BTIs for the JEM-X Instruments complete up to Revolution 1330 (NB: In ISDCs BTI tables many periods spanning two revolutions, listed as separate BTIs here, are recorded as one long BTI) BTIs for Both JEM-X1 and JEM-X2 The following BTIs apply identically to both instruments Revolution BTI (IJD) Reason TOO observation of Swift J1727.8-1613 (LMXB with BH) swamps Xe line sot that gain determination is not verifiable during these periods. Also for many of these revolutions gain is well below 20 chans/keV for long periods. 2697 8686.8 IJD to 8687.55 TOO observation of Swift J1727.8-1613 2696 8685.45 to 8686.35 TOO observation of Swift J1727.8-1613 2695 8682.8 to 8683.65 TOO observation of Swift J1727.8-1613 2694 8678.6 to 8679.6 TOO observation of Swift J1727.8-1613 and gain below 20 chans/keV for much of this period. 2693 8677.45 to 8678.35 TOO observation of Swift J1727.8-1613 2692 8674.1 to 8674.6 TOO observation of Swift J1727.8-1613 - also gain is low for much of ths period 2691 8670.7 to 8671.8 TOO observation of Swift J1727.8-1613 2680 8642.7 to 8643.8 TOO observation of Swift J1727.8-1613 2678 8637.75 to 8638.5 TOO observation of Swift J1727.8-1613 JEM-X1 Revolution BTI (IJD) Reason 2690 8669.35 to 8669.9 TOO observation of Swift J1727.8-1613 2688 8662.8 to 8664.4 TOO observation of Swift J1727.8-1613 with very low gain throughout 2687 8661.1 to 8661.4 Gain suppression due to strong solar activity. 2686 8657.4 to 8658.2 Very low gain, presumably due to the strong solar activity 2685 8654.6 to 8657.2 Entire revolution has gain below 20 chans/keV 2684 8652.0 to 8654.6 Entire revolution has gain below 20 chans/keV 2683 8649.4 to 8651.9 Entire revolution has gain below 20 chans/keV 2682 8646.8 to 8649.2 Entire revolution has gain below 20 chans/keV 2681 8644.0 to 8646.6 Entire revolution has gain below 20 chans/keV 1862 6465.8 - 6466.5 Noise and gain suppression due to tail end of solar flare that kept instruments in safe mode for all of revolution 1861 1858 6456.8 - 6458.0 Huge gain suppression at the end of the rev. causes uncertain energy determination 1451 5357.9 - 5358.4 Forced telemetry breaks due to groundstation hand-over during renovations at Kiruna 1401 5207.0 - 5208.1 Solar activity that forced all instruments to go to SAFE mode 1400 5204.0 - 5205.8 Solar activity that forced all instruments to go to SAFE mode 1389 5170.5 - 5173.5 More solar activity and non-linear gain suppression 1388 5169.1 - 5170.9 Solar activity caused roughly 30% drop in gain and significant non-linear effects that couldn't be corrected in the time available. 1372 5120.3 - 5123.2 Most of revolution instruments switched off. A handful of SCWs all with extreme gain suppression, before switching off again. 1371 5119.35 - 5120.2 Beginning of long period of solar activity - precipitous gain suppression 1339 5021.4 - 5023.3 Solar flare during which instruments put in safe mode 1319-1324 All instruments shut down during SPI annealing 1295 4890.5 - 4892.9 Instruments in SAFE mode due to solar activity for most of revolution 1293 4883.9 - 4886.9 Solar activity depresses gain to historically low levels disrupts not only gain response of instruments but loses lots of events to the low-level discriminator 1281 4849.2 - 4850.0 M-class flare 1273 4824.1 - 4824.7 Flare problems at beginning of revolution 1255 4772.04 - 4722.18 Short BTI due to heavy grey-filtering cutting down calibration spectra 1242 4731.8 - 4732.6 Disruption of energy calibration due to solar flare 1208 4629.7 - 4630.5 Suggested BTI to cover first 1/4 of the revolution 1207 4627.6 - 4629.7 High countrate with strong gain suppression due to solar activity 1192 4583.35 - 4584.8 CME with strong suppression of gain due to high countrate 1190 - 1191 4576.8 - 4579.65 Solar activity with gain suppression due to high countrate BTI covers end of rev. 1190 and beginning of 1191 1171 4521.0 - 4522.0 Settling period after recovery from autonomous shutdown due to solar activity (high countrate) 1148 - 1149 4449.0 - 4456.3 Both revolutions strongly affected by solar activity 1133 - 1135 4405.4 - 4414.4 Revolutions affected by strong solar activity 1113 - 1114 4347.7 - 4349.1 End of 1113 and beginning of 1114 badly affected by strong solar flare 1019 4066.5 - 4067.5 Non-standard electronic configuration 977 3938.8 - 3938.9 Switch on with rapid gain settling 976 3935.8 - 3936.4 Switch on after long dormant period 967 3908.8 - 3909.2 Switch on with rapid gain settling 966 3905.8 - 3906.4 Switch on after long dormant period 914 3750.3 - 3750.6 Switch on with rapid gain settling and high gain 913 3747.3 - 3737.6 Switch on with rapid gain settling and high gain 912 3744.3 - 3744.5 Switch on with rapid gain settling and high gain 911 3741.3 - 3741.8 Switch on after long dormant period 903 3717.4 - 3718.0 This unit switched on for crab calibration after long dormant period 483 2463.05 - 2463.07 1 kSec period with only one anode segment switched on 422* 2280.57 - 2280.61 HV lowered for efficiency test 2280.84 - 2280.96 " " " " " 370* 2125.43 - 2125.56 No calibration source data during tests with HV settings 365* 2110.22 - 2110.33 HV lowered for efficiency test during crab calibration 276 1842.0 - 1843.0 Whole revolution (very little actual data); high background; gain suppression on plate. 262* 1801.45 - 1801.57 Gas contamination testswith variable VC voltage 260 1796.20 - 1796.40 Incorrect HV value at switch on 207* 1635.70 - 1636.59 CPU erroniously in 8 MHz mode 206* 1632.70 - 1635.39 " " " " " " 167 1516.50 - 1516.70 Short test activation during long dormant period. Loading new selection criteria 15* 1061.42 - 1062.77 Discriminator test Before Rev. 15 All SCWs/REVs Different onboard binning from rest of mission used due to higher gain before HV reduction to control microstrip burnout JEM-X 2 Revolution BTI (IJD) Reason 2690 Entire revolution JEM-X2 switched off during revolutions with TOO observation of 2689 Entire revolution Swift J1727.8-1613 (LMXB with BH) to give extra TM packets 2688 Entire revolution to JEM-X1 2687 Entire revolution All these revolutions do not appear on the BTI table because 2686 Entire revolution there's no science data to process, but users should be aware 2685 Entire revolution of the reason why OSA skips over these revolutions for JEM-X2 2684 Entire revolution 2683 Entire revolution 2682 Entire revolution 2681 Entire revolution 1977 6771.5 - 6772.15 JEM-X1 was switched on after JEM-X2 due to problems in the previous revolution, so there is no calibration data for the JEM-X2 unit at the beginning of the revolution. Problem is compounded by the BTI happening during the JEM-X2 settling period that is difficult to correct at the best of times. 1862 6465.8 - 6466.5 Noise and gain suppression due to tail end of solar flare that kept instruments in safe mode for all of revolution 1861 1858 6456.8 - 6458.0 Huge gain suppression at the end of the rev. causes uncertain energy determination 1401 5207.0 - 5208.1 Solar activity that forced all instruments to go to SAFE mode 1400 5204.5 - 5205.1 Solar activity that forced all instruments to go to SAFE mode 1389 5170.5 - 5173.5 More solar activity and non-linear gain suppression 1388 5169.1 - 5170.9 Solar activity caused roughly 30% drop in gain and significant non-linear effects that couldn't be corrected in the time available. 1372 5120.3 - 5123.2 Most of revolution instruments switched off. A handful of SCWs all with extreme gain suppression, before switching off again. 1371 5119.35 - 5120.2 Solar activity causes plunge in gain before automatic shutdown 1339 5021.4 - 5023.3 Solar flare during which instruments put in safe mode 1319-1324 All instruments shut down during SPI annealing 1295 4890.5 - 4892.9 Instruments in SAFE mode due to solar activity for most of revolution 1293 4883.9 - 4886.9 Solar activity depresses gain to historically low levels disrupts not only gain response of instruments but loses lots of events to the low-level discriminator 1281 4849.2 - 4850.0 M-class flare 1273 4824.1 - 4824.7 Flare problems at beginning of revolution 1255 4772.04 - 4722.18 Short BTI due to heavy grey-filtering cutting down calibration spectra 1242 4731.8 - 4732.6 Disruption of energy calibration due to solar flare 1208 Suggested BTI to cover first 1/4 of the revolution 1207/1208 4627.6 - 4630.5 High countrate with strong gain suppression due to solar activity 1192 4583.35 - 4584.8 CME with strong suppression of gain due to high countrate 1190 - 1191 4576.8 - 4579.65 Solar activity with gain suppression due to high countrate BTI covers end of rev. 1190 and beginning of 1191 1171 4521.0 - 4522.0 Settling period after recovery from autonomous shutdown due to solar activity (high countrate) 1148 - 1149 4449.0 - 4456.3 All revolutions strongly affected by solar activity 1133 - 1135 4405.4 - 4414.4 Revolutions affected by strong solar activity 1113 - 1114 4347.7 - 4349.1 End of 1113 and beginning of 1114 badly affected by strong solar flare 1019 4066.5 - 4067.5 Non-standard electronic configuration 950 3858.00 - 3858.60 Very short activation period with poor gain determination due to high countrate when SCO X-1 appeared unexpectedly in the FOV 856 3576.8 - 3577.2 Switch on with strong settling 797 3400.3 - 3401.2 Strange gain behaviour not understood at all 796 3397.3 - 3397.8 Switch on after long dormant period 774 3331.4 - 3332.0 Switch on after long dormant period 714 3152.2 - 3152.5 Switch on after long dormant period 666 3008.6 - 3008.9 Switch on of instrument after long dormant period Very large settling effects 605 2825.8665 - First 24 SCWs of revolution 2826.53187 erroneously processed onboard with wrong PHA binning table due to MOC activation error. 541 2634.50 - 2634.80 Extremely rapid gain variation after switch on after long dormant period 2634.8 - 2635.2 Rapid gain variation and bad response 2635.70 - 2636.10 Engineering exercises during Crab calibration 483* 2460.80 - 2463.80 Engineering tests with old S/W image uploaded 482* 2457.90 - 2460.80 Switch on after long dormant period; wrong S/W image uploaded; engineering tests. 422* 2280.57 - 2280.61 HV lowered for efficiency test 2280.84 - 2280.96 " " " " " 421 2275.50 - 2275.90 Activation after long dormant period, prior to Crab calibration 399 2209.90 - 2210.40 " " " " " causes large and rapid gain settling period 365 2110.00 - 2111.00 Very short Crab calibration with changes in HV values, during long dormant period 300 1913.80 - 1914.30 Switch on after long dormant period, prior to Crab calibration Huge gain settling period 239 1731.20 - 1731.70 " " " " " 208 1638.60 - 1639.30 " " " " " 179 1553.50 - 1553.90 Experimental activation during long dormant period 173 All Short activation for loading of new selection criteria 171 And onwards JEM-X2 put to sleep while JEM-X1 becomes work unit 134 1419.53 - 1419.74 Calibration events in Sci. stream not available in HK as usual. 15* 1061.42 - 1062.77 Discriminator test Before Rev. 15 All SCWs/REVs Different onboard binning from rest of mission used due to higher gain before HV reduction to control microstrip burnout REASONS FOR BAD TIME INTERVALS: 1) Engineering windows, usually during Crab Calibrations, during which non-standard instrument settings are tried out 2) Very early revolutions during which deprecated data formats were common; FULL is the approved standard. REST; SPEC and TIME data formats are deprecated and none of the later OSA software supports these data formats 3) Reactivation of an instrument that has been dormant for many weeks or months - gain-settling period will be a BTI 4) Periods of intense solar activity where instruments are either shut down, or behaving poorly prior to being shut down. 5) Periods of very high background with strange gain variations and gain suppression leading to reduced event flux Where gain is below 20 channels/keV the period is generally declared a BTI. This usually happens at the beginning of reach revolution, so these periods are not recorded on the BTI tables, but OSA10 and later skips automatically over the first part of each revolution where gain is changing rapidly and unevenly across the microstrip plates. 6) JEM-X2 settling period where there is no JEM-X1 calibration data to work with (very rare). This page is maintained by Carol Anne Oxborrow. If you think it needs further updates, or have any comments or queries at all, please contact me at: oxborrow "at" space.dtu.dk