1. Upgrade sensor meeting Coolbox for testing detectors/modules/staves
Liverpool University 18th April 2007
Richard French
Richard French

2. Coolbox concept: proposal parameters
Stave or Module or both?
Capability to reach SLHC operating temperature -25/30 oC).
Given starting point using a module box (hybrid dimensions are about 9cm2).
Dimensions and power issues are critical, If the design is for a stave, the cooling problem changes significantly.
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

3. Idealistic concept: Bespoke portable cold chamber
Box like structure from Aluminium clad thermally isolating foam – good for low noise and gnd.
Unit would house all readout devices or simple USB hub to link to control PC
Standard refrigerant gas system
Dry gas feed to internal manifold through pressure reg to alter DP
Peltier device to fine tune device temperature control either pc readout or built in, need to explore costing further with both options. USB device price unknown – awaiting info from supplier.
Kinematically mounted XY (Z?) translation stage for module (motorised-PC control?)
Anti-vibration mounts to isolate compressor or site compressor away from cold chamber under bench etc
USB-PC control for readout or built in control system but either possible (cost?)
No windows to the outside for Laser. Save condensation problems for window - Instead would prefer to use a 960nm (is spec correct?) Fibre coupled laser system, or customised with Pigtailed Laser Diode Module -1metre of single mode fibre - Diode driver –Board –P.S -Thermal kit all standard equipment for build such as this widely available from most optics manufacturers <£3k+vat - £400 to £2800 depending on supplier
Would mount the lens on a Z translation stage if required to adjust focal length/spot diameter etc
Can have USB readout/control for Laser input power – possibly link to PC control or build in to box
All PC control options use existing proven USB devices. Cost coming down and may be a significantly cheaper option as opposed to a built in device in terms of labour.
Interlock on access door for laser
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

4. Idealistic concept: Bespoke portable cold chamber.
Advantages:
Dimensions and operating temperature are not such a big factor
Refrigerant system is inexpensive and reliable
Subsequent repair or modifications can be done anywhere
Have been produced regularly at Sheffield -expertise is not an issue
Opportunity to make a working model or prototype and modify for final design should specifications change mid way (as usual).
To produce multiple boxes becomes significantly easier
Disadvantages
~Cost <£10k
Time taken to make prototype then final production box
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

5. Basic concept: Modified cold chamber using domestic freezer unit
Structure made from existing domestic freezer.
Modified compressor/condenser and refrigerant gas to meet our specification
Dry gas feed and pressure reg
Peltier device to fine tune device temperature control
Kinematically mounted XY translation stage for module
USB-PC control
No windows to the outside for Laser as before (this really is the way to go as you don’t need windows to lase through and has very good thermal shock properties).
?nm Pigtailed Laser Diode Module utilising 1metre of single mode fibre, Diode driver, board, power supply and Thermal kit – standard equipment from most optics manufacturers ~£400+vat
Would mount the lens on a Z translation stage if required to adjust focal length/spot diameter etc
Utilise existing laser driver for power readout
All PC control options use existing proven USB devices. Cost coming down and may be a significantly cheaper option as opposed to a built in device in terms of labour.
Interlock on access door for laser to existing laser driver
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

6. Basic concept: Modified cold chamber using domestic freezer unit
Advantages
Most of the hard work is done saving huge amounts of time.
Have made plenty of these
Low cost in development terms – maybe a suitable test bed for a full custom unit.
Reliability (to an extent depending on modifications)
Disadvantages
Dimensions will not meet specification
Not exactly pushing the boundaries of technology or getting even close
Long cooling/warming periods
Bulky and unattractive
Attaching readout devices becomes messy – need a feed-through and then all individual readouts linked separately.
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

7. Things to stick with to save BIG trouble
Using a patch cord based laser and ditching windows to lase through – safer too!
Full PC control or separate readout units not a combination of both
Peltier device is proven for these applications and ultra reliable
Use a standard configuration for refrigerant system, we do not need exotics for this purpose.
13/01/2019
© The University of Sheffield / Department of Marketing and Communications

8. Unknown information needed to start a comprehensive design
Laser specification, I have 960nm from somewhere but this is very close to IR, if we need to increase power then the whole system needs to be ditched. Typical sensor operations are in the 1540nm region.
Laser spot size crucial to mounting positions as determined by focal length > determines laser type as power need to increase x distance.
Dimensions of module or stave etc
Is the given temp range ok or do we want to go colder/warmer?
Humidity control? What DP is required?
Vibration spec
Noise from components – compressor etc
Size of readout equipment/connections to the detector all alters the height and positions of components and the overall size?
13/01/2019
© The University of Sheffield / Department of Marketing and Communications