DSPEC 50
®
and DSPEC 502
®
Digital Gamma-Ray Spectrometer User’s Manual
932502G / 0618
corresponding hardware time stamp. Note that the second block will begin with another
C
ONNECTIONS
time stamp, which will correspond to another hardware time word. The data
acquisition program must associate the first C
ONNECTIONS
time stamp to the first hardware time
word and the second C
ONNECTIONS
time stamp to the second hardware time word even though
the first hardware time word appears after the second C
ONNECTIONS
time stamp. For example, if
you request 16384 words and the first returned word is 65532 indicating that 16380 data words
plus 4 overhead words were returned, you should immediately request another block of data.
The DSPEC 50 has buffer storage for up to 96k 32-bit words. Therefore, six requests may be
needed to drain the buffer and find all of the hardware time words. In practice, a program buffer
of 96k words would always hold enough data to drain an instrument buffer assuming that all six
requests were made in less than 1 second.
The following tables describe the format for the list-mode data as returned by C
ONNECTIONS
from the DSPEC 50:
The ADC Word contains a raw 14-bit ADC value and a 16-bit real time stamp. The Hardware
Time Word contains the same 16-bit real time stamp. In both cases this value represents the time
that the word was created as represented by an internal clock that increments every 200 ns. The
200 ns clock rolls over from 49999 to 0, which gives it a period of 10 ms. Every time the 200 ns
31 30
29 16
15 0
ADC Word
1 1
14-bit ADC value
16-bit real time in 200nS ticks
RT Word
1 0
30-bit real time in 10 ms ticks
LT Word
0 1
30-bit live time in 10 ms ticks
Table 3. Spectrometer List Mode Data Format.
31 24
23 16
15 8
7 0
Hdw Time
00000000
00000000
16-bit real time in 200nS ticks
C
ONNECTIONS
Time
00000001
Byte 2
Byte 1
Byte 0
C
ONNECTIONS
Time
00000010
Byte 5
Byte 4
Byte 3
C
ONNECTIONS
Time
00000011
00000000
Byte 7
Byte 6
ADC CRM
00000100
00000000
Counts per 10 ms period
Counter A (Sample Ready)
00000101
00000000
Counts per 10 ms period
Counter B (Gate)
00000110
00000000
Counts per 10 ms period
Table 4. Spectrometer List Mode Data Format.
136
Содержание DSPEC 50
Страница 4: ... Intentionally blank iv ...
Страница 8: ... Intentionally blank viii ...
Страница 10: ...x ...
Страница 26: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 16 ...
Страница 72: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 62 ...
Страница 76: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 66 ...
Страница 86: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 76 ...
Страница 132: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 122 ...
Страница 136: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 126 ...
Страница 144: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 134 ...
Страница 148: ...DSPEC 50 and DSPEC 502 Digital Gamma Ray Spectrometer User s Manual 932502G 0618 Intentionally blank 138 ...