PMTs

Pierre Auger Project

Progress Report

Malargüe has endured one of the most severe winters in many years. Snow, ice and very cold weather forced the suspension FD data taking and greatly restricted our deployment activities. The full text of the progress report graphically describes some of the difficulties at the Observatory caused by the weather.

Deployment of surface detector stations proceeded whenever the weather permitted. As of today (24 October) there are 1539 tanks deployed, 1495 have water and 1438 have electronics. Assembly and deployment of more stations has now stopped as we have exhausted our inventory of tanks. There are 160 tanks in Brazil waiting for transport to Malargüe. Funding problems and legal issues have been recently overcome so that we hope the first of these tanks will begin to arrive in next few weeks.

Because of the snow and rain there are a number of small areas that cannot currently be reached for deployment. Access may have to wait until late summer. The large (54 station) empty area in the array in front of Coihueco remains without an agreement with the owner and renter.

Good progress is being made on fabrication of equipment for the HEAT fluorescence telescopes. Everything is ready for construction to begin. Unfortunately agreement has not yet been reached with the owner of the 1000 square meters of land adjacent to Coihueco needed for installation.

The six detector stations that are part of the unitary cell for the AMIGA enhancement are now taking data. The muon counters associated with the unitary cell are in development.

Some particularly important news is that a letter describing one of our recent results has been accepted for featured publication next month in Science.

WBS 1.1.3 Fluorescence Detector Calibration (Jeff Brack – Colorado State University)

The FD calibration group was in Malargue in September.  Nine people were present, including collaborators from CSU, CU, IAFE, and PSU.  The primary goal of obtaining the initial absolute calibration for the Loma Amarilla telescopes was achieved, using the drum.  Analysis is now being completed, and calibration constants will be in the offline database soon.  New

flatfielding software was successfully used at Los Leones.  New gain settings were obtained, and the Los Leones cameras now have uniform response.  For Los Leones camera 4, measurements allowing absolute calibration of the low gain channels was made by masking off large

sections of the camera.

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

Andrej Filipcic and Marko Zavitanik:

The Coihueco PC was moved to Loma Amarilla and a new PC was installed in Coihueco. Smart UPSs were installed in Loma Amarilla and Los Leones.  All cabling for the Loma Amarilla Lidar was completed, and the PMTs will be mounted soon.

Roberto Mussa and Jorge Rodriguez:

The webcam was installed and cabled.  The video signal are ok, the serial connection still has problems.  The new RPCs were tested and their communication protocol was debugged.

The trigger lines to and from the FD are almost complete.  We currently only need the 25 V to 5 V adaptor, which Jorge will cable soon.

The cabling of all sensors needed for remote control was finished, with the exception of the light sensor to protect the PMTs, which is still missing.  The laser box was mounted on the frame and the frame was balanced.  Laser cabling and alignment, fiber pickoff cabling, and all other remaining tasks will be finished in November.

Two standard mirrors were mounted on positions 0 and 2 to help balancing.  The system  is ready for tests with the new Czech mirrors.  The tests are expected to be completed  right after the November meeting.  About 300 kg are available on site to counterweigh any test configuration we may want to try.

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

Shift participants: S. Harmsma (KVI), M. Kleifges (IPE), D. Maurizio (INFN-To, Lidar),

K. Payet (Grenoble), A. Schmidt (IPE), D. Tripadalli (USP)

With this report from the August 2007 shift to the collaboration I want to point out current problems we have to tackle and give some suggestion for improvements. I thank all shifters for their commitment in exceptional situations and their personal dedication. The report will essentially focus on unusual occurrences and problems (times are local Argentinean times):

· The shift started on Saturday August 4 and was scheduled to last till August 22 in the morning. During the first 2 nights the FD system was incomplete: the CAEN HV system was not working in LA due to preceding low temperature in the building. It is not totally clear, but most likely the computer and the screen didn’t boot due to condensation. The building was just heating up. Due to missing gas there was no heating in between the shifts. In addition, the cloud camera in CO (broken cable) was out of order the full shift and telescope #5 in LL failed during the first 3 days.

· In first night at 0:45 the communication to LM (but not the power) broke down. This is not a safety problem for the FD buildings, but the Lidar was in danger to be damaged as HV was still on and the cover can’t be closed without connection. Thus Daniela went with me to LM before the sun rise. Daniela could bring the Lidar in a save state (after getting the password for the computer from Italy) and I stopped the still running FD measurement (there were no T3 to CDAS, but the date was still saved locally). Finally a blown fuse was found as cause of the communication lost and fixed.

· The next days the shift went normally, i.e. with minor problems. Since August 10 the APF in Co was not working anymore, at least there were no APF events recorded. J. Matthews was informed, but there is no documentation for the shifters how to track down the problem by e.g. accessing the APF hardware. Other typical problems were the recovery from power failures. Either a curtain was hanging (blocking part of the aperture and had to be fixed by hand the next day) or other hardware parts were not starting properly leading to extra effort for the shifters.

· Adrian installed (with the help of H.J. Mathes) the code of the new TLT and from August 10-12, 2007 we recorded data in Co with telescopes 1, 3 and 5 for comparison with the old trigger. The new TLT algorithm was presented in the April 2007 Collaboration Meeting, but before applying it on every telescope we wanted to verify the operation in practise and measure the operation speed. Details on the new TLT will be published in a GAP note soon.

· As I have already reported in my mail (from Aug. 18) the shift was stopped from August 15 till the scheduled end August 22 due to intense snow fall followed by missing accessibility to the buildings. It started snowing at Aug.15 and continued for 3 days/night till Aug. 17. All FD sites were affected, the snow accumulated to about 30 cm in Malargue, 40-50 cm at the bottom of Coihueco and 30 cm in Loma Amarilla. In addition, several power cuts at Aug. 16 (early in the morning and during the days) in Malargüe and in the FD sites leaded to severe disruptions at CDAS; the UPS batteries discharged and had to be loaded before the SD system could be restarted after the RAID disk had been checked.

· FD was in standby during the power cut, thus all system survived with only minor damage. The heating for the shutter rails in LL #6 was defect and curtains in LL #1 /Co #6 were moving slowly thus producing a time-out in the SCS. The status of auxiliary monitoring systems like CLF, APF, Lidar and cloud monitor was not known at that time and the road conditions to the buildings were not known, either.

· Within the remaining time the shift crew tried to reach the buildings for inspection and free the Lidar roof from snow. Unfortunately, after the snow fall at the weekend 18./19. and at 20. August (official holyday in Argentina) there was no staff from the Observatory available. At first day it was very hard to reach LL, we had to stop at the bottom of the hill and walk up. My experience in the subsequent days was that obviously LA was best to reach, main problem for reaching LM was the slippery road (the mixture of water, sand and soil is like soft soap above freezing point and I got stuck on my way back) and Co was only reachable after a truck had luckily cleared the steep rising first part of the road. Surprisingly, the local roads inside Malargüe were cleared from snow (just a bit of ice) and also the road toward Sosneado. However, due to an accident the road towards San Rafael was closed at Sosneados for one day.

· The decision to suspend FD shift operation was made after discussion with Julio and others. Main argument was that the snow imposed an increased risk for reaching the building and that the collected data would be of bad quality due to missing atmospheric data (no APF, no cloud camera in some buildings, CLF was unclear, no Lidar).

Résumé:

At present state the FD system is far away from being operable at such severe weather conditions. As a first step I propose to improve the safety of the Lidar by installing an automatic closing of the enclosure at sun rise. The start-up procedure after power cuts should be revised (it contains too many traps and dependencies) and tested by simulated power cuts.

There are many new tools available for the shifters from the monitoring group, but it must be better documented before the shifters will make use of it. On the other hand, the shifters should give feedback by email to the responsible person and propose improvements for the handling. In any case the shift operation is much easier and the system is much more reliable than before.

WBS 2.1 SD (Ingo Allekote – CNEA)

In the period August - September 2007 the following tasks have been accomplished:

- Detectors assembled: 28, completing the assembly of all tanks available in Malargue.
- Detectors positioned in the field: 44
- Detectors filled with water: 53
- E-kits installed: 70

As of September 30th, 2007:

- Number of tanks in AB yard: 0
- Assembled detectors in AB yard: 18
- Total SD in the field: 1526
- Total SD with water: 1475
- Total SD with e-kit: 1430

Deployment and water delivery is continuing in the land owned by the Italians.

5 infill tanks were filled with water and e-kits were installed. Presently, a unitary cell of infill detectors is completely operational and taking data.

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

R&D for Auger North:

The Surface Detector electronics R&D for Auger North was discussed in a recent meeting (September 27-28) in Columbus, Ohio. The R&D is already in good progress for most of the SDE components. The current goal is to have prototypes for the 10 tank RDA array that is planned to be deployed mid-2008 at the Colorado site.

A new PMT design to get a significantly larger dynamic range for the Auger North PMTs is being studied in collaboration between IPN-Orsay and Photonis. The aim is to increase the dynamic range from 15 to more than 20 bit. This would allow the signal measurement close to the shower core (closer than 200 m even for the highest energies). The idea here is to use a profound dynode signal together with the anode signal from the PMT. First prototype is expected in a few weeks. A parallel solution for the large dynamic range would be to use an additional small PMT.

The FE-electronics is being developed in collaboration between IPN and LAL-Orsay. The current scheme has 3 different gains for each PMT channel. The different gain channels are internally calibrated. Figure 1 presents the scheme for the RDA array.

Figure 1: Scheme for the FE in the RDA array.

The overview of the FE board is presented in Fig. 2.

Figure 2: An overview of the FE-boards for the case where an additional small PMT is used.

The Unified Board, now called DAQ Board is being developed in APC. Figure 3 shows the board diagram.

Figure 3: Diagram for the DAQ Board.

The Cyclone III FPGA has been tested and shows good characteristics. It is currently proposed to use this chip for the digital trigger and for the GPS timing circuitry. Prototypes are expected for fall 2007 and 10 boards for the RDA array during 2008.

It was pointed out in the meeting that 10 additional DAQ boards are needed for the tanks that will be used only for telecommunication testing in the RDA array.

The PMT and electronics housing is currently being studied by LPSC-Grenoble. The aim of the R&D is to study if the PMT and electronics could be housed by a single unit, which would reduce the number of operations needed for installation. A photo of such unit is shown in Fig. 4. CSU will also join these R&D efforts.

Figure 4: PMT housing.

The tank power control board will be studied by KVI (Netherlands) in collaboration with the group of New Mexico.

For the moment it seems that the mid-2008 milestone for the RDA electronics could be met. However, efforts and new groups are still needed for the Surface Detector electronics R&D.

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

The Offline examples area has been split into to two new directories, one called ExampleApplications and one called StandardApplications.  The StandardApplications area is intended to document what configurations and module sequences are used for 'official' simulation, reconstruction and analysis tasks. One feature users may appreciate in

the new configuration is that no database connections are attempted unless the databases are actually needed by the application.  At the current time, these standard configurations and modules have not been reviewed  by the analysis teams, but are meant only to provide a

starting point.  The ExampleApplications area contains configurations and module sequences which may be experimental, not yet considered to be standard, or which may illustrate various perturbations of the configurations in the StandardApplications area.

The changes required to support multiple (simulated) triggers in the event have been completed and are merged on to the development trunk.These changes include modifications to the event structure as well as modifications to the TankGPSSimulator, TankTriggerSimulator and a new

module, CentralTriggerEventBuilder.

Development of a new SimulationCalibrator which generates the muon histograms is underway.  As a first step, all simulated calibration constants have been moved into the detector description, greatly simplifying the SD simulation sequences.  The new machinery also allows the possibility to employ different tank simulations in a single same event. (One might want to exploit this to speed up simulations of cases where the core is close to a station by employing a fast

parametrization for the station near the core).

High- and low-level interfaces to the cloud databases have been implemented.  We are not distributing the cloud data from the master database yet, but expect to do so shortly.

A new FTimeFitModel (GAP-2007-099) has been added to the repository, but is switched off until approved.

The LDFFinder has been updated so that the core position can be chosen to be either fixed to the MC truth, the hybrid estimate, or fitted.

The G4TankSimulator geometry description has been cleaned up making it easier to use for single tank studies, and the (in)famous hovering-above-the-ground problem has been resolved.

A new general-purpose histogram class has been introduced in the utilities area.

At long last, various fortran-related hurdles were overcome, and offline is working on OSX/Darwin systems.

We held a 2 week developer meeting in Karlsruhe at the end of September. As usual, minutes of the meeting are available on the wiki. During this time we consulted with grid experts and have developed a plan for grid-enabling offline software.   We also discussed and evaluated a number of new possible directions for development, including a more modern build system base on cmake, an interesting units package with dimensional checking, revisions to the Event Get/Make/Has protocol, long term strategies to reduce database usage during production, better

integration of the offline and ADST codes, and plans for graphical configuration and event display tools which are integrated in the framework.

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

August and September were not very good for FD data taking. The first of these shifts had to be suspended due to the worst snow storm of the winter. The second showed very short
visibility every night, mainly due to high winds and some fires in the field. This second issue should be solved as soon as we tell the landowners when they can or cannot burn their fields. This has already started, by giving them a schedule for the rest of 2007 and for 2008 with the dates when we are measuring with the FD. There were also some power outages that prevented normal operation in some buildings.

A new TLT algorithm was tested in August by A. Schmidt and M. Kleifges. The results were very good and will probably be reported soon in a GAP note.

WBS 9.0 Observatory Operations cont. – (Ricardo Sato – Southern Observatory)

Basically the problems during this period (2007/Aug and 2007/Sep) were generated by the weather condition, particularly on Aug 16th which had a quite heavy snow (about 50cm) which produce a power cut in Malargue during about 8 hours and all the data acquisition have been
stopped. The data acquisition system could only be recovered much later, about 30 hours later.

Although the cold weather in overall all period, there was some times which CDAS room had quite high temperature (close to 30 degree C). It happens because the air conditioner got freeze and could not work properly. During the summer this problem may became more frequently.
The batteries from Loma Amarilla tower used in the communication have been replaced and a system to charge batteries directly from generator has been installed. However there is a short communication lost when the power supply is switch between battery and generator.

Radio Detection R&D – (Ad Van de Berg – KVI)

The work on radio R&D with the setup from Leeds/OSU has now 2 out 3 stations running. additional work will be required to tune the hardware and software, especially regarding communications. Near the CLF, the team from France has 3 stations running. It seems there are problems with the electronics concerning the GPS time stamps for the radio data. A solution will be investigated with a frequent reboot of the DAQ systems. The wired systems near the BLS, operated by the team from the Netherlands, which uses an external trigger with plastic scintillators, is still running and producing data. However, because of power failures and bad weather conditions the up time has to be improved.

On September 17th and 18th on R&D meeting was organized by Charles Timmermans at the NIKHEF institute in Amsterdam.

HEAT enhancement -Hans Klages (FZK)

In August 2007 the contract for the HEAT site preparation was signed with the Camiletti company.

Unfortunately, the land owner has still not agreed to the lease contract.

Therefore, the Camiletti company cannot enter the site and start the earth movement.

We are trying hard to get the land owners signature asap. Many thanks to Alan and Jim for their effort!

In any case, installations at the HEAT site will be delayed considerably by the land access problems.

The second 40` container full of HEAT hardware is on its way to Argentina.

It will arrive in Malargue in the first week of November. Materials will have to be stored at the central campus.

Finally, a large part of the missing Italian funding for HEAT was approved (G. Matthiae).

Funds for the purchase of the additional PMTs for the HEAT cameras have been secured for 2008 in Germany (J. Bluemer). HEAT is now fully funded in 2007/2008.

For the AMIGA infill array tanks 140 PMTs and bases have been ordered.

This was enabled by a special grant achieved at Karlsruhe by M. Roth plus a substantial contribution from Wuppertal (K.-H. Kampert).

AMIGA - Alberto Etchegoyen

A very significant milestone has been reached in AMIGA because its 750m tank unitary cell is now routinely taking data which is been analysed. Temperature profiles are taken in a 3m deep well at the site. An integration and telecommunication prototype is already operational at the campus tank based on WiFi. A telecommunication WiFi concentrator prototype is being tested and assembled in Mendoza.

Efficiency was measured for 6 m long scintillator strips with either a 1.2 mm Kuraray or a 1.8 Bycron fiber. Both of them have 95% efficiency. A prototype 4-channel analog board has been assembled and tested and an 8-channel design is now being tested. FPGA design and simulations are under progress. A PMT testing facility is in progress based on a 64 - 4 channel multiplexor and a 4 channel 1 GHz 5.0 Gsample oscilloscope. A 350 m2 laboratory facility is finishing construction at Tandar.

PMTs, fibers, and scintillators for the muon counter unitary cell are shortly to be bought.