Lab book

Background

To do

• Fit connectors to PCB
• Assemble second prototype
• Test mix of inks
• Test inks on non-tinned side

Log

4 march 2005

• CLEAPSS stands for Consortium of Local Eduction Authorities for the Provision of Science Services and is an advisory body. However it also dissemates info on statues etc. to schools
• Have spent

  PETTY CASH
    2.75 : 01 x Helium balloon
    2.39 : 01 x Butane cannister
    9.98 : 01 x Badger airbrush 
    4.40 : 02 x Indian inks
   13.16 : 01 x BNC socket, 01 x T2 box, 01 x Mains adapter, 01 x 3mm socket
   10.58 : 01 x Airbrush propellant, 01 x Ink
    2.65 : 01 x Ink
  ------
   45.91
  
  RS ONLINE
    8.88 : 01 x Araldite 2014
   42.48 : 02 x SHV Connectors, 02 x SHV Sockets, 02 x Alu Enclosures
    5.15 : 02 x PCB
   12.31 : 01 x Interlock switch
   14.22 : 01 x Copper tape
   18.13 : 02 x PETG plastic
  ------
  101.17
  
  MAPLIN ONLINE
    See Jerry Hart
  
  AR REGULATOR
    See Warren (about 130.00)
  
  TOTAL: > 147.08
  

3 March 2005

• Carved out a detecting panel on RPC and ordered SHV connectors and shiedling boxes from RS. Final RPC should now be completely shielded.
• Enquiry about HV and Freon came back:

  
  Mains-powered EHT supplies supplied for use in school science are limited to 5kV
  (to avoid generating X rays with teletron tubes, which could occur at higher
  voltages). They will also be limited a current output of less than 5mA (to
  reduce electric shock hazard).
  
  Van de Graaff generators can produce voltages of much more than 5kV, but the
  current available is very low and will not present an electric shock hazard,
  provided additional apparatus is not used to store charge.
  
  The most hazardous power supplies in school are HT supplies around 300V at 30mA
  or more and extra special care needs to be taken (shrouded plugs, teacher demo
  only) when using these to reduce electric shock hazard.
  
  The above information is based on good practice and advice from ASE and CLEAPSS
  over many years.
  
  I have passed your query on Greenhouse gases to a colleague who should reply
  separately soon.
  
  Regards,
  
  John Ellis, Physics Adviser
  CLEAPSS School Science Service
  Brunel University
  Uxbridge
  UB8 3PH
  Tel: 01895 251496
  Fax: 01895 814372
  E-mail: john.ellis@cleapss.org.uk
  Web-site: http://www.cleapss.org.uk 
    
  __________________________________________________________________________________________________________
  
  My colleague John Ellis passed on to me your enquiry about freons.
  
  There are a very large number of freons. The concern about them is NOT that 
  they are greenhouse gases, but that some of them are ozone-depleters and so 
  covered by the Montreal protocol and subsequent EU and UK legislation.
  
  Broadly speaking, except for certain specialist uses (for which a permit 
  would be needed) you have been unable to buy ozone-depleters, or equipment 
  containing ozone-depleters for some years. However, you have until 
  relatively recently been allowed to use up existing stocks of the chemicals 
  and to use equipment containing them. Now, you are no longer allowed to use 
  them for "diffusive purposes". (The legislation does not define this, but 
  we can guess that it means for uses which could permit the freon to diffuse 
  into the atmosphere.) Surplus stocks of the chemicals must be disposed of 
  via a licensed waste contractor. Equipment containing freons which are not 
  permitted (eg, old refrigerators) when it is no longer required must also 
  go via an approved route.
  
  What equipment do you have which contains freons? Which freons? We can look 
  it up in the legilstation, but there are many hundreds listed and a number 
  of different categories.
  --
  
  Dr Peter Borrows
  
  Director, CLEAPSS(r) School Science Service
  
  at Brunel University, Uxbridge, UB8 3PH
  
  Tel: 01895 251496 Fax / answerphone: 01895 814372
  
  Web site: www.cleapss.org.uk
  

• Got link about Freon 12 (http://www.airliquide.com/safety/msds/en/041_AL_EN.pdf) from Air Liquide site. Information courtesy of European Material Safety Data Sheets and were prepared by European Industrial Gas Association

2 March 2005

• Finished off model! See code/coincidence.py

1 March 2005

• Using Resistive Cathode Transparency, G. Battistoni et al. Nucl. Instr. Meth. 202 (1982) 459-464 (http://dx.doi.org/10.1016/0167-5087(82)90540-3)
• Tested sample one of Bombay ink on 75mm square (sample 2) gave reading of 0.73mA (40kΩ/sq.) and sample 1 on 45mm square gave reading of 1.12mA (26kΩ/sq.) Both are still much higher conductivity than desired but it is the best we have. The RPC with a single coating gives readings of 0.41mA (73kΩ/sq.) on upper surface and 0.50mA (60kΩ/sq.) on lower surface which places the opacity at about 0.6 to 0.7

26 February 2005

• Bought some Dr. P.H. Martin Bombay BLACK Ink. Tested it and found resistivity of first sample gives 1.5mA (20kΩ/Sq.) after one coat. We did another sample to verify this. Due to the patchy nature of a single coat it was slightly different. Took care to shake ink so that it didn't settle as before.

25 February 2005

• Recieved this info re: HV supplies:

  Brendan,
  Here is some text from the CLEAPSS handbook (copied from CLEAPPS CD).
  
  12.9.2 EHT units
  These give up to 5 or 6 kV. Those supplied for schools have their output
  currents limited to 5 mA or less and so are completely safe. Any EHT
  supply without this restriction on current should never be used.
  
  12.9.3 HT units
  Schools use HT units which have outputs greater than 40 V and are
  capable of supplying currents greater than 5 mA. They are necessary for
  electrophoresis (see section 13.7.10) and for some discharge tubes, ie
  some Teltron tubes which require a current larger than an EHT unit can
  supply; see section 12.6 (Electron beam and similar tubes). They can be
  used for Millikan's oildrop experiment.
  
  [Warning Symbol] HT units should be handled only by staff and supervised
  sixth form pupils and then with extreme care. Leads fitted with 4 mm
  plugs having sprung shrouds must be used (eg, P Harris P71810/0 etc) and
  care must be taken with other devices in the circuit.
  If units with HT outputs are to be used with younger pupils for their
  low-voltage outputs, their HT outputs must be disconnected first, eg, by
  removing the appropriate fuse. If the fuse is subsequently replaced, a
  large warning label must be fixed on the unit.
  

  Also was advised to try asking suppliers such as Griffin and Unilab how many units of HV and of what max voltage they have supplied in last 20 yrs or so.

23 February 2005

• Requested information from Isola, (http://www.isola-usa.com/) for the dielectric strength of the PCB bought, RS no longer provide the datasheet for the product.
• Cussans brought in the oscilloscope and detectors were mounted in a stack using variable height lifts and a board
• Wrote to CLEAPSS (http://www.cleapss.org.uk)
  

  Hi there,
  
  I was referred to you by the teachers on the Institute of 
  Physics mailing list 
  
  I have heard from two separate sources that secondary schools 
  are restricted to high voltage supplies of maximum of 5kV. I was 
  wondering if you knew if this is indeed the case and if so where 
  I can find the legislation?
  
  I am also interested in if there is any legislation on the use of 
  greenhouse gases (in particular, Freons) in a piece of lab apparatus.
  
  I have contacted the HSE but they don't have any specific legislation 
  for HV supplies or greenhouse gas usage, the DFES website refers you 
  to the HSE website and I'm now running out of leads!
  
  Regards,
  
  Brendan Arnold
  ----------------------
  BJ Arnold, Science 01
  ba1224@bristol.ac.uk

22 February 2005

• Created this page!
• Tested RPC resistivity quickly (with two stanley blades at different points on the surface). 6 coat side gave readings that fluctuated between very roughly 40mA and 20mA which gives resistivity of about 1kΩ/Sq. The 10 coat side has conductivity which vary between 25mA and 30mA which gives a resistivity of about 1kΩ/Sq.
• Planned to increase resistivity by sanding with wet & dry however coating is uneven and some areas are sanded to the glass before much difference is made to resistivity (i.e. just a couple of mV, not orders of magnitude). When actual sanding performed some mositure was applied unintentionally and a large patch of the ink was removed. In the end we removed all ink and decided to start again.
• RPC Placed in oven to dry briefly
• Order placed for Araldite 2014 - High Chemical and Temperature Resistance Epoxy Part. 332-1748. This was done since existing expoxy was chosen simply because it was slow dry time, we did not realise it had poor heat properties and is not suitable for HV application. Fortunately it won't be under HT since electrodes sit in centre of RPC however in future we shall use this new epoxy.
• Rejoined PTNC (http://networks.iop.org/) so could send this query:

  Hi there,
  
  I'm an undergrad. at Bristol Uni working towards 'An Affordable Particle
  Detector for Education'.
  
  The general outline is that we are to investigate building cosmic ray
  detectors that a school can afford on a tight budget.
  
  I would *really* appreciate it if anyone involved in the teaching of science
  out there would answer a short questionnaire of about 6 questions that I've
  toiled on for the past few hours. It can be found at...
  
  http://brendan.sdf-eu.org/misc/detector_survey.php
  
  All data collected is for our own research purposes and won't be passed onto
  other groups.
  
  Also if anyone else knows of any other ways I can contact science teachers
  in the UK (particularily physics) please let me know! I have already posted
  a similar message to the Times Educational Supplement forums.
  
  Any problems, please email me at ba1224@bristol.ac.uk
  
  Thanks!
  
  Brendan Arnold
  4th Year Undergrad. Bristol University
  

• Detectors for Particle radiation 2nd Ed., Cam. Uni. Press Konrad Kleinknect Pg 99:
  Gives good description of streamer formation
• S. Eidelman et al., Phys. Lett. B 592, 1 (2004) Physical Review (http://pdg.lbl.gov/2004/reviews/contents_sports.html)
  Gives lots of CR info and figures that can use in write-up