PMTs

Pierre Auger Project

Progress Report

The FD shifts are becoming smoother. The shifts in June and July encountered only minor problems. The call for more collaborators to serve on FD shifts has brought a very gratifying response.

The construction of the last fluorescence building at Loma Amarilla is moving along well. Completion is expected in October. We hope to get access to the building in September to begin installing camera and mirror mounts and to mount shutters.

All of the materials and components to complete the Auger Observatory are either on site or on the way. The last of the tanks are being manufactured and are being shipped to Malargüe. Starting with about tank 700 there have been some pmts with unstable behavior. This has been a stubborn problem to solve. It appears now that the instability is due to the potting technique, possibility from capture of moisture or impurities in the silicone.

The deployment of tanks surface detector stations has fallen off dramatically. There are currently no positions available for deployment. One reason is the difficulty of access to parts of the array because of the high level of the water table this time of year. There are about 60 such positions. The other, larger problem is access to 367 positions on the lands of three owners in the north east part of the array. Negotiations with these landowners have been underway for several years. The CNEA and the Province of Mendoza are working hard to find a solution to the access problem. There has been important progress toward agreements in the last few weeks. Contracts with the owners containing most of the detectors have been prepared and the negotiations seem to be converging but they have not yet been signed. These last positions are the most distant from the Auger campus. In anticipation of the access to these positions we are taking steps to ensure that detectors and be installed as quickly as possible. We are, for example, moving completed detectors to a staging area in the north east part of the array.

The off-line data processing framework development is continuing. This work has benefited from the addition of more people to this task. Several papers both scientific and technical are in preparation.

WBS 1.1 Fluorescence Detector (Jonny Kleinfeller – Karlesruhe)

The shifts are running quite smoothly, there are only a few incidents which result in down time. In the last shift this was mainly due to a failure of the slow control PC at Coihueco.
Integration of the LIDARs has been improved. The computers are back in the CDAs room.

Currently all telescopes are being calibrated with the drum, I have been told, there are no problems with this task so far.
The progress of work at Loma Amarilla is within schedule. I am confident, some preparations for the installation of the telescopes can already be done in September.
Most components for Loma Amarilla are already in Malargüe, containers with missing parts have been dispatched from Germany (shutters) and the Check Republic (mirrors) and will arrive in August.

WBS 1.1 Fluorescence Detector cont. (Jan Ridky – FZU)

We have dispatched all the mirrors for Loma Amarilla, altogether 385 mirror segments for all 6 telescopes, spares included. At the moment they are somewhere on Atlantic ocean.

Shifts continue with increasing smoothness as the shifters are more experienced and the system is continuously improved.

WBS 1.1.3.3 Fluorescence Detector Atmospheric Monitoring (Stefan Westerhoff – Columbia)

R&D for 4th Lidar (reported by Juan Pallota)

The construction of a mechanical mount containing the mirror of the telescope has been finished; we also finished the system of the mirror subjection within this mount, the telescope arms and the positioning system of the optical fiber in focus. Pictures in the photo album show these components.

Tests of mechanical stability of the optical system have been made, to assure to us to fulfill the necessary requirements for the LIDAR system. For this, a mechanical assembly has been designed and constructed where the movements in zenith and azimuth can be simulated, in such a way we can try the constructed optics mounts, like in the real.

Because an optical fiber is placed in the center of the telescope, a coupling box is made to connect the optical fiber with a photomultiplier.

Inside of the box we find a lens that sights on the beam of the originating light of the optical fiber, through the filter and finally it enters the photomultiplier. The assembly is shown schematically in the following drawing:

We are improving at the moment the arms of the telescope, modifying its design and construction, to be able to surpass the obtained yield. We are still looking for a way of buying optical components from companies in the USA. We are also making the surface optical treatments of the telescope glass and finishing the mechanical structure that will attach the telescope to the platform of scanning. The bought components soon will be installed and set for the final test, to be able to take it to Malargüe in the month of September.

WBS 1.2 Fluorescence Detector digital electronics and readout systems (Matthias Kleifges – FZK-IPE)

Performance Monitoring

The Wuppertal groups organized an FD monitoring coding workshop from June 12-16. It was successful in

a) settling many of the remaining issues in format and structure of the PHP web pages,

b) completing the implementation for the filling of the monitoring database with the calibration information,

c) adding many of the missing or incomplete items (e.g. LIDAR and CLF) in the web pages,

d) addressing the integration into the general Auger Monitoring, and

e) setting up a tentative schedule till commissioning of the FD monitoring in November 06.

The page http://wiki.auger.org.ar/doku.php?id=fd:monitoring:wuppertal_meeting_jun06 hold more explicit documentation and the minutes.

Software progress

H.J. Mathes and A. Kopmann continued to improve the DAQ and related software, which is currently under test in Karlsruhe. The newest version FD-das-3.1.1-2 is ready for installation in Malargüe; the development for version FD-das-3.1.2-3 is started. In particular, post calibration activities initiated by the DAQ are needed within the FD monitoring scheme and are debugged.

There was a transition to a new built-system which makes all program code (GPS server, FDhwlib, FEshell, etc.) compatible with other (non Intel) computer architectures. A new monitoring software – the FEstatus daemon – is installed on the EyePC, which logs status changes of the front-end and checks the GPS clock periodically.

Hardware improvements

Within the last months following activities were performed:

We have started tests with alternative MPC to be installed in Loma Amarilla as the number of spares (current design) is to low for the full PAO lifetime.

We have procured KVM switches for the installation at each FD building. This allows monitoring the booting of EyePC and SC computer from the Campus from remote.

Together with our IK colleagues we have built more Auger LED models. The new models have enhanced programming options, i.e. they can display pre-programmed showers without a control computer connected.

R&D for Auger North and the HEAT proposal

A new prototype FLT board of the Auger North /HEAT design is under first test. These boards will be used to verify the bandwidth of the new backplane design as soon as the new backplanes are produced in September.

We have also produced more LCU units for the use with the HEAT proposal. For the new SLT design the FPGA programming is started and we are going to decide the required FPGA type soon.

WBS 2.1 SD (Ingo Allekote – Instituto Balseiro)

The numbers corresponding to this period are:

- Tanks received and inspected in Malargue: 54
- Detectors assembled: 31
- Detectors positioned: 34
- Detectors filled with water: 38
- E-kits installed: 23

As of July 31st, 2006:

- Total SD in the field: 1186
- Total SD with water: 1161
- Total SD with electronics kit: 984

The shipment of tanks (already made by Rotoplastyc and sitting in their yard) from Brazil to Malargüe has been a long struggle due to regulations regarding the dimensions of the load permitted on the Argentine highways. A trailer has been heavily modified by the trucking company, DiCanalli, in order to transport six tanks loaded in a horizontal position with a height and length within the legal requirements. This required replacing the wheels, suspension and axles of a (relatively) short trailer and mounting the six tanks with minimum vertical height using modified mounting fixtures. The new trailer arrangement is shown in the figures. This trailer with six tanks has left the Brazil-Argentina border and entered Argentina on the way to Malargüe. If this is successful, a second trailer will be modified in the same way and shipments will continue with twelve tanks per shipment. Production of tanks at Rotoplastyc has been stopped (due to lack of storage space) pending the successful shipment of the already-manufactured tanks to Malargüe.

Rotoplas continues to manufacture tanks and ship them at the rate of approximately 24 per month. They plan to complete the present orders (through UNAM) for 205 tanks by October. They have resin for an additional 24 tanks which have not yet been ordered. These additional tanks could be completed by the end of October.

Research on a molded-in foam layer has been performed extensively by Rotoplastyc in Brazil. The rotomolded foam layer for thermal insulation is of great interest for possible use in the Northern Observatory and prototype foam-insulated tanks are urgently needed for testing in both Malargüe and Colorado. Unfortunately, Rotoplastyc’s early success has not been reproduced. The technical representative of the resin company traveled to Rotoplastyc and worked with them to understand the process. He was not successful and is now working as rapidly as possible at their factory to try to find out what the problems are. Another resin company has been contacted about providing some resin for testing as well.

The batch of 180 batteries received at the beginning of June was extensively tested, as some of the first batteries tested showed an abnormal behavior. 150 batteries were tested (slope of the discharge curve at constant current in the linear regime) and all but 10 of them were found to be good for deployment.

A battery tester has been purchased and a solar panel system was set up in the AB yard for charging the batteries before test.

For the repair of water transport tank Tk-Delta, the provider sent a technician to solder some broken seams in the stainless steel tank and to reinforce the supports.

The detector Gonemito was suspected of having a water leak, so it was replaced and brought back to the central campus for inspection.

Negotiations with the three major landowners in the Northeast of the array are ongoing and some progress is being made towards reaching an agreement satisfactory for all parties involved (Auger, the landowners and the Province of Mendoza). Also, some pending contracts were signed with owners of small pieces of land in the La Junta area.

19 twin and triplet surface detectors were installed in the area near El Sosneado. As soon as batteries and electronics kits become available, these detectors will be put online.

For the Radio R&D efforts, poles were installed near the Balloon Launching Facility, for the deployment of radio antennas for Phase 1. Also, an infill detector was installed in this area and is expected to be put online soon.

WBS 2.2 Surface Detector Electronics (Tiina Suomijarvi – IPN Orsay)

SDE-Fabrica

The total number of Ekits assembled and tested is 1158. There are currently 135 Ekits ready for the field deployment. For further assembly there are 167 TPCBs and 88 Cyclone FE boards available. The last shipments were 198 FEs in the end of May and 216 TPCBs in the end of June. The next batch of 120 TPCBs is ready for shipment in CWRU. 64 FE3.3 from MTU and about 200 Cyclone FEs from Wuppertal are also ready for shipment.

The GPS test bench arrived few months ago. Training of the SDE staff to use the test bench is planned for November.

Electronics failure rates are low. The main problems are the UB fuses and some software problems (PROM1 and PROM4 need to be re-flashed sometimes). The 500 mA UB fuses are being replaced by 750 mA fuses. No problems have been detected for the moment with the UBs having 750 mA fuses.

PMT temperature instabilities

PMTs in tanks with id number larger than about 700 present instabilities as a function of temperature (see previous reports). These instabilities correlate with the PMT number and started for PMTs tested and potted after July-August 2004, before that only 4 PMTs have been detected with temperature instabilities. The appearance of instabilities coincides with a strong increase of testing and potting rate in the PMT-House (see figure below).

Figure: Number of PMTs tested per month as a function of time (red curve). Number of bad PMTs in each bin as a function of time (green dotted curve) (plot from Ricardo Sato).

Since no other correlation for the moment has been found (base fabricants, electronic components etc.), it is suspected that problems might be due to bad protection of the base against humidity. Several efforts have been made to increase the quality of the PMT potting (see previous notes). The PMT potting has been stopped since last March but will start again with a test batch of 72 PMTs (see below).

PMT-house

• PMTs received from Photonis: 5045 (including last shipment with Chinese glass)

• Tested PMTs: 3794

• Delivered PMTs: 3856 (3715 PMT Lab + 141 UCLA PMTs)

• PMTs waiting to be tested and potted: 1251

All PMTs are now stored in the SDE-Fabrica testing area where the humidity is lower than in the storage area (SDE test area about 26%, storage about 35%).

The SDE-Fabrica and PMT-house air condition will be improved to lower the humidity.

Plan for potting

• Pot carefully 72 PMTs that have been stored for more than 2 months in the SDEFabrica test area.

• Deploy these PMTs to the field to replace bad PMTs to get them quickly under monitoring (there are currently no tank deployment due to the land access problems).

• In the mean time, continue revising by experts the potting procedure.

• Test the bad PMTs from which the potting has been removed (3-4 PMTs).

• Pot again these PMTs and monitor their performance (in the black boxes and test tanks).

• Develop procedure for removing the potting.

• Test the PMT that was coated and potted.

• Next step: if coating+potting procedure is OK: coat and pot 72 more PMTs (including the Chinese glass PMTs) and deploy them to the field.

• Continue testing in laboratories (Grenoble, Torino, IPNO) and in the black boxes and test tanks on the site.

PMTs that are removed from the field are tested and stored in the SDE-Fabrica storage area. Only PMTs that have clearly a PMT problem (not base, potting or labels) are shipped to Photonis.

SDE deployment

There are currently only 26 places available for Ekits. More places will be available when batteries have been deployed. There is currently a batch of 180 batteries (90 tanks) in Malargue and another batch of 180 batteries should arrive in a week or so. The plan for SDE field operations during the next weeks is the following.

• Deploy the 72 PMTs potted with revised procedure (see above) to replace bad PMTs (high priority because we need to know if the revised procedure allows to lower the failure rate).

• Deploy Ekits when batteries are installed.

• Repair “black tanks”.

A major effort in field activities is required during the next few months. The number of field trips should be minimum 4-5 per week.

• SDE-Fabrica staff has accepted to help Javier and Fabien with the field work. People on shift should also participate to field trips.

• A second maintenance + installation truck should be bought together with some equipment necessary for two field trips at the same time.

WBS 4.0 Online Monitoring (Cyril Lachaud – APC)

A meeting has been organized by Pr. Kampert in Wuppertal for the FD/CLF part (http://fdmondev.dev.uni-wuppertal.de/~rautenbe/fdmon-wws/index.php). Discussions were oriented on the technical aspects as well as which variables to monitor, but coding sessions were taking most of the time. The FD/CLF groups are very active and has produced a huge amount of work.

On the following URI you can see the status of the project : http://fdmondev.dev.uni-wuppertal.de/daily/AugerMonitoring/WebSite/OBSERVATORY/

In Malargue, a dedicated MySQL server should be ready soon (Daumiller and Squartini). This server is a key for the development of the project.

You can find more informations on the project on the wiki pages http://wiki.auger.org.ar/doku.php (monitoring and fdmonitoring).

WBS 5.0 DPA/Offline- (Bruce Dawson, Markus Roth and Tom Paul)

In June, the Offline team held a 10-day developer meeting at the University of Nova Gorica. Details on the meeting agenda and a synopsis of the conclusions and plans are available here: https://www.auger.unam.mx/AugerWiki/NovaGoricaMeeting2006.

New members from Granada, Rome and Leeds were in attendance.

The integration testing framework from the Lecce group has been incorporated into the Offline development area. This system is being used together with the buildbot to run automatic checks of SD and FD reconstruction chains. Additional platforms and testing sequences have also been introduced into the buildfarm. Collaborators are encouraged to contribute a builder to the buildfarm, especially if they want to guarantee offline support on their favorite

platform. Details are available here: https://www.auger.unam.mx/AugerWiki/BuildBot

Work is in progress to link the FD calibration database to the web-based browsing tools developed by the Rome Auger Access group.

A number of improvements have been made in the SD simulation modules. The shower unthinning routines have been revised for more accurate treatment of the geometry and for better memory management in case of large numbers of particles. Configuration schemes for a number of simulation-related modules has been reorganized and/or simplified.

Events with stations falling inside the simulated shower inner radius cuts are now handled gracefully. A new very flexible particle injector module from the Northeastern group has been introduced. A more accurate description of the PMT geometry is being prepared for the tank simulators. The offline group is currently working to finalize a release intended for the next SD simulation production run. This is expected within about a week of the time of writing.

Work at Karlsruhe is nearing completion on a suite of improved FD simulation routines. Features include more user-friendly ray-tracing routines, a curved Earth option, 3D shower images and faster execution. In FD reconstruction, the Rome and Karlsruhe groups have been working to merge features of reconstruction from both groups. In particular, effort is engaged in implementing a spot-based reconstruction within the KG framework. Work continues in atmospheric corrections, with plans for multiple scattering corrections, and the propagation of aerosol parameter errors.

The SD reconstruction has been updated to use uncertainties in time and signal as given by the latest analyses of the sub-tasks.

WBS 9.0 Observatory Operations – (Julio Rodriquez Martino - INFN)

FD shifts during June and July presented no major problems. Only minor faults where found in the electronics and software. Curtains continue to fail from time to time, when they get stuck or the mechanism brakes. This happens far less frequently than before, but we still have two or three incidents per shift.

LIDAR continued to induce triggers in the FD during the shoot-the-shower mode. Possible solutions are under investigation.

Weather was generally good for running, with occasional rain or high speed winds.

A very nice hybrid event, with an energy close to 10²⁰ eV (or larger, depending on the calibration) was seen by Coihueco and the ground array. Regretably, being the

last night of the shift, Los Leones was closed due to the moonlight and Los Morados was also closed  due to dense fog that prevented normal data aquisition.

Images of the event are below. .