1. October 28-th, 2005Straw tracker 1 Status of Straw Tracker for P236 P.L. Frabetti, V.Kekelidze, K.Kleinknecht, V.Peshekhonov, B.Peyaud, Yu.Potrebenikov, R.Wanke and others. Dubna-Mainz-Saclay collaboration V.Kekelidze

2. October 28-th, 2005Straw tracker 2 Layout of the Tracker P(   ) = 60 GeV/c P(K + ) = 75 GeV/c Holes in Straw-Chambers 5 cm radius Asymmetric holes at St 4 & 5 Magnets: p t kick 270 and 360 MeV/c Ke4: Region II - Acceptance < 4 × 10 -7 Extrapolation from Region II+III - Acceptance < 2 × 10 -8 (see G.Ruggiero’s 10.06.05 talk)

3. October 28-th, 2005Straw tracker 3 Advantages: can (in principle) operate in vacuum decay volume can be designed without internal frames and flanges can operate at high rate of hits good space resolution (~130  m/hit for  9.6 straw) small radiation thickness (~0.1% X 0 per view) Choice of Straw Chambers

4. October 28-th, 2005Straw tracker 4 Glue – 5  m 12.5  m 0.2  m Al 9.6 mm25  m Gold plated Tungsten wire 30  m Straw Tracker Design 8.8 m186.3 m from T0 5.4 m 7.2 m k12hika+ (Niels)  About 2000 * 6 -> 12000 straws in total 3 coordinates 4 coordinates 2 coordinates 1 coordinate 10 cm 2300 mm To fit easily into decay volume an octagonal shape is proposed Inefficiency region Two double layers form a view Gas mixture: 20%Ar+80%CO 2 12 ns rise time 100 ns total width Polycarbonate spacer, 25 mg

5. October 28-th, 2005Straw tracker 5 Tooling for Single Straw pressure tests straw gas This tooling will be used in vertical position

6. October 28-th, 2005Straw tracker 6 Tooling for Single Layer Vacuum Tests This tooling will be used in vertical and horizontal position Up to 10 straws 2300 2364 For vacuum pumpsFor gas system Free for movingFixed part For measuring devices

7. October 28-th, 2005Straw tracker 7 Tooling for Single Layer Vacuum Tests

8. October 28-th, 2005Straw tracker 8 Tooling for Single Layer Vacuum Tests

9. October 28-th, 2005Straw tracker 9 Tooling for Single Layer Vacuum Tests

10. October 28-th, 2005Straw tracker 10 Preliminary tests schedule first batch of straws deliveryNov.-Dec. 2005 pressure testby the end 2005 vacuum testDec.05 - Jan.06

11. October 28-th, 2005Straw tracker 11 Replay on referee’s questions  Is the straw tube tracker the only viable option for the experiment? The following requirements makes this choice almost unique: - minimum radiation thickness; - large area covered; - operation in vacuum; - beam hole in the centre without dead material.  Is the tracking performance adequate for the required resolution? The resolution requirement is 130 mkm. To achieve corresponding performance a stability of readout electronic, HV, T, Gas mixture etc. should be provided. The SC system will be used on-line, mapping of the anode wire positions will be implemented offline. A time dependent correction of track position along a wire is foreseen as well. Senility of the readout should be about 3fC.

12. October 28-th, 2005Straw tracker 12 Replay on referee’s questions  What is the gas to be used and what is the maximum drift time? for the 9.56 mm straw: gas mixture Ar/CO 2 (70/30) provides max drift time of130 nsec, and gas mixture Ar/CO 2 /CF 4 (63/27/10) provides max drift time of120 nsec

13. October 28-th, 2005Straw tracker 13 Replay on referee’s questions  Will the tracker be able to perform inside such vacuum in terms of mechanical stability? Comment: The AMS experiment has experience on running 1.5 m long straws in vacuum. We advise to contact them. Instability will be at the moment of vacuum switching off / on. Stability of mechanical and gas leak properties of the detector (straws) in time is part of R&D program. Various possible mechanical designs will be studied first on the prototype. Concerning AMS straws, those are used as TRD detector and have different requirement. In particular, a film of 72 mkm thickness is used for straw production which is rather thick for our case.

14. October 28-th, 2005Straw tracker 14 Replay on referee’s questions AMC straws

15. October 28-th, 2005Straw tracker 15 Replay on referee’s questions  What will be the readout electronics? Front-end electronic should have small level of noise, senility – 3fC, and will be placed including proper cooling onto the chamber frame. As the requirements for the straw chamber read-out are not particularly different from other drift chamber read-outs as e.g. in NA48/2, we will revert to well-known technology. The digitization will be performed either by GPX TDC's, which are an improved version of the TDC's used by the current NA48/2 drift chamber read-out, or by CERN-developed HP-TDC's, which are currently used in the NA48/2 beam spectrometer read-out. Both TDC's fulfill all our basic requirements. For the data transfer we are planning to use the TELL1-board, which has been developed by the LHC-B experiment, and is also foreseen to be used by other P326 detector components. Also this board fulfills all our requirements, in particular on the rate, and allows maximum flexibility. At the moment, a prototype straw chamber read-out board based on GPX TDC's is being built, and will be tested in the next months.

16. October 28-th, 2005Straw tracker 16 Replay on referee’s questions  What will the interface look like to the outside world? This will became clear after certain stage of R&D program.

17. October 28-th, 2005Straw tracker 17 Replay on referee’s questions  What is the priority for the experiment, what is the timetable for the R&D? A detailed R&D program is under preparation. However some milestones are already foreseen: - for the first year: straw production technology, mechanical stability test at NTP & in the range of (~0.8-1) NTP small prototype construction, mechanical and gas leak tests; prototype test in the beam; - for the second year: full scale prototype construction and tests in the beam with corresponding electronics.

18. October 28-th, 2005Straw tracker 18 Future planning Future detailed planning will became possible after:  first mechanical and leak tests with real straw samples  more definite information on available resources JINR PAC in particle physics on 10-11 Nov.