Section 5. High Speed Photometer

Calibrations that may be applied to High Speed Photometer (HSP) files include (1) nonlinearity correction due to dead time in digital data, (2) dark signal subtraction, (3) current-to-voltage converter (CVC) offset subtraction for analog data, (4) pre-amplifier signal subtraction, (5) division of high voltage factor due to the detector’s different efficiency at different high voltage setting, (6) division of gain factor due to the detector’s different current gain at different gain setting for analog data, and (7) division of detector efficiency due to possibly slight difference in different apertures sharing the same filter. The reference tables described in this document are used to supply these calibration quantities.

In addition, when an extended target is observed, the count rate per unit area may be preferred, and thus an aperture area reference table is needed. Also, each detector has designated spots used to calibrate the dark signals. A cross-reference table between these dark apertures and regular apertures is also used to carry out the calibration of HSP.

5.1 HSP Reference Relations and STSDAS Tables

5.1.1 Aperture Areas Table: <unique name>.CV0

The aperture areas table contains the names and areas of all the HSP’s apertures and is used by the HSP calibration. The aperture names are the same as those used to retrieve data from the .CV4 and .CV9 tables; thus every aperture retrieved from the . CV0 table must have an entry in the . CV4 table and one in the .CV9 table. The .CV0 table is loaded only from the project data base tape.

Format: Each entry contains an aperture name and an aperture area, which is used to convert HSP count rates into count rates per square arc-second. Additionally, there is a POINTER field that is a dummy field and is not used to hold data.

Table 5-1 shows the structure of the aperture areas table.

Table 5-1. HSP Aperture Areas Table, <unique name>. CV0

Column Name

Data Type

Units

Description

APER_NAME

CH*10

Name of aperture (SOGS aperture naming convention)

POINTER

I

Not used

APER_SIZE

D

arcsec2

Aperture area

5.1.2 High Voltage Factor Table: < unique name>.CV1

The high voltage factor table contains the coefficients and base values used in computing the high voltage detector characteristic (H) for the HSP calibration.

Format: Each set of base values and coefficients corresponds to a particular HSP detector high voltage setting (command value) and data type. In each set there are a base value, a reference time, a reference temperature, and 16 polynomial coefficients. Additionally, there is a POINTER field that is a dummy field and is not used to hold data.

Selection Scheme: Records are selected on the basis of detector number, type (ANALOG or DIGITAL), and high voltage setting.

Restrictions: In the high voltage factor table, there should be entries for the three standard voltage settings (corresponding to photoelectric current gains of 0.5E+6, 1.0E+6, and 2.0E+6) for each detector and data type (ANALOG/DIGITAL).

The STSDAS table produced is called <unique name>.CV0; Table 5-2 shows its structure.

Table 5-2. HSP High Voltage Factor Table, <unique name>. CV1

Column Name

Data Type

Units

Description

DET_NUM

I

digital number

Detector number, 1-5

TYPE

CH*7

none

ANALOG, DIGITAL

VOLTAGE

I

digital number

High voltage setting (command value)

POINTER

I

Not used

BASE_VALUE

R

none

Base value of the characteristic scaling polynomial

BASE_TEMP

R

deg Celsius

Base temperature of the characteristic scaling polynomial

BASE_TIME

D

MJD

Base time of the characteristic scaling polynomia l(Modified Julian Date)

A00

D

none

0,0th coefficient of the characteristic scaling polynomial

A01

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A02

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A03

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A10

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A11

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A12

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A20

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A21

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A22

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A30

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

A31

D

deg-3 day-1

3,1st coefficient of the characteristic scaling polynomial

A32

D

deg-3 day-2

3,2nd coefficient of the characteristic scaling polynomial

A33

D

deg-3 day-3

3,3rd coefficient of the characteristic scaling polynomial

5.1.3 Gain Factor Table: <unique name>.CV2

The gain factor table contains the coefficients and base values used to compute the gain detector characteristic (G) for the HSP calibration.

Format: Each set of base values and coefficients corresponds to a particular HSP detector and a gain setting (command value). In each set there are a base value, a reference time, a reference temperature, and 16 polynomial coefficients.

Selection Scheme: Records are selected on the basis of detector number and gain setting.

Restrictions: In the gain factor table, for each detector there should be entries for each of the five gain settings (0, 2, 3, 6, and 7).

Table 5-3 shows the structure of the HSP gain factor table.

Table 5-3. HSP Gain Factor Table, <unique name>. CV2

Column Name

Data Type

Units

Description

DET_NUM

I

digital number

Detector number, 1-5

VGAIND

I

digital number

Gain setting: 0, 2, 3, 6, 7

BASE_VALUE

R

DN/(counts/sec)

Base value of the characteristic scaling polynomial

BASE_TEMP

R

deg Celsius

Base temperature of the characteristic scaling polynomial

BASE_TIME

D

MJD

Base time of the characteristic scaling polynomial

A00

D

none

0,0th coefficient of the characteristic scaling polynomial

A01

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A02

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A03

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A10

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A11

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A12

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A20

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A21

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A22

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A30

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

A31

D

deg-3 day-1

3,1st coefficient of the characteristic scaling polynomial

A32

D

deg-3 day-2

3,2nd coefficient of the characteristic scaling polynomial

A33

D

deg-3 day-3

3,3rd coefficient of the characteristic scaling polynomial

5.1.4 Pre-amp Table: <unique name>.CV3

The pre-amp table contains the coefficients and base values used in computing the pre-amplifier detector characteristic (E) for the HSP calibration. The PRE AMP detector characteristic (E) is the contribution to the digital count rate or analog current from the electronics.

Format: Each set of base values and coefficients corresponds to a particular HSP detector and data type. In each set there are a base value, a reference time, a reference temperature, and 16 polynomial coefficients.

Selection Scheme: Records are selected on the basis of detector number and data type

(ANALOG or DIGITAL).

Restrictions: In the pre-amp table, there should be an entry for each detector and data type

(ANALOG/DIGITAL). Table 5-4 shows the structure of the HSP pre-amp table.

Table 5-4. HSP Pre-amp Table, <unique name>. CV3

Column Name

Data Type

Units

Description

DET_NUM

I

digital number

Detector number, 1-5

TYPE

CH*7

none

ANALOG, DIGITAL

BASE_VALUE

R

none

Base value of the characteristic scaling polynomial

BASE_TEMP

R

deg Celsius

Base temperature of the characteristic scaling polynomial

BASE_TIME

D

MJD

Base time of the characteristic scaling polynomial

A00

D

none

0,0th coefficient of the characteristic scaling polynomial

A01

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A02

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A03

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A10

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A11

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A12

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A20

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A21

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A22

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A30

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

A31

D

deg-3 day-1

3,1st coefficient of the characteristic scaling polynomial

A32

D

deg-3 day-2

3,2nd coefficient of the characteristic scaling polynomial

A33

D

deg-3 day-3

3,3rd coefficient of the characteristic scaling polynomial

5.1.5 Efficiency Table: <unique name>.CV4

The efficiency table contains the coefficients and base values used in computing the efficiency (relative sensitivity) detector characteristic (R) for the HSP calibration.

Format: Each set of base values and coefficients corresponds to a particular HSP aperture and detector. In each set there are point and extended base values, a reference time, a reference temperature, and 16 polynomial coefficients.

**Selection Scheme: Records are selected on the basis of detector number and aperture name. Table 5-5 shows the structure of STSDAS table <unique name>.CV4.

Table 5-5. HSP Efficiency Table, <unique name>. CV4

Column Name

Data Type

Units

Description

APER_NAME

CH*10

None

Aperture name identifier

DET_NUM

I

digital number

Detector number, 1-5

VGAIND

I

digital number

Gain setting: 0, 2, 3, 6, 7

BASE_VALUE_P

R

none

Point source base value of the characteristic scaling polynomial

BASE_VALUE_E

R

none

Extended source base value of the characteristic scaling polynomial

BASE_TEMP

R

deg Celsius

Base temperature of the characteristic scaling polynomial

BASE_TIME

D

MJD

Base time of the characteristic scaling polynomial

A00

D

none

0,0th coefficient of the characteristic scaling polynomial

A01

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A02

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A03

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A10

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A11

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A12

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A20

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A21

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A22

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A30

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

A31

D

deg-3 day-1

3,1st coefficient of the characteristic scaling polynomial

A32

D

deg-3 day-2

3,2nd coefficient of the characteristic scaling polynomial

A33

D

deg-3 day-3

3,3rd coefficient of the characteristic scaling polynomial

5.1.6 Dark Count Table: <unique name>.CV5

The dark count table contains the coefficients and base values used in computing the dark count characteristic (D) for the HSP calibration.

Format: Each set of base values and coefficients corresponds to a particular HSP dark aperture, a high voltage setting (command value), and data type. In each set there are a base value, a reference time, a reference temperature, and 16 polynomial coefficients. Additionally, there is a POINTER field that is a dummy field and is not used to hold data.

Selection Scheme: Records are selected on the basis of dark aperture name, data type (ANALOG or DIGITAL), and high voltage setting (command value).

Restrictions: In the dark count table, there should be entries for the three standard voltage settings (corresponding to photoelectric current gains of 0.5E+6, 1.0E+6, and 2.0E+6) for each dark aperture and data type (ANALOG/DIGITAL).

Table 5-6 shows the structure of the STSDAS table <unique name>.CV5.

Table 5-6. HSP Dark Count Table, <unique name>. CV5

Column Name

Data Type

Units

Description

APER_NAME

A33

D

deg-3 day-1

TYPE

CH*10

D

deg-3 day-2

VOLTAGE

CH*7

None

deg-3 day-3

POINTER

I

NONE

Dark aperture name identifier

BASE_VALUE

I

digital number

ANALOG, DIGITAL

BASE_TEMP

R

High voltage setting (command value) Not used

BASE_TIME

R

Counts/sec

Base value of the characteristic scaling polynomial

A00

D

deg Celsius

Base temperature of the characteristic scaling polynomial

A01

D

MJD

Base time of the characteristic scaling polynomial

A02

D

none

0,0th coefficient of the characteristic scaling polynomial

A03

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A10

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A11

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A12

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A20

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A21

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A22

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A30

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A31

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A32

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

5.1.7 Time Bias Table: < unique name>.CV6

The time bias table contains the time biases that are used to correct the integration time for internal instrument delays.

Format: Each entry contains a time bias for a particular HSP data format (BYTE, WORD, LWRD, ALOG, or ALL) and for a particular instrument mode (SCP, ARS, SSP1, or SSP2).

Selection Scheme: Records are selected on the basis of data format and instrument mode. Restrictions: For each instrument mode there should be entries for each of the five data formats. Table 5-7 shows the structure of the HSP time bias table.

Table 5-7. HSP Time Bias Table, <unique name>. CV6

Column Name

Data Type

Units

Description

DATA_FMT

CH*4

none

Data format

MODE

CH*4

none

Instrument mode

TIME_BIAS

I

clock count

Internal instrument delay added to integration times

5.1.8 CVC Offset Table: <unique name>.CV7

The CVC offset table contains the coefficients used in computing the current-to-voltage converter (CVC) offset detector characteristic (I) for the HSP calibration.

Format: Each set of base values and coefficients corresponds to a particular HSP detector and analog gain setting (command value). In each set there are a base value, a reference time, a reference temperature, and 16 polynomial coefficients.

Selection Scheme: Records are selected on the basis of detector number and gain setting.

Restrictions: In the CVC offset table, for each detector there should be entries for each of the five gain settings (0, 2, 3, 6, and 7).

Table 5-8 shows the structure of the HSP CVC offset table.

Table 5-8. HSP CVC Offset Table, <unique name>. CV7

Column Name

Data Type

Units

Description

DET_NUM

I

digital number

Detector number, 1-5

VGAIND

I

digital number

Gain setting: 0, 2, 3, 6, 7

BASE_VALUE

R

digital number

Base value of the characteristic scaling polynomial

BASE_TEMP

R

deg Celsius

Base temperature of the characteristic scaling polynomial

BASE_TIME

D

MJD

Base time of the characteristic scaling polynomial

A00

D

none

0,0th coefficient of the characteristic scaling polynomial

A01

D

day-1

0,1st coefficient of the characteristic scaling polynomial

A02

D

day-2

0,2nd coefficient of the characteristic scaling polynomial

A03

D

day-3

0,3rd coefficient of the characteristic scaling polynomial

A10

D

deg-1

1,0th coefficient of the characteristic scaling polynomial

A11

D

deg-1 day-1

1,1st coefficient of the characteristic scaling polynomial

A12

D

deg-1 day-2

1,2nd coefficient of the characteristic scaling polynomial

A13

D

deg-1 day-3

1,3rd coefficient of the characteristic scaling polynomial

A20

D

deg-2

2,0th coefficient of the characteristic scaling polynomial

A21

D

deg-2 day-1

2,1st coefficient of the characteristic scaling polynomial

A22

D

deg-2 day-2

2,2nd coefficient of the characteristic scaling polynomial

A23

D

deg-2 day-3

2,3rd coefficient of the characteristic scaling polynomial

A30

D

deg-3

3,0th coefficient of the characteristic scaling polynomial

A31

D

deg-3 day-1

3,1st coefficient of the characteristic scaling polynomial

A32

D

deg-3 day-2

3,2nd coefficient of the characteristic scaling polynomial

A33

D

deg-3 day-3

3,3rd coefficient of the characteristic scaling polynomial

5.1.9 Dead Time Table: < unique name>.CV8

The dead time table contains the coefficients and base values in computing the dead time (tau), which is used for paired-pulse corrections in HSP calibration.

Format: Each set of base values and coefficients corresponding to a particular HSP detector, high voltage setting (command value), and pulse amplifier/discriminator (PAD) threshold setting (command value). In each set there are a base value, a reference temperature, and one

coefficient.

Selection Scheme: Records are selected on the basis of detector number, high voltage setting, and PAD threshold setting.

Restrictions: In the dead time table, there should be entries for the three standard high voltage settings (corresponding to photoelectric current gains of 0.5E+6, 1.0E+6, 2.0E+6) for each detector and PAD threshold setting(s) (usually one).

Table 5-9 shows the structure of the HSP dead time table.

Table 5-9. HSP Dead Time Table, <unique name>. CV8

Column Name

Data Type

Units

Description

DET_NUM

I

digital number

Detector number, 1-5

VOLTAGE

I

digital number

High voltage setting (command value)

THRESH

I

digital number

PAD threshold setting (command value)

BASE_VALUE

R

sec

Base value of dead time

A1

R

sec/deg

Dead time temperature dependence coefficient

BASE_TEMP

R

deg

Celsius Temperature zero point used in temperature dependence

5.1.10 Dark Aperture Table: <unique name>.CV9

The dark aperture table contains the corresponding dark aperture names for each of the regular HSP aperture names. The dark aperture names are later used to calibrate HSP dark counts.

Format: Each regular HSP aperture name has a corresponding dark aperture name. Each image dissector tube (IDT) has three dark apertures, and the photo-multiplier (PMT) has one dark aperture name.

Selection Scheme: Records are selected on the basis of aperture name and detector number.

Restrictions: The dark aperture table may contain aperture names that refer to the same aperture as another name. In this case, the redundant names are eliminated by setting both to the same name.

Table 5-10 shows the structure of the dark aperture table.

Table 5-10. HSP Dark Aperture Translation Table, <unique name>. CV9

Column Name

Data Type

Units

Description

APER_NAME

CH*10

none

Regular aperture name

DET_NUM

I

digital number

Detector number

DARK_APER

CH*10

none

Dark aperture name