Difference between revisions of "Run Coordinator report: Fall 2018 w12"
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| − | The GlueX experiment in Hall D was scheduled for 152 hours of beam, but received only 87.3 hours (57%). We could use about 80.8 hours (ABU) or 53% of the scheduled beam time. Major causes for down time on our side were a readout failure of the 5C11B beam position monitor (~2h), a period during which our slow control system (CSS/EPICS) was not responsive (~2h) and the scheduled installation of a new 10 inch beam pipe for the Compton Calorimeter (~8h, during beam studies). The remaining losses can be attributed to configuration changes. So far, the experiment ran for 86% of the scheduled fall 2018 beam time and collected 67% of the total data expected for this period. | + | The GlueX experiment in Hall D was scheduled for 152 hours of beam this week, but received only 87.3 hours (57%). We could use about 80.8 hours (ABU) or 53% of the scheduled beam time. Major causes for down time on our side were a readout failure of the 5C11B beam position monitor (~2h), a period during which our slow control system (CSS/EPICS) was not responsive (~2h) and the scheduled installation of a new 10 inch beam pipe for the Compton Calorimeter (~8h, during beam studies). The remaining losses can be attributed to configuration changes. So far, the experiment ran for 86% of the scheduled fall 2018 beam time and collected 67% of the total data expected for this period. |
This week was dedicated to a special measurement of cross sections at lower energies, in order to overlap with previous measurements from CLAS and obtain a better understanding of systematic uncertainties. For this purpose, the current in the PS magnet was reduced from 910A to 400A which shifted the PS acceptance to the region between 3 and 5.5 GeV. The tagger hodoscope counters in this energy region were turned on, which limited the acceptable beam current to 40nA. We decided to take 40% of the data with an amorphous radiator (trigger rate ~9kHz) and 60% with the 47mum diamond radiator (trigger rate ~13kHz). For the latter, the coherent edge was shifted down to 7GeV, producing a peak polarization above 60%. | This week was dedicated to a special measurement of cross sections at lower energies, in order to overlap with previous measurements from CLAS and obtain a better understanding of systematic uncertainties. For this purpose, the current in the PS magnet was reduced from 910A to 400A which shifted the PS acceptance to the region between 3 and 5.5 GeV. The tagger hodoscope counters in this energy region were turned on, which limited the acceptable beam current to 40nA. We decided to take 40% of the data with an amorphous radiator (trigger rate ~9kHz) and 60% with the 47mum diamond radiator (trigger rate ~13kHz). For the latter, the coherent edge was shifted down to 7GeV, producing a peak polarization above 60%. | ||
| − | We started the low-energy program on Wednesday, when we recorded a TAC run to determine the PS acceptance. Around 11pm, we started our first low energy run and continued this program until Monday morning. Even though the accelerator was down for more than 20 hours | + | We started the low-energy program on Wednesday, when we recorded a TAC run to determine the PS acceptance. Around 11pm, we started our first low energy run and continued this program until Monday morning. Even though the accelerator was down for more than 20 hours due to a HV issue in RF cavity 1L23 over the weekend, we managed to collect 2.3B triggers for the special low-energy data set while cycling through the different radiator orientations 6 times. This corresponds to about 116% of the previously defined goal. |
| − | The scheduled system recovery period on Monday was used for preparations | + | The scheduled system recovery period on Monday was used for preparations for the installation planned for Tuesday, for FCAL maintenance and for investigations on the liquid hydrogen target. In addition, an upgrade to Hall D current locks was performed. Unfortunately, the beam was not available during the night. On Tuesday, a new beam pipe was installed in preparation for the Compton Calorimeter for PrimEx. On Tuesday evening, all settings were restored and the standard production running was resumed. |
Latest revision as of 16:48, 16 November 2018
The GlueX experiment in Hall D was scheduled for 152 hours of beam this week, but received only 87.3 hours (57%). We could use about 80.8 hours (ABU) or 53% of the scheduled beam time. Major causes for down time on our side were a readout failure of the 5C11B beam position monitor (~2h), a period during which our slow control system (CSS/EPICS) was not responsive (~2h) and the scheduled installation of a new 10 inch beam pipe for the Compton Calorimeter (~8h, during beam studies). The remaining losses can be attributed to configuration changes. So far, the experiment ran for 86% of the scheduled fall 2018 beam time and collected 67% of the total data expected for this period.
This week was dedicated to a special measurement of cross sections at lower energies, in order to overlap with previous measurements from CLAS and obtain a better understanding of systematic uncertainties. For this purpose, the current in the PS magnet was reduced from 910A to 400A which shifted the PS acceptance to the region between 3 and 5.5 GeV. The tagger hodoscope counters in this energy region were turned on, which limited the acceptable beam current to 40nA. We decided to take 40% of the data with an amorphous radiator (trigger rate ~9kHz) and 60% with the 47mum diamond radiator (trigger rate ~13kHz). For the latter, the coherent edge was shifted down to 7GeV, producing a peak polarization above 60%.
We started the low-energy program on Wednesday, when we recorded a TAC run to determine the PS acceptance. Around 11pm, we started our first low energy run and continued this program until Monday morning. Even though the accelerator was down for more than 20 hours due to a HV issue in RF cavity 1L23 over the weekend, we managed to collect 2.3B triggers for the special low-energy data set while cycling through the different radiator orientations 6 times. This corresponds to about 116% of the previously defined goal.
The scheduled system recovery period on Monday was used for preparations for the installation planned for Tuesday, for FCAL maintenance and for investigations on the liquid hydrogen target. In addition, an upgrade to Hall D current locks was performed. Unfortunately, the beam was not available during the night. On Tuesday, a new beam pipe was installed in preparation for the Compton Calorimeter for PrimEx. On Tuesday evening, all settings were restored and the standard production running was resumed.
