F OS DEAD AND NOISY DIODES UPD A TE JENNIFER A CHRISTENSEN - PDF document

F OS DEAD AND NOISY DIODES UPD A TE JENNIFER A� CHRISTENSEN and STEPHAN E� MAR TIN Sp ac e T elesc op e Scienc e Institute ���� San Martin Drive Baltimor e MD ����� Abstract� This pap er lists all the kno wn dead� noisy � and susp ect dio des for b oth the F OS�RED and F OS�BLUE detectors as of the end of April ����� Key w ords� F OS� HST Instrumen ts� Dead dio des �� In tro duction In this pap er w e presen t a summary of all the kno wn and susp ected dead and noisy dio des on b oth fo the F OS detectors� When one of the ��� dio des on either side is noticed to b ecome noisy or ceases to collect data� the F OS team initiates a monitor on the susp ected dio de� If there are � separate o ccurances of un usual b eha vior� the dio de will b e �agged as dead or noisy � and will b e turned o�� As the F OS team do es not regularly monitor all the data coming do wn from the telescop e� w e rely on observ ers to w arn us of p ossible dead or noisy dio des� as w ell as sp ot�c hec ks of our o wn� A dead or noisy dio de w ould app ear in a sp ectrum as an absorbtion or emission feature that is exactly �O VERSCAN �NXSTEPS� pixels wide� �In our usual mo de for obtaining sp ectra� this w ould b e �� pixels in width�� A further discussion on ho w to iden tify p ossible problem dio des can b e found in the HST Data Handb o ok � pp ��������

CHRISTENSEN � MAR TIN T ABLE I F OS�BLUE susp ect and dead dio des Disabled Disabled Disabled Enabled Date Dead Noisy Cross�wired p ossibly Rep orted Dio de Dio de Dio de bad �� �� �� � Sept ���� ��� �� �� ��� Jan ���� ��� ��� ��� ��� ��� ������� Aug ���� ��� ��� ��� Aug ���� ��� ��� ��� ��� ��� ��� No v ���� ��� ��� ��� ��� ��� ��� ��� ��� ��� ��� � �� � � Calibr ating HST� Post Servicing Mission

F OS DEAD DIODES T ABLE I I F OS�RED susp ect and dead dio des Disabled Disabled Enabled Date Dead Noisy p ossibly Rep orted Dio de Dio de bad � ��� �� July ���� � ��� ������� July ���� ��x� �� ��� ��� July ���� ��� ��� ��� Ma y ���� ��� ��� ��� Dec ���� ��� ��� ��� Sept ���� ��� ��� ��� F eb ���� ��� ������� Oct ���� ��� July ���� ��� Mar ���� ��� Mar ���� ��x� ��� Apr ���� � � �� Calibr ating HST� Post Servicing Mission