XIS Spaced-row Charge Injection (SCI)
Dec 20, 2006 the XIS team
What is the spaced-row charge injection?
The XIS has suffered the radiation damage, and the energy resolution has
got worse. To recover the degradation, we decide to employ a spaced-row
charge injection as shown in the right figure. Though this reduces the
effective area, the energy resolution becomes much improved.
The radiation damage makes gtrapsh in X-ray CCD pixels.
These traps obstruct the event transfer, which causes the degradation.
However, if we put charges in front of X-ray events,
these charges work as gsacrificalh events; they fill the traps and
the X-ray events are transferred smoothly.
Then we can restore the eneregy resolution.
Results of test observation
We can see how the SCI works in the figure.
The energy resolution is successfully improved from 200 eV to 150 eV.
The center pulse height of Fe Kalpha line becomes large when we use the SCI.
This means X-ray events are transferred with little charge loss.
ISAS/JAXA Department of High Energy Astrophysics
Last Modified: Tuesday, 09-Jan-2007 13:37:02 JST