diode is recorded by the
oscilloscope.
Figure 2 shows the micrograph of phosphor on diode and
image of cooled CCD when 150 MeV Ar ions penetrate the
phosphor on diode. As shown the nine spots are detected
and each spot can be distinguished. Of course, applying
the beam attenuator the number of spots per one frame can
be controlled. The position where ion hit the sample can
be observed from the center of mass of each spot. The
diameter of spot is about 50 μm. Since the spot size
determines the resolution of map, it is necessary to find
another luminescence sheet. At the same time of CCD
image, the corresponding charge signal is measured by
oscilloscope. Combining the position and charge signal,
two dimensional map of charge collection on diodes can be
observed.
References
1) T. Hirao et al., Nucl. Instrum. Meth. B 267 (2009) 2216.
2) B. L. Doyle et al., Nucl. Instrum. Meth. B 181 (2001)
199.
Acknowledgement
The part of this study was supported by the Grant-in-Aid
for Young Scientists (B) No. 20760051 from the Ministry of
Education, Culture, Sports, Science and Technology of Japan.