From sommers@physics.utah.edu Wed Oct 4 17:11:15 2000 Received: from fusion.physics.utah.edu (fusion.physics.utah.edu [128.110.200.144]) by top.physics.utah.edu (8.9.2/8.9.2) with ESMTP id RAA33136; Wed, 4 Oct 2000 17:11:10 -0600 Received: (from sommers@localhost) by fusion.physics.utah.edu (8.9.2/8.9.2) id RAA23513; Wed, 4 Oct 2000 17:11:01 -0600 (MDT) Date: Wed, 4 Oct 2000 17:11:01 -0600 (MDT) Message-Id: <200010042311.RAA23513@fusion.physics.utah.edu> X-Authentication-Warning: fusion.physics.utah.edu: sommers set sender to sommers@physics.utah.edu using -f From: Paul Sommers To: etchegoy@tandar.cnea.gov.ar, kampert@ik1.fzk.de, Camin@mi.infn.it, MANTSCH@FNAL.GOV, hojvat@rdiv.fnal.gov, Dawson@physics.utah.edu, shellard@lafex.cbpf.br, fick@casa.physics.utah.edu, ingo@cab.cnea.gov.AR CC: sommers@physics.utah.edu Subject: Coihueco vs Puntilla Status: R Replies from Brian Fick, Ingo Allekotte, and Bruce Dawson so far. *********************************************************** From: "Observatorio Pierre Auger" To: Cc: , "Gibbs 1" Subject: FD sites Date: Thu, 28 Sep 2000 17:07:05 -0300 Hola Pablo, Ingo, Ken, and I have been mulling over the choice of Puntilla vs Coiheco for FD site number 2. It is true that the simulations performed by Ron Shellard and myself turned up some minor differences in potential performance for the two configurations. As I recall, the Puntilla choice favored stereo performance whereas the Coihueco choice favored performance without a central detector. But both results were at the 5% (or less) level, well within the uncertainties of the simulations. There was no clear favorite. It therefore appears that we must make a decision based on something other than estimated performance. There is one exception to this which has to do with comms performance. Tests which were performed at both sites indicated that Coihueco perfoms much better than Puntilla. An antenna at Coihueco can very probably cover the area of the array covered by the central antenna. We might be able to save some money by installing something simpler at the central site which just handles the FD comms requirements. How do the two sites compare in regard to darkness? Both exist in a generally dark environment. However, Puntilla suffers from relatively nearby Hg vapor lamps (10 km line of site) from a natural gas station in the center of (but below) its field of view. Coihueco has the town of El Sosneado immediately to the north. But the lights of the town are relatively dim and are not in the field of view. The existence of bothersome local sources is not necessarily eternal, however. It is always possible to negotiatiate with the owners for a change to sodium vapor lamps or the installation of strategically placed baffels. But the effectiveness of these negotiations always carries some uncertainty. We cannot force anyone to do anything. Is one site more expensive to construct and maintain than the other? Roadways to both sites, which must be in part constructed and improved are estimated to cost approximately the same for both configurations. Puntilla is flatter and thus easier to deal with but will probably be a bit longer (5km compared with 4km) compared with Coihueco. Coihueco will require some sophisticated construction items such as the installation of culverts over some large washouts. The major difference between the two sites is with power distribution. As presently understood, the nearest source of grid electric power for the Puntilla site is in El Sosneado, some 20 km distant. The Coiheuco site can obtain its power from the line running along the road at the base of the hill. The maximum distance would be about 2 km. Recall that the Los Leones power line (14 km) costs about $270K. Perhaps $50K of this was applied to the cost of tranformers etc common to any given hookup. So the lines and poles cost about $16K per km. So the site-unique costs for power to Puntilla is about $320K while to Coihueco it is perhaps $32K. To first order, the difference in grid power installation costs for the two sites could construct an FD building! Even if we chose to use local generators for the power, the cost of grid power to Coihueco would be less expensive because of the short line run. In conclusion, let me summarize the situation. It is difficult to make a choice between the two sites based on simulated performance, environmental factors such as local light pollution, or the relative cost of constructing roads to the two installations. However, Coiheco clearly wins over Puntilla when it comes to communications coverage. And most importantly the cost of providing electric power to Puntilla site is significantly greater than for the Coiheco site. We therefore recommend that the Coiheco site be adopted as the next FD detector location. ciao, -Brian Fick ***************************************************************** >From auger@slatinos.com.ar Fri Sep 29 19:36:38 2000 To: "Paul Sommers" Cc: "Gibbs 1" , , , "Norberto Fazzini" Subject: Coihueco vs Puntilla Date: Fri, 29 Sep 2000 22:10:10 -0300 Dear Paul, I still owe you some answer regarding the Coihueco-Puntilla debate. Brian already gave some arguments, let me add specifically the landowners subject: Coihueco is owned (according to telephonic information, we should do more serious research about it) by the Las Lenias Complex, who have a positive attitude towards Auger, although they have not signed anything yet (apparently, because it was not clear who was the person entitled to sign such contracts). The highest point of Puntilla is owned by a "puestero", a very modest man living up there, not far from the road. He has not been contacted yet. His land is not too big. Other, lower points of Puntilla, might have other owners, we should find out in detail (though this might take some time). So, in a first order approximation, I would guess that negotiations will be easier with Coihueco owners. Additionally, there seems to be some problem with one of the owners just in front of Puntilla (Raul Chacon). If this problem persists, Coihueco is definitely a better choice. Regards, Ingo. *************************************************************** >From bdawson@physics.adelaide.edu.au Tue Sep 26 19:28:05 2000 Date: Wed, 27 Sep 2000 10:57:48 +1030 (CST) From: Bruce Dawson To: Paul Sommers Regarding the Coiheco/Puntillas comparison. I think (correct me if I'm wrong) that the only sims done so far on this are by Ron (perhaps Brian did some too?). If Ron's are the only ones, I should either encourage him to do new ones with his new improved MC, or I should do some with the old MC. If I'm not mistaken, his original sims on the comparison were done with the so-called fast FDSim, which has some deficiencies, including monochromatic fluorescence light. all the best, Bruce ---------------- Dept. of Physics and Mathematical Physics Phone:+61 8 8303 5275 The University of Adelaide FAX: +61 8 8303 4380 Adelaide, 5005, AUSTRALIA bdawson@physics.adelaide.edu.au Treasurer, Astronomical Society of Australia From bdawson@physics.adelaide.edu.au Wed Oct 4 17:35:28 2000 Received: from adelphi.physics.adelaide.edu.au (adelphi.physics.adelaide.edu.au [129.127.36.1]) by top.physics.utah.edu (8.9.2/8.9.2) with ESMTP id RAA27202; Wed, 4 Oct 2000 17:35:23 -0600 Received: from bruce.physics.adelaide.edu.au (bdawson@bruce [129.127.36.58]) by adelphi.physics.adelaide.edu.au (8.8.8/8.8.8/UofA-1.5) with ESMTP id JAA21446; Thu, 5 Oct 2000 09:05:20 +0930 (CST) Date: Thu, 5 Oct 2000 09:05:18 +1030 (CST) From: Bruce Dawson To: Paul Sommers cc: etchegoy@tandar.cnea.gov.ar, kampert@ik1.fzk.de, Camin@mi.infn.it, MANTSCH@FNAL.GOV, hojvat@rdiv.fnal.gov, Dawson@physics.utah.edu, shellard@lafex.cbpf.br, fick@casa.physics.utah.edu, ingo@cab.cnea.gov.AR Subject: Re: Coihueco vs Puntilla In-Reply-To: <200010042311.RAA23513@fusion.physics.utah.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: R Hi Paul et al, Further to my last email about the Coihueco vs Puntilla question. Mainly because I couldn't clearly remember the results from Ron and Brian's simulations, I have run more triggering and reconstruction simulations comparing the two options. I will write this up in the next few days as a permanent record. Confirming Brian's comments in his recent email, there isn't much of a difference, either in the triggering or the reconstruction quality. I haven't yet knocked out the central eye to see the effect, but I will do so. all the best, Bruce ---------------- Dept. of Physics and Mathematical Physics Phone:+61 8 8303 5275 The University of Adelaide FAX: +61 8 8303 4380 Adelaide, 5005, AUSTRALIA bdawson@physics.adelaide.edu.au Treasurer, Astronomical Society of Australia From shellard@lafex.cbpf.br Fri Oct 6 15:46:19 2000 Date: Fri, 06 Oct 2000 18:30:10 +0100 From: shellard Organization: LAFEX/CBPF X-Mailer: Mozilla 4.72 [en] (WinNT; I) X-Accept-Language: en,pt-BR MIME-Version: 1.0 To: Bruce Dawson CC: Paul Sommers , etchegoy@tandar.cnea.gov.ar, kampert@ik1.fzk.de, Camin@mi.infn.it, MANTSCH@FNAL.GOV, hojvat@rdiv.fnal.gov, Dawson@physics.utah.edu, fick@casa.physics.utah.edu, ingo@cab.cnea.gov.AR Subject: Re: Coihueco vs Puntilla References: Content-Type: multipart/mixed; boundary="------------11429A32DE1787CDB5A22713" This is a multi-part message in MIME format. --------------11429A32DE1787CDB5A22713 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hi Paul, Bruce and all, Here goes a copy of the transparencies which we presented in Malargue on the comparison of site alternatives (they are *.jpeg with winzip compression. If you have trouble opening them I can send it compressed with gzip). The second slide has the positions for the eyes in a schematic view, except for the Puntillas eye. I took the position of the eyes from the very detailed map Ken put in the web a long time ago, including the sugestion of the position of the central eyes. What we call "Standard" is the normal configuration, with a diaphragm with 85 cm radius. What we call "Large" is a config with the telescopes diaphragm with double effective area than the "Standard". The Cohieco and Puntillas are made with 4 eyes each Cohieco or Puntillas, Los Leones, Los Morados and the Central Eye. What we call Peripheral configuration has: Los Leones 6 telescopes Los Morados 6 telescopes Coiheco 6 telescopes Peripheral Eye 5 telescopes all with a large diaphragm, that is with double effective area. That presumes that corrector lenses work well. All plots refer to fraction of showers falling within the array area (we simulate the ones falling outside as well but have not shown it). On the last plot we show the impact of different aerosol attenuation conditions on the Peripheral Configuration. As it is mentioned in the summary, the comparison between the two standard configurations (Cohiecos and Puntillas) can vary slightly moving around the central eye. But we fell strongly that the decision between which configuration to choose should depend much more strongly on other local factors, like access, light nearby, cost, etc... From the "geometric" point of view they are quite equivalent. If there is the feeeling that a more detailed analysis is called for, we can do it fast. Cheers, Ron