Dear Xiaochao, We have a few press molds for lead and molds for scintillator in Protvino, which can use for production prototypes. It is: a) the COMPASS mold for scintillator with size 38x38mm**2; b) two COMPASS press molds for lead with size 38x38mm**2 and 76x76mm**2; c) the COPIO mold for scintillator with size 110x110mm**2 and also press mold for lead with the same size. We can build a prototypes using COMPASS equipment with 1.5mm scintillator thickness and with sizes: 38x38mm, 76x76mm, 114x114 and 152x152mm and with lead 0.5mm thickness; also using COPIO equipment with 1.5mm scintillator thickness and 110x110mm size with lead 0.55mm thickness. All materials and tools for reasonable prototype are exist. The prototype, without preshower, can produced during 2 months. I have scintillator plates with thickness 10mm. During one month, we can produced and tested few samples of scintillator for preshower with 100x100mm. The number of photoelectrons and uniformity can measured. Best regards, Vladimir. ________________________________________ From: Vladimir Polyakov Sent: 17 December 2012 16:44 To: Xiaochao Zheng Cc: Zhiwen Zhao; Mehdi Meziane; Jin Huang; vladimir polyakov; polyakov@mx.ihep.ru; sergey.donskov@ihep.ru; donskov@ihep.ru; jpchen@jlab.org Subject: RE: Electromagnetic Calorimeter Design for JLab SoLID Project Dear Xiaochao, I am sorry for long silence, I was sick one month and also was busy at shift on OKA experiment on IHEP accelerator. However, I've spent considerable time on your project, and I can definitely answer on significant part of your questions. As you know all CERN accelerators will stop until autum of 2014, and COMPASS experiment also. In principle, I can spend more time for SOLID project. I. Preshower: Now, the preshower are placed inside calorimeter module. In this version exist significant disadvantages: complicated construction of calorimeter module, new untested design for calorimeter module and cost increase. Of course it's possible to produce but exactly will need a test few prototype. In slide 7, page 2 (your attached file with EC design) shown calorimeter with preshower. Between preshower and Shashlyk should be gap 30 or 40mm for bend preshower fiber. Also length of light guide, 100mm in slide, can be reduce on 30-40mm, if shower WLS fibers collect in four optical connectors. In this case 100x100mm**2 module and 50x50mm**2 module will uses the same connectors and the same equipments can be use for assemble. Would you examine to build two independent detectors, preshower and calorimeter with independent support structure, like in LHCb? In this case, lead converter can build from few large pieces, that will simple and cheap. All read out fibers can be easy send to the side of detector, also LHCb expirience can be use. Also in LHCb preshower detector consist of two layers of scintillator pads separeted by lead plate. First layer of scintillator pads placed in front of lead convertor use for photons/electrons separation. Do you need photons/electrons separation? Can you reduce a thickness scintillator in preshower from 20mm to 12mm or 10mm? The fact is that 20mm scitillator with size 10x10cm**2 can't be produce by the injection molded technique in IHEP. I discussed this question with Sergey Chernichenko, he is head of scintillators subdivision. But it's possible for 12mm and exactly for 10mm thickness. As I understand for preshower will be need 25-30 photoelectrons for MIP, I think that this light yield can be achieved with 10mm scintillator. Price estimation for preshower scintillator with size 100x100mm**2 and thickness 10mm (100g weight): Version A (production scintillators using the process of styrene polymerization in blocks): production scitillator pad near 8-10USD/pc and machining grooves near 20-25USD; in total near 30-35USD per scintillator without assemble. Version B (production of molded scintillators): price of mold for scintillator with groove near 30kUSD or near 17USD/pc and production scintillator near 3-4USD; in total near 20USD per scintillator without assemble. Version A have few advantages: light yield of scintillator is higher on 10-20% and scintillator more transparent. Also for version B groove in scintillator will be slightly tapered, if on depth the width of groove will be 1mm then width on surface will be 1.1 or 1.2mm. It's disadvantage of version B, as during inserting of fiber in the groove will need additional tool for keeping fiber inside scintillator. The two type of scintillators can be produced in IHEP and also we can order similar scintillators in outside firms. II. Support modules: First electromagnetic calorimeter in COMPASS has similar size 3x4 m**2 and total weight of calorimeter modules is 24t. The mechanical platform, chariot and light isolated cassette was designed and produced in Protvino workshop. ECAL1 calorimeter can move in three direction along vertical and horizontal and also along beam axes. I send you two photos with ECAL1 cassette and chariot. I have all working drawings and I can send you if it's need. III. Calorimeter module. I will consider design and cost estimate for Shower 18X0 Shashyk, as shown in your slide 7, page 2. Some assumption: 1) we will build a straight Shashlyk, due to large impact angles. It's correct? 2) the cost of preshower will not included; 3) the all materials and press mold will be produced and buys in Russia and/or IHEP. Of course WLS fibers, optical connectors and also diamond cutter and mill will be better to buy in USA or Europe. 1. The mold for scintillators. The price is around 30kUSD and production time 5-6 month, included design of mold and test after production. 2. The press mold for lead. The price is around 15kUSD and production time 5-6 month. 3. Will be need two molds for scintillators, due to production only 1 scintillator in mold per cycle for 10x10mm**2 size and life time of mold around 400k cycles. Total amount of modules is 1700 plus same spare module and around 200 scintillator in module, so total amount of scintillator will be more that 350k. 4. The same situation for press mold for lead. 5. The cost of lead sheets with 0.5mm thickness is around 6-7USD per kg in Russia. The size of lead sheet for stamping should have larger size on 10-15mm from each sides. So we should use 130x130mm**2 the lead sheet for stamping 100x100mm**2 the lead plate for modules. In this case we should buy around 17 or 20kg lead for each module. Really we can use only 60-70% of raw material. Total price of raw lead is around 100-140USD. The price of stamping is 0.3USD per cycle, for 100x100mm**2 will need around 200 cycles, or around 60USD per module. Total price of lead plates is 160-200USD. 6. The cost of 1.5mm scintillator is around 30-35USD per kg. The pure weight of scintillators in module is around 3kg, but we should take into account scintillator inside mold inlet. It's additional 20-25%. The total price of scintillators is around 110-130USD. 7. The cost of flange, steel rods, nuts and other, I can estimate based on COMPASS Shashlyk production, as 150-200USD. 8. The assemble cost I can estimate based on COMPASS production, as 150-200USD. So I don't add: preshower price, optical connectors, WLS fibers and mirrors on fibers, overheads cost in IHEP, transportation cost, assemble and production tools. Of course, it's only my estimate and can be reduce after production of prototypes. In summary about time line for prototype production of main version of your design. Will be need at least half of the year for production molds and 1-2 month for production prototype. We together with Sergey Chernichenko have few proposal about prototypes production, but detail description of our proposal I will send tomorrow after next discussion with Sergey. Again, I am sorry for long silence, but very difficult to collect information during sickness and also during beam run when you have the shift in experiment each 24 hours. Best regards, Vladimir. ________________________________________ From: Xiaochao Zheng [xiaochao@jlab.org] Sent: 15 December 2012 18:55 To: Vladimir Polyakov Cc: Zhiwen Zhao; Mehdi Meziane; Jin Huang; vladimir polyakov; polyakov@mx.ihep.ru; sergey.donskov@ihep.ru; donskov@ihep.ru; jpchen@jlab.org Subject: Electromagnetic Calorimeter Design for JLab SoLID Project Dear Vladimir: The work on the SoLID project at Jefferson Lab is progressing well and we have finalized our EC design: The Preshower will be a 2-X0 lead followed by 2cm of scintillators, read out by one WLS fiber embedded in the scintillator. The Shower will be the usual Shashlyk design as we discussed before. The lateral size will be 10x10cm and there will be about 1700, 60-cm long modules needed by SoLID. Another new aspect of the design is that we are considering to include about 100 smaller and shorter modules, with a 5x5cm lateral size. I have attached our latest writeup for the EC design. This is part of the document in preparation for our Director's Review. I hope this will faciliate our discussions. At the moment the most urgent question is how to support all modules, which are expected to weigh about 25 tons total. And this will be carried out by our collaborators from Argonne National Lab and other universities. We have not heard from you since our last email exchange on September 28th. In particular, can you comment on the new Preshower design and whether this can be done at IHEP? Do you have the adequate equipment for inserting or embedding the single WLS fiber inside the 2-cm thick scintillator? How will the Preshower be integrated with the Shashlyk shower in a single module? Also, what will be the cost estimate per module, for our new design? At the moment we would like to hear more committing words from IHEP such that we can move on to the design of the supporting system, and possibly prototype production. I have copied this email to all postdocs involved in the work, Dr. Sergey Donskov who had kindly expressed interest in our SoLID project, and Dr. Jianping Chen from Jefferson Lab, our SoLID project manager. We are looking forward to hearing from you! Best regards, Xiaochao Zheng ---------------------------------------------------------------------------- Associate Professor, Department of Physics, University of Virginia 382 McCormick Rd, Charlottesville, VA 22904 Telephone: (434) 243-4032 (during academic year); or (757) 810-2885 (summer) Homepage: http://people.virginia.edu/~xz5y/Main.html ----------------------------------------------------------------------------