JLS Current Status

Date: 24 March 2008

TELESCOPE	Nothing to report.
SCUBA-2	The instrument has arrived at the JAC and the team from the UK ATC are also here in preparation for the Installation and Integration phase. SCUBA-2 will travel up to the summit to be lifted into the JCMT dome during the first week of April.
HARP/ACSIS	The current status of HARP/ACSIS is summarised below: H03: missing from the cryostat since delivery. H14: currently unusable due to large oscillations in the mixer. This receptor has now been switched off in the data acquisition and so will appear blank in the data and real time displays at the telescope. Receptors H09 and H12 are operational but have high resistance in series with the junction. For H09, this resistance has been present since the instrument was delivered. For H12, its high resistance appeared after a scheduled warm up in September. An interim solution has been to increase the bias voltage on these receptors. Bias settings were changed on the receptors in order to alleviate receptor-to-receptor variations. Some receptors now perform better, but others not so. For instance, H09 works well at 12CO but poorly at 13CO. This is because optimal bias settings are frequency dependent, e.g. variations are negligible around 370 GHz but they are worst at 330 GHz. We are looking into implementing a system where the bias level is set as a function of frequency, but this will take some time as the optimal bias settings for each receptor need to be determined across the frequency range. The cold head is due to be replaced during the April shutdown. It is hoped that this should cure the dewar temperature drifts that we have been seeing over the last few months.
CALIBRATION	A different method for reading the calibration loads has now been implemented which works more reliably.
JLS PROGRESS	The March JLS observing block was hosted by the NGS and was completed last week. See the summit occupancy page to see who the observers were. Part of this block was interrupted for eSMA commissioning resulting in 79 hours available of which 42.75 hours were used for JLS observing. The SLS obtained 5.7 hours of data, the GBS 9.35 hours and the NGS 27.7 hours of data. Quality assurance of this data by the teams is now needed. There were also 1.35 hours spent observing projects from the CN queue, 3.75 hours from the UK queue, 7 hours from the International queue and 19.15 hours on E&C work. The next observing block, also hosted by NGS, is due to start in April. Note that the telescope schedule for the rest of the semester has been finalised and teams should begin to organise their observers. The current progress is shown in the bar charts below, illustrating the amount of time charged to each survey and the current completion rate. With the assumption that all the data is accepted for the survey, the NGS is 95% of its way through its HARP allocation.
	For reference, the JLS allocations are given here.
ARCHIVED REPORTS	An archive of previous JLS status reports is accesible from the links below: 28 February 2008 15 February 2008 31 January 2008

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