Threshold conversions
From RHESSI Wiki
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== Front slow threshold == | == Front slow threshold == | ||
- | Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x0C. | + | Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x0C, which is ~3 keV. |
{| class="wikitable" | {| class="wikitable" | ||
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! scope="row" | 0x80 | ! scope="row" | 0x80 | ||
| 25.9 || 25.3 || 24.0 || 25.1 || 25.6 || 24.3 || 24.5 || 25.6 || 23.8 | | 25.9 || 25.3 || 24.0 || 25.1 || 25.6 || 24.3 || 24.5 || 25.6 || 23.8 | ||
+ | |- | ||
+ | ! scope="row" | 0xC0 | ||
+ | | 38.6 || 37.7 || 35.7 || 37.4 || 38.2 || 36.3 || 36.8 || 38.2 || 35.5 | ||
|- | |- | ||
! scope="row" | 0xFF | ! scope="row" | 0xFF | ||
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== Front fast threshold == | == Front fast threshold == | ||
- | The nominal DAC setting is 0x22. | + | The nominal DAC setting is 0x22, which is ~6 keV. |
== Rear slow threshold == | == Rear slow threshold == | ||
- | Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x30. | + | Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x30, which is ~20 keV. |
{| class="wikitable" | {| class="wikitable" | ||
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! scope="row" | 0x80 | ! scope="row" | 0x80 | ||
| 40.0 || 38.5 || 40.1 || 40.5 || 39.7 || 39.8 || 39.9 || 36.6 || 36.0 | | 40.0 || 38.5 || 40.1 || 40.5 || 39.7 || 39.8 || 39.9 || 36.6 || 36.0 | ||
+ | |- | ||
+ | ! scope="row" | 0xC0 | ||
+ | | 52.6 || 50.7 || 52.9 || 53.5 || 51.9 || 52.4 || 55.3 || 50.6 || 47.9 | ||
|- | |- | ||
! scope="row" | 0xFF | ! scope="row" | 0xFF | ||
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== Rear fast threshold == | == Rear fast threshold == | ||
- | The nominal DAC setting is 0x45. | + | The nominal DAC setting is 0x45, which is ~20 keV. The step size is ~0.28 keV/step. |
[[Category: Tohban]] | [[Category: Tohban]] | ||
[[Category: Detectors]] | [[Category: Detectors]] |
Latest revision as of 18:08, 28 September 2015
The four thresholds – front slow, front fast, rear slow, and rear fast – are controlled by DACs that can be set from 0x00 to 0xFF (i.e., 0 to 255 in decimal). The slow thresholds were calibrated in detail prior to launch, but it is likely that the calibrations have drifted over time.
Contents |
Front slow threshold
Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x0C, which is ~3 keV.
DAC | 1F | 2F | 3F | 4F | 5F | 6F | 7F | 8F | 9F |
---|---|---|---|---|---|---|---|---|---|
0x0C | 2.68 | 2.66 | 2.58 | 2.82 | 2.61 | 2.51 | 2.32 | 2.63 | 2.52 |
0x10 | 3.49 | 3.44 | 3.32 | 3.59 | 3.40 | 3.26 | 3.09 | 3.42 | 3.25 |
0x20 | 6.68 | 6.55 | 6.27 | 6.66 | 6.57 | 6.27 | 6.15 | 6.58 | 6.19 |
0x40 | 13.1 | 12.8 | 12.2 | 12.8 | 12.9 | 12.3 | 12.3 | 12.9 | 12.1 |
0x80 | 25.9 | 25.3 | 24.0 | 25.1 | 25.6 | 24.3 | 24.5 | 25.6 | 23.8 |
0xC0 | 38.6 | 37.7 | 35.7 | 37.4 | 38.2 | 36.3 | 36.8 | 38.2 | 35.5 |
0xFF | 51.2 | 50.0 | 47.4 | 49.5 | 50.7 | 48.1 | 48.8 | 50.7 | 47.1 |
Front fast threshold
The nominal DAC setting is 0x22, which is ~6 keV.
Rear slow threshold
Here is a conversion table of selected DAC settings to keV according to the pre-launch calibration. The calibration is a linear function, and the nominal DAC setting is 0x30, which is ~20 keV.
DAC | 1R | 2R | 3R | 4R | 5R | 6R | 7R | 8R | 9R |
---|---|---|---|---|---|---|---|---|---|
0x30 | 24.1 | 23.4 | 24.0 | 24.3 | 24.5 | 23.9 | 20.8 | 19.0 | 21.1 |
0x40 | 27.3 | 26.4 | 27.2 | 27.6 | 27.5 | 27.1 | 24.6 | 22.5 | 24.1 |
0x80 | 40.0 | 38.5 | 40.1 | 40.5 | 39.7 | 39.8 | 39.9 | 36.6 | 36.0 |
0xC0 | 52.6 | 50.7 | 52.9 | 53.5 | 51.9 | 52.4 | 55.3 | 50.6 | 47.9 |
0xFF | 65.1 | 62.6 | 65.5 | 66.3 | 63.9 | 64.9 | 70.4 | 64.5 | 59.6 |
Rear fast threshold
The nominal DAC setting is 0x45, which is ~20 keV. The step size is ~0.28 keV/step.